NOTE - I got this final report from the "Missing Learjet" web site before that site was taken down after the plane was found.  I saved the text locally, but apparently did not get the embedded pictures.  This page is a link from my main Learjet Crash page, so go there for the full overview.

  

Missing Learjet N388LS

And Crew

 

Investigation – Final Report

 

 

September 19, 1998

 

 

 

 

 

 

 

Prepared By:             Scott Estey

 

Table of Contents

 TOC \o "1-1" Missing Learjet N388LS....................................................................................................................................... PAGEREF _Toc430749931 \h 1

Table of Contents................................................................................................................................................ PAGEREF _Toc430749932 \h 2

1.      Abstract............................................................................................................................................................ PAGEREF _Toc430749933 \h 3

2.     Purpose................................................................................................................................................................. PAGEREF _Toc430749934 \h 4

3.      Accident Investigation Process........................................................................................................ PAGEREF _Toc430749935 \h 5

4.      Collection of facts and evidence................................................................................................... PAGEREF _Toc430749936 \h 6

4.1.       Analysis of FAA Radar NTAP Data................................................................................................. PAGEREF _Toc430749937 \h 7

4.2.       Analysis of FAA Voice Transcripts............................................................................................. PAGEREF _Toc430749938 \h 9

4.3.       Examination of FAA Notams and Equipment Logs............................................................ PAGEREF _Toc430749939 \h 13

4.4.       Analysis of Weather Data............................................................................................................... PAGEREF _Toc430749940 \h 14

4.5.       Pilot Qualifications and Flight Experience....................................................................... PAGEREF _Toc430749941 \h 18

4.6.       Aircraft Equipment List and Maintenance Logs.............................................................. PAGEREF _Toc430749942 \h 20

4.7.       Interviews................................................................................................................................................... PAGEREF _Toc430749943 \h 21

4.8.       Reconstruction of flight approach profiles................................................................. PAGEREF _Toc430749944 \h 23

5.      Eyewitness Reports and Testimony............................................................................................... PAGEREF _Toc430749945 \h 26

5.1.       Warren NH reports.............................................................................................................................. PAGEREF _Toc430749946 \h 27

5.2.       Fuel Odor Reports................................................................................................................................ PAGEREF _Toc430749947 \h 29

6.      Findings of Contributing Factors................................................................................................. PAGEREF _Toc430749948 \h 31

7.      Determination of Probable Cause................................................................................................. PAGEREF _Toc430749949 \h 40

Aircraft Equipment List................................................................................................................................. PAGEREF _Toc430749950 \h 44

NTAP Radar Viewpoint...................................................................................................................................... PAGEREF _Toc430749951 \h 45

ILS 18 Approach at Lebanon......................................................................................................................... PAGEREF _Toc430749952 \h 46

VOR 25 Approach at Lebanon...................................................................................................................... PAGEREF _Toc430749953 \h 47

8.      Glossary.......................................................................................................................................................... PAGEREF _Toc430749954 \h 48

 

 


 

 

1.        Abstract

 

On December 24, 1996, a Learjet 35A, registration number 388LS conducted a reposition flight from Bridgeport, CT to Lebanon, NH. During this flight the aircraft performed two instrument approaches while attempting to land at Lebanon Airport. At some point during the second non-precision VOR approach, the aircraft disappeared from tracking radar and was never heard from again. The aircraft is presumed to have crashed and the crew fatally injured although no evidence of a crash site has been found to date.


 

2. Purpose

 

The purpose of this report is two-fold. First, it is a empirical study of all known facts concerning the disappearance of the Learjet. Second, this report attempts to:

1.     Identify contributing factors of the accident.

2.     Determine the probable cause of the accident.

 

Because we do not definitively know the answers to these questions, we can presume, to some degree that the conclusions presented here, although based in fact, contain interpretations of facts and events which are concluded to be contributing factors or causal events. Probable cause then can be determined by placing each of these events into a causation chain to show their relevance and effect to the known result.

 

“Probable cause is defined as an event or events supported by evidence strong enough to establish presumption, most likely to have occasioned or effected an accident. Act(s) or omission(s) which resulted in the accident and for which there is at least more evidence than against. Probable cause applies to anything which appears reasonable on the basis of evidence or logic, producing an effect or resulting in an accident, but is neither certain nor proved.” [1]

 

To this end, the conclusions presented herein represent the culmination of 1 year’s analysis of collected facts and knowledge concerning this accident.  Through a deductive scientific process, it assumes that a definitive factual conclusion is not possible at this point in time but attempts to provide a causation chain of events which support a probable cause of the accident.
 

3.        Accident Investigation Process

 

As is adopted by international standard, a 4 step process for accident investigation was followed:

 

1.              Collection of factual information

2.              Analysis

3.              Conclusions

4.              Findings, determination of Probable Cause [2]

 

As with any accident investigation, it is the object to ascertain the probable cause of the accident by identifying contributing factors and causal events which have logical connection to one another and when examined as a chain lead to a reasonable and likely conclusion.

 


 

4.        Collection of facts and evidence

 

The majority of facts regarding this accident were initially collected by several state and federal agencies. The collection of empirical and factual data is the basis for subsequent deductive scientific study and analysis with an outcome of attaining a highly probable, factually based conclusion.  The facts and evidence concerning this accident can be grouped as follows:

·     FAA Radar tracking NTAP data

·     FAA Voice communication transcripts

·     FAA NOTAMS, Equipment maintenance logs and Airport Tower Controller logs

·     Weather data

·     Pilot Qualifications and Flight Experience

·     Aircraft equipment list and maintenance records

·     Interviews of pilots, aviation safety experts, Air Traffic Controllers, owner’s of the missing aircraft, co-workers of the pilots and company officials who have intimate knowledge of the flight, the aircraft or it’s crew.

·     Eyewitness reports collected by New Hampshire Fish & Game Department and New Hampshire State Police.

·     Analysis of reconstruction of the attempted VOR approach during the flight.

 

 

 


 

 

4.1.         Analysis of FAA Radar NTAP Data

 

Radar tracking NTAP raw data was obtained from the FAA ARTCC center in Nashua, NH. This data represents,

·        NTAP plot depicting the transponder code assigned to N388LS (code 1773) commencing with the initial radar contact through 1030 hours EST, December 24, 1996.

·        NTAP plot depicting all transponder target returns for a 35 nautical mile (NM) radius centered on Latitude 43 deg,38’00” N, Longitude 72deg,18’00” W commencing at 0930 hours EST through 1030 hours EST, December 24, 1996.

·        All primary radar and weather returns for a 35 NM radius centered on Latitude 43 deg,38’00” N, Longitude 72deg,18’00” W commencing at 0930 hours EST through 1030 hours EST, December 24, 1996. [3]

 

The above data was collected by radar antennae sites located at West Cummington, Massachusetts [QHA] (Latitude 42deg,28”30’ N, Longitude 72deg,58”02’ W) and Turo, Massachusetts. Radar returns from these sites we’re certified by the FAA using the tolerances of plus or minus 1/8 nautical mile (760 feet) in range from the radar site and plus or minus 2 Azimuth Change Pulses (ACP’s) or 0.1758 degrees of azimuth from the radar site. Echo reflection time is 12.36 micro seconds for each radar mile from the site.  This amounts to radar reflections in the area of concern occurring every 11 seconds. [4]

 

 

Approximately 10,000 records of data were analyzed to answer the following questions:

·        During the recorded period of time, was an emergency transponder code of 7700, 7500, or 7600 received?

·        During the recorded period of time, was the discrete beacon code of N388LS, 1773, ever received subsequent to the last correlated known position of the aircraft at 15:01.47 UTC (10:01.47 local) Latitude 44deg,49”, Longitude 08deg,23”, Altitude 4800 MSL?

·        During the recorded period of time, what were the bases of the radar coverage in the immediate area of the flight of N388LS?

·        Were the position reports given by the flight crew of N388LS accurate in describing their true position?

 

CONCLUSIONS:

 

·        An emergency transponder code was never received during the recorded period of time.

·        The discrete beacon code 1773 of N388LS was never again received after it’s last correlated known position at 15:01.47 UTC.

·        Generally, within the recorded area, radar coverage bases during the recorded period were observed to be as low as 4200 ft MSL and as high as 4800 ft MSL.

·        When comparing the radar data and voice communication transcripts of conversations between the flight crew and Lebanon Tower controllers and Boston Center Controllers, the position reports given by the flight crew indicated discrepancies between the actual position of the aircraft and it’s perceived position by the flight crew relative to the airport and navigation aids. These discrepancies were noted as being as much as 4 nautical miles in difference.

·        The radar data analysis was not used to corroborate eyewitness testimony or to establish conclusions about eyewitness reports. In all cases, witnesses testified that the aircraft they observed was well below 4000’ MSL and in most cases was at tree-top level or very close to the ground.  If the witnesses are to believed and presuming what they observed was the Learjet, the radar would never have recorded a target below 4200’ MSL.

 


 

4.2.         Analysis of FAA Voice Transcripts

 

Transcripts of all voice communications between the flight crew of N388LS and FAA Controllers for the entire flight commencing at 1419 UTC (9:19 EST) hours on December, 24, 1996 and ending with the crew’s last transmission at 1459:23 UTC (9:59.23 EST) were obtained from the FAA. In addition to the transcripts, voice recordings of the communications were obtained.

 

CONCLUSIONS:

 

·        Analysis of the voice recordings indicated that HAYES, the PIC (Pilot in Command), was handling all radio communications on board the aircraft.

·        In examining the intonation and context of voice recordings of HAYES, it is clear that there was no abnormal stress, problematic situation or serious in flight emergency which was detectable in his communications with air traffic controllers.

·        A chronology of voice communications which represent significant facts and contributing factors of this accident follows.

·        The flight filed and was cleared directly to the Lebanon VOR. [R47=boston center controller]

 

1427:01 R47        Lear eight lima sierra proceed direct to

              Lebanon when able.

1427:04 N388LS Cleared direct to Lebanon ah three eight

              lima sierra.  [5]

·        The flight was shortly later cleared to proceed direct to BURGR intersection which represents the IAF (initial approach fix) for the ILS 18 approach to Lebanon. [R37=boston center controller]

 

1446:14 R37    Lear eight lima sierra leaving ah once you

              leave five thousand proceed direct BURGR

              for the ILS approach

1446:19 N388LS okay out of five thousand direct BURGR lima

              sierra. [6]

 

 

·        The flight was then cleared to initiate the ILS 18 approach from their present position. [R37=Boston center controller]

 

1447:21 R37    and eight lima sierra maintain four thousand

              seven hundred until established on a portion

              of the approach cleared ILS approach Lebanon

1447:27 N388LS okay four thousand seven hundred until

              established cleared the approach ILS one

              eight thanks. [7]

 

·        The flight was instructed to report BURGR (IAF) intersection inbound. The flight crew was not able to obtain appropriate course guidance from the localizer. [LC=Lebanon Tower Controller]


1448:55 LC     november eight lima sierra report burger

              inbound

1450:54 N388LS ah and tower Lear three eight eight lima

              sierra we’re burger inbound we’re not

              getting the localizer

1451:02 LC     Learjet eight lima sierra roger are you

              continuing with the approach or ah execute

              the missed approach present position your

              choice localizer’s in the green. [8]

 

·        After 45 seconds of silence and not receiving appropriate localizer signals for the approach, the flight crew asked to initiate a missed approach procedure. [LC= Lebanon Tower Controller]

 

1451:43 LC     Learjet three eight eight lima sierra say

              intentions

1451:47 N388LS three eight eight lima sierra we’re going

              to execute the missed here ah ah we’re not

              receiving the localizer

1452:03 LC     Learjet eight lima sierra published missed

              approach contact Boston center one three

              four point seven. [9]

 

 

 

·        The flight re-contacted Boston center controllers and announced they were executing the missed approach procedure for ILS 18 approach. The flight crew was apparently confused or unsure of the appropriate localizer frequency for the ILS 18 approach and attempted to confirm this with the controllers. [R37=Boston center controller]

 

1452:51 N388LS and for Lear three eight eight lima sierra

              is with you on the missed

1452:54 R37    ah Lear three eight eight lima sierra roger

              and say your intention

1452:57 N388LS ah roger ah just confirm that frequency is

              one eleven point nine

1453:02 R37    no the tower is that what you’re looking for

              the tower frequency

1453:06 N388LS No to the localizer (frequency)

1453:10 R37    okay stand by

1453:17 R37    november three eight eight lima sierra fly

              the ah published missed approach ah

              procedure maintain five thousand for now

              I’ll get right back to you

1453:24 N388LS Roger five thousand on the published missed

1453:29 R37    okay the localizer

1453:35 R37    eight eight lima sierra the localizer is ah

              one one one point niner is the frequency for

              the localizer

1453:41 N388LS okay we’re unable to get it ah uhm stand by

              one. [10]

 

·        The flight crew then asked to perform the VOR 25 approach circle to runway 18. Center controllers approved this maneuver and directed the flight to the VOR. The flight was then handed off to Lebanon tower controllers for the remainder of the approach. [LC= Lebanon Tower Controller]

 

1457:20 N388LS Lebanon tower Lear three eight eight lima

              sierra is with you on the VOR two five

              circle to land one eight

1457:32 LC     Learjet three eight eight lima sierra

              Lebanon tower good morning again ah say your

              position now

1457:36 N388LS roger we’re five miles to the ah southeast

              of the VOR

1457:43 LC     roger eight lima sierra report the VOR

              outbound altimeter’s two niner eight three

              I’ll give you a wind check ah in the

              Vicinity of the VOR inbound winds are

              Currently two three zero at five land

              Straight in to two five if you like

1457:57 N388LS that’s what we’ll do we’ll take two five

1457:59 LC     Roger. [11]

 

·        The flight crew, as instructed, reported passing VOR outbound. This was the last communication received from the flight crew. [LC= Lebanon Tower Controller]

 

1459:26 N388LS Lear three eight eight lima sierra is

              VOR outbound. [12]

 

·        After 8 minutes and 7 seconds, the Lebanon tower controllers attempted to raise the flight on frequency without success. [LC= Lebanon Tower Controller]

 

1510:06 LC     Learjet eight lima sierra say your position.

1510:29 LC     Learjet three eight eight lima sierra

              Lebanon tower say your position. [13]

 


 

 

4.3.         Examination of FAA Notams and Equipment Logs 

 

An inspection and examination of FAA NOTAMS (Notices to Airman) and equipment logs from ARTCC Boston, Lebanon Tower and Burlington FSS revealed the following facts:

 

·        The St. Albans radar antennae site, typically used for aircraft tracking in the Lebanon area was out of service during the Learjet’s flight.[14]

·        Local NOTAMS for LEB (Lebanon airport) indicated that none of the normal instrument landing equipment was inoperative at the time of the flight but that, as a result of the aircraft disappearing and it’s presumed crash, the ILS localizer was removed from service at 1835 UTC on 12/24/96. It was flight checked and deemed reliable and returned to service at 1730 UTC on 12/26/96.  The LEB VOR was similarly removed from service at 1955 UTC on 12/24/96, checked and returned to service at 2210 UTC on the same date. [15]

 

CONCLUSIONS:

 

·        Malfunction of ground based radio navigation equipment was not reported or detected by FAA personnel on December 24, 1996.


 

4.4.         Analysis of Weather Data

 

Analysis of all available weather data including surface analysis charts, METAR data, and winds aloft reports was performed by Evan Gillespie of State University of NY at Albany.  Evan’s conclusions are the result of eight months investigation and examination of weather data collected for December 24, 1996.

 

Summary #1:

Although temperatures near the ground were just slightly above freezing at the time of the accident, there was a strong inversion (temperature increases as elevation increases). The freezing level was estimated to be at 8000 feet that morning over Lebanon (weather balloon data). At 0900 local time, a propeller plane flying several thousand feet above Lebanon VOR reported a temperature of +8 degrees. There is a very slight chance that icing could have existed in the low cloud layer (which extended from 1,800 to 4,000 ft MSL). This layer was a stratus cloud. Even if icing did exist in this cloud, the rate of accumulation of ice would have only been a trace, or light at most. Also, because this layer was thin and the temperature was above 0 degrees C below and above this layer, it is extremely unlikely that airframe ice would have stayed on the wing long enough to cause a significant loss of lift.  Other aircraft that departed or arrived at Lebanon Municipal did not report any icing during the time the Learjet disappeared. [16]

 

 

Evan’s report also summarized the winds aloft.

 

SUMMARY #3

Wind at Lebanon Airport during the time of the disappearance was from the south at 5 knots.  Pilot reports and weather balloons (along with the Learjet’s speed estimations from Boston Center radar fix data) indicate that the wind at the procedure turn level was from the southwest at 70 to 80 knots.” [17]

 

Evan’s analysis also suggested that a thick layer of cloud existed at the lower level of the approach area. Evan further suggests the existence of elevated stable layers created potential wind shear and turbulence within the approach area.

 

These layers are generally called elevated stable layers. Many are horizontal, not strongly sheared, and smooth. However, there are situations when ascent or descent through elevated stable layers will expose you to unexpected wind shear and turbulence. The effects…occasionally contribute to serious flight problems. …When cold airmasses move out of a mountainous area [as was the case on December 24],cold air will often remain trapped in the valleys as warmer air moves in aloft. A strong elevated inversion typically will be found just below the mountain peaks. If strong winds are present at and above the mountain peaks, large vertical wind shears will exist in the inversion between the weak, cold airflow in the valleys [Lebanon Airport] and warmer air flowing across the mountains… [18]

 

We know that a stratus cloud existed from 1,800 ft to 4,000 ft MSL at the time of the disappearance. Stratus clouds can only exist in relatively calm and moist air. This means that the air must have been relatively calm (less than 15 knots) through 4,000ft MSL. Using the theory of an elevated stable layer (a warm layer that flows over a cold layer) we can assume that the shear layer existed just above 4,000ft MSL, and also the shear layer was probably extremely thin (the wind increased from 10 knots or so to 70-80 knots in a matter of feet). This is significant because published procedure turn height for the VOR RWY 24 approach is 4,300ft MSL.” [19]

 

Current weather observations collected on an hourly basis reported the following weather at Lebanon airport on 12/24/96:

 

Time  Wind      Visibility   Ceiling   Temp/DP   Alt.

0945L 190@ 5kts  5 sm w/ fog 1200’     05/03     2983

1050L 200@ 5kts  6 sm w/ fog 1200’     06/04     2979

1145L 210@ 7kts  6 sm w/ fog 1700’     07/06     2977 [20]

 

 

 

 

Independent interviews with pilots who landed at Lebanon Airport on December 24, 1996 subsequent to the Learjet disappearance corroborate the weather analysis by Evan.

 

During a phone interview with Bill Oakes, PIC of a Cessna Citation Jet N800HS, Mr. Oakes related the following:

 

[He] was flying to LEB from TEB [Teteroboro NJ] and at 10:45 L [he was] told to hold at BURGR [intersection]. Did one turn then cleared for ILS 18 APP. Initiated approach and got full deflection on glideslope (vertical reference to approach path) then full deflection on localizer (horizontal reference to approach path). GPS was on board. Lower scud layer observed over airport. Performed missed approach procedure. Prior to approach, tower announced they were working on ILS equipment. Not announced on NOTAMS or ATIS (automated terminal information system). Shot VOR 25 approach with no incident. Was very windy, no precipitation, no icing to his recollection. Strong southwest wind. [21]

 

Peter Knox, another pilot landing at Lebanon within the same period of time related the following in a written transcript of his flight.

 

This represents my best memory of the events of December 24, 1996.  I was about 45 minutes behind the Learjet in making the approach at Lebanon. At 7000’ there was a southwest 60-70 knot wind.  I was cleared to transition from the VOR to BURGR [intersection], cleared for the ILS 18 [approach] to report completing the procedure turn and established inbound in the localizer.  After the turn I thought I was on the localizer and started to descend to 2800’ (BURGR glideslope intercept). At an altitude around 4000’ I realized my localizer and glideslope bars were not moving so I leveled out to find out what was wrong. Tower called to ask what I was doing as I, by that time was almost over the field. I said my instruments were evidently out. Tower advised that the ILS was working and asked my intentions. I advised a missed approach and said I would like to go back to the VOR and try again. Tower said VOR 25 approach was available and to climb to 7000’ and turn left direct to VOR and report to Boston Center. As I was headed to the VOR a citation [jet] announced the ILS was not working and he was declaring a missed approach. He was told that ILS operation was normal. I held at the VOR while he made his VOR 25 approach. I was then cleared and made my approach.  I was not in ground sight at the VOR inbound (2300’) but estimate broke out at about (1800’) 2-3 miles from [the] airport. Don’t remember any icing. [22]

 

 

 

 

CONCLUSIONS:

·        Icing did not play a role in this crash. [23]

·        A strong horizontal wind shear layer existed within several hundred feet of the procedure turn level of 4,300 feet MSL. This wind shear layer along with orographic turbulence caused by the wind flow over mountains, could have been a factor in this accident. [24]

·        A severe change of wind speed and direction between the surface and the initial approach altitude (4300’MSL) existed and the point at which this change exactly occurred in the atmosphere was unknown to the flight crew.

·        Marginal VFR (visibilities above 3 sm) conditions existed when below the cloud bases (below 1800’ MSL) or above the cloud tops (above 4300’ MSL). [25]


 

4.5.         Pilot Qualifications and Flight Experience

 

Transcripts of the flight crew’s certification and recency experience requirements were obtained from the FAA and NTSB. [26]

 

·        Pilot in Command

Patrick Hayes DOB 8/12/66

Certificates Held: ATP(#046701502), MEI, CFII

Medical Certificate: First Class, expiring 5/31/97, no waivers.

 

Flight time experience as of 12/21/96

Day          3617

Night        632

Instrument   186

PIC          3058

Single Engine 2430

Multi Engine 1820

Turbine      832

Jet          832

Lear 35A     750

 

Last 30 days 40

Last 90 days 110

 

Total        4250

 

Patrick had been employed with Aircraft Charter Group for a period of approximately two years prior to the accident.  Patrick had flown several multi-engine aircraft during his employ as a pilot including some jet aircraft. During the summer months of 1996, Patrick obtained a type rating at Flight Safety for the Learjet 35A which would allow him to act as PIC in that aircraft. [27]  He was due for recurrency training in the Learjet in January, 1998. [28] Patrick had no history of accidents, incidents or violations on his pilot certificate record according to the FAA. [29]
 

·        Second in Command

Johan Schwartz DOB 03/03/66

Certificates Held: ATP (#043581872), MEL, CFI

Medical Certificate: First Class, expiring 1/31/97, no waivers.

 

Flight time experience as of 12/20/96

Day          1911

Night        135

Instrument   120

PIC          1582

SIC          484

Single Engine 1070

Multi Engine 996

Turbine      597

Jet          267

 

Total        2066

 

 

Johan had been employed with Aircraft Charter Group on a part-time basis for 1 year and within the last year prior to the accident had begun flying full-time with the company. Johan obtained significant experience while working at small commuter airlines such as Precision Airlines of Manchester, NH in the capacity as a first officer. Johan’s flight experience was commensurate with that of second in command responsibilities of the Learjet 35A aircraft.  Johan did not possess a type rating for the Learjet 35A but had historically performed all the functions of SIC (second in command) in the aircraft. Johan had no history of accidents, incidents or violations on his pilot certificate record according to the FAA. [30]


 

4.6.         Aircraft Equipment List and Maintenance Logs

 

Lear N388LS was by all means a fully IFR equipped aircraft capable of global travel. The aircraft was equipped with a redundant power supply, dual Collin Nav/Com radios, Dual DME, Dual Transponders, Dual Flight Director, ADF, radio altimeter, standby attitude gyro, weather radar and air/ground telephone. A VLF/Omega navigation receiver had been installed in the aircraft within a month of the accident.  In addition, a Trimble 2102 panel mounted GPS had been installed.  The aircraft also had a very sophisticated auto pilot capable of flying the aircraft in several flight profiles.

 

Aircraft maintenance logs for N388LS, Serial #388, at the time of this investigation were unavailable as they are now owned by the insurance company of USAIG.  Phone interviews with the Director of Maintenance for Aircraft Charter Group, owner, chief pilot and Aircraft Charter Group Management characterized the aircraft as “an excellently maintained aircraft. 388LS was not a problem aircraft.” [31]

Further, the aircraft was maintained under Part 135 scheduled maintenance regulations requiring periodic checks of all systems.  The aircraft had completed an international flight the week before it’s disappearance with no incident. The Director of Maintenance of Aircraft Charter Group stated that this aircraft was in compliance with Part 135 periodic scheduled maintenance regulations at the time of the accident and that no maintenance had been deferred prior to the accident. [32]

 

 


 

4.7.          Interviews

4.7.1                Lars Linden

During the period of 9/97 to 9/98 I conducted several phone interviews with Linden to collect knowledge he possessed regarding the flight crew and the aircraft.

As a career pilot with over 10,000 hours of Learjet time, Linden provided significant personal experience knowledge of the aircraft. In addition, Linden was part-owner of N388LS and leased the aircraft to Aircraft Charter Group for use in it’s fleet of charter aircraft. Linden flew with several of the pilots using his aircraft. In particular, Linden was a mentor to HAYES and was involved in HAYES’s training on the Learjet. In a sense, HAYES was his protégé and in a relatively short period of time, HAYES was made captain in the aircraft. HAYES completed type-rating training at Flight Safety and performed the duties of PIC in the Learjet in Lars’ absence.  HAYES obtained his type rating in the Learjet with 1 year of the accident. As Linden was part-owner of the aircraft, he assured that the aircraft was maintained to the highest standard and “flown by the book.” Linden’s professional opinion of HAYES was that “Pat was a conscientious pilot with good skills.” He also stated that “…of any weakness identified in Pat he lacked good situational awareness.” Linden further described HAYES as being a very generous person and very close friends with Schwartz. Linden indicated that HAYES was very familiar with the GPS on board the aircraft and that he used it readily on most every flight.  Linden indicated that the GPS was an after-market installed, panel-mounted Trimble 2102 GPS navigation instrument and that it was in no way linked, connected or attached to the auto-pilot or other navigation systems in the aircraft and that it was intended to be used as a backup to the primary navigation instruments. Linden stated that it was company policy and practice to use NOAA-geodetic approach plates for all instrument approaches conducted.  Lastly, it was Linden’s opinion that as is consistent with the voice recordings of the communications of the flight crew, specifically that HAYES’s voice is recorded during all of the communications with ATC, that HAYES and SCHWARTZ switched roles as well as seat positions in the aircraft during the reposition flight from Bridgeport to Lebanon on December 24, 1996. Linden stated that in most commercial flight operations, the duties of the SIC (Second in command) include radio communications and navigation and that the duties of the PIC (Pilot in command) are to fly the aircraft.  In light of this and the fact that HAYES was handling all voice communications, Linden believes that because HAYES and SCHWARTZ were such close friends, HAYES’s generous personality and friendly nature and that the flight to Lebanon was being conducted under 14 CFR Part 91 non-commercial status (the aircraft was not conducting a commercial operation during the leg from Bridgeport to Lebanon as it was not carrying paying passengers) and that it was common practice to allow SIC pilots “left seat time”, that HAYES allowed SCHWARTZ to perform the duties of PIC sitting in the left seat while HAYES was performing SIC duties in the right seat.  Linden feels that it is significant that SCHWARTZ was flying in the left seat during that flight. Linden indicated he would not have “given” SCHWARTZ the left seat that morning and in hindsight, would not have allowed HAYES and SCHWARTZ to fly together that day.  In fact, this flight was the first time that HAYES and SCHWARTZ had ever flown together in the Learjet. [33]

 

4.7.2    Carol Helms

During the period of 9/97 and 9/98 I conducted several phone interviews with HELMS. HELMS was part owner and a member of management of Aircraft Charter Group, the charter company which employed SCHWARTZ and HAYES. HELMS corroborated much of LINDEN’s statements regarding HAYES and SCHWARTZ. Although HELMS was not involved in the day to day operations of the flight department she did know the pilots of the aircraft. HELMS indicated that, in her opinion, SCHWARTZ was a relatively in-experienced Learjet pilot and that in fact, he had never obtained or attended Learjet 35A specific training conducted at Flight Safety International. She confirmed that SCHWARTZ was not type-rated in the aircraft. HELMS thought that the circumstances surrounding the pairing of HELMS and SCHWARTZ for the flight to Lebanon was the result of a quick decision made on the part of HAYES to fly the flight with his friend SCHWARTZ in lieu of finding a more seasoned pilot on a day at a time of year when few pilots were available, Christmas. HELMS further indicated that it was not company policy to place two relatively inexperienced Learjet pilots together as part of the same crew. On the contrary, it was typical that HAYES would fly with one of the more seasoned captains, for example, LINDEN.  In fact, LINDEN and HAYES had just completed an international flight across the Atlantic to Russia just one week prior to the accident.  HELMS believes that this accident was in part, caused by, the pairing of two relatively in-experienced Learjet pilots. [34]

 

 

4.8.         Reconstruction of flight approach profiles

 

In an attempt to recreate the flight conditions and probable flight track of the Learjet during the VOR 25 approach, Bill Shea, an experienced Learjet pilot was retained to perform approach profiles of the flight in a FAA-approved, Level-D, flight simulator. The simulator was programmed with the following assumptions:

·        The flight crew was flying at 200 KIAS.

·        The winds were 250 degrees (magnetic) at 60 knots.

·        The crew attempted the procedure turn in the directions as indicated on the VOR RWY 25 approach plate.

·        The point of last known radar contact was 6nm NE of LEB VOR.

 

The simulator experiments were conducted as follows:

·        Experiment 1 – Initiation of the procedure turn at the point of last known radar contact.

·        Experiment 2 – Initiation of the procedure turn 1 minute after the point of last known radar contact.

·        Experiment 3 – Initiation of the procedure turn 2 minutes after the point of last known radar contact.

 

The purpose of these experiments is to study and analyze the resultant “character” of the procedure turn.[35]

 

As with all instrument approach procedures, the approach profile has a circular boundary in which all of the approach procedures are to be completed. This boundary is typically a circle with a radius of 10nm and is centered around the primary navigation fix which is used in the approach procedure. All of the minimum descent altitudes and controlling altitudes used on the approach are derived from the protected area defined by the approach boundary. Traveling outside of this boundary while executing a instrument approach procedure is not authorized. This is exemplified by the words “Remain within 10NM” as they appear on the NOAA approach plate profile view for the VOR 25 approach at LEB. [36]  Obstruction clearance is guaranteed within the bounded area providing the controlling altitudes prescribed by the approach are adhered to by pilots. The VOR 25 approach at LEB authorizes pilots to fly no lower than 4300’ MSL between 6.6 NM from the VOR to the outer limit of 10 NM. Beyond that, the minimum safe altitude for the area northeast of the approach is 5900’ MSL. [37]

 

CONCLUSIONS:

 

·        The result of experiment 1 showed the extremity of the procedure turn to be 15 NM.[38]

·        The result of experiment 2 showed the extremity of the procedure turn to be 19 NM. [39]

·        The result of experiment 3 showed the extremity of the procedure turn to be 23 NM.[40]

·        The results of all of the experiments indicate that the aircraft was well beyond the 10 NM protection established for the approach.[41]

·        Analysis of the simulator data suggests that it is plausible that the aircraft traveled as far as Carr Mt in Warren NH and possibly beyond. There is significant terrain above 2900’ MSL (Procedure turn inbound altitude) in the suggested area. It is probable that the aircraft is in that general area, most likely in the area of the extended final approach course to RWY 25. [42]

·        Bill Shea’s opinion on this analysis provides insight to the potential actions of the Learjet’s flight crew.

As a high time jet pilot and jet simulator instructor, it has been my experience to observe professional corporate flight crews to inadvertently maneuver beyond the 10 NM protection zone during VOR approaches with as little as 10 knots of tailwind. Although the crews are incorrect by exceeding this protection zone, none the less, it happens more than one might expect.  I have never asked a crew to conduct a VOR approach with tailwinds of 60 knots, because it would generally be considered unrealistic, but my experience tells me that it will most likely end up with a violation of the protected airspace.  I have also observed flight crews to “proceed outbound” from the initial approach fix for as long as 2 minutes before initiating the procedure turn. Usually, this procedure is a hold over (technique) from the initial instrument training that the pilot obtained at an earlier point.  For a jet aircraft, this technique is poor, but the fact is pilots continue to utilize procedures that are developed for “slow” aircraft. It is possible that the crew utilized a time value of more than a minute. This coupled with the tremendous winds, indicate that [it] is very likely [that it] ended up east of where search efforts have been conducted. [43]

 

 


 

 

 

5.        Eyewitness Reports and Testimony

 

Over 200 eyewitness reports were collected by government agencies including New Hampshire State Police, New Hampshire Fish & Game Department and New Hampshire Civil Aeronautics Board between December 24, 1996 and January 15, 1996.  The reports are authored by various law enforcement officers responding to calls to collect data from eyewitnesses. These reports consist of individual testimony of citizens of New Hampshire, Maine and Vermont who relate:

·        Seeing a low-flying jet aircraft

·        Hearing a low-flying jet aircraft

·        Hearing a “crash”

·        Smelling fuel odors

 

The majority of the reports consist of testimony from individuals who heard a low-flying jet aircraft on or about December 24, 1996.  Others report seeing a jet airplane, flying at very low altitudes as far west as Topsham, VT and as far east as Lincoln, NH.  Still others report smelling strong odors of diesel fuel, similar to aviation kerosene, on the day of the accident and the day after as well as reports of hearing a crash or loud noise.  All of the reports span a time frame of 48 hours, sometimes more. In most cases, specifics about what was experienced (seen, heard, felt, etc), the direction of the aircraft, the description of the sound or aircraft and the time of the experience are substantially vague.  [44]

 

The eyewitness reports add an interesting and somewhat sensationalistic perspective to the disappearance to the Learjet. If one were to examine all the reports and make speculative conclusions about their content, they would suggest that the Learjet did not crash in the 8 minutes and 7 seconds of time between the last recorded radar position and the attempt of ATC to raise the flight on frequency but that it continued to fly for sometime after that, traveling as far east as Lincoln, NH and as far west as Topsham, VT upwards of two hours after it’s last known radar contact.  If one we’re to assume that ALL of the eyewitness reports were essentially substantiated facts of the track of the Learjet and not that of another aircraft, it still remains unlikely and improbable that a chronological sequence reconstructing the track of the flight and the probable location of the crash site could be produced.  This would additionally assume that A) After the last voice communication received from the flight crew at 9:59:26, the flight crew was unable or unwilling to communicate.

B) Although the aircraft was never again detected on surveillance radar, either by discrete beacon code, emergency discrete code or primary target reflection, it continued to fly for some time after it’s last recorded radar position at 10:01:47 at an altitude below the base radar coverage for the area (4700’ MSL). C) The flight crew decided to fly VFR in IFR conditions and was able to fly and maneuver the Learjet at airspeeds of 200-250 knots at low altitude, in unfamiliar terrain, in marginal visibilities and without assistance from ATC or radio navigation.

 

Given the limited visibility in the area that morning, the mountainous terrain around Lebanon and the fact the flight crew was piloting a high-speed jet aircraft, it is unlikely and statistically improbable that any of the above assumptions are true.

 

5.1.         Warren NH reports

 

Certain eyewitness reports have been reviewed and the individuals who reported them, re-interviewed to obtain additional details and to verify the consistency of the facts presented in the reports.  These reports are of specific interest due to the individual’s experience (what they observed), when they observed the experience and the location where the experience took place. 

 

One eyewitness report, that of Warren Stickney, was of particular interest to this investigation. STICKNEY’s report was unlike any other eyewitness report received regarding the missing Learjet because it involved hearing a jet aircraft at very close range, hearing a crash, feeling a vibration of the impact and smelling diesel fuel odors all at the same location and within a relatively short period of time.  No other eyewitness report provides these clues together at the same location, witnessed by the same person.  As a result and in light of the facts supporting the last known position of the jet and it’s probable flight track, STICKNEY’s testimony is of significant value to potentially locating the crash site of the Learjet.

 

I interviewed Warren Stickney on 2/10/98 at his residence on Beech Hill Road, Warren NH.  STICKNEY related the following:

On 12/24/96 during the day between 9:30-10AM he was smoking on his rear deck of the house which faces south/southeast.  He heard a jet aircraft from the north/northwest. Jet engine sounded like a roaring noise. He heard this sound for 1-3 seconds and then heard a “tremendous impact” which lasted an instant and then felt a slight vibration from the deck seconds later. STICKNEY indicated he was sitting on the railing of the deck. Several seconds later he heard another impact on the east side of beech hill road which wasn’t as loud as the first impact.  The east side of Beech Hill Road slopes to a lower altitude where a valley is formed by Beech Hill on the west and Carr MT on the east. Carr Mt is approximately 3-4 miles east of STICKNEY’s house.  On XMAS AM, at approximately the same time, STICKNEY was standing on rear deck again and it smelled like he was standing in a pool of diesel fuel.  He checked with neighbors that day and no one else on road had heard anything.

STICKNEY’s house sits on the southern exposure of Beech Hill at approximately 1200’ MSL, ˝ mile south of the summit 1600’ MSL. He has a clear and unobstructed view of CARR MT, Ames MT and the south exposure of the valley towards Wentworth. Beech Hill road passes North/South to the east of his house. Of additional significance is the fact that STICKNEY’s house sits 3 NM north of the extended center line of the VOR 25 approach course (the 66 degree radial of the LEB VOR). STICKNEY further related that the weather on 12/24/96 was low clouds, low ceiling, indicated he couldn’t see CARR MT or AMES MT, 3 miles away. Precipitation was drizzle w/ snow on ground.  Very cold.  STICKNEY related the weather on 12/25/96 was overcast, low ceiling, low visibility, light wind and possibly light snow. [45]


 

 

 

5.2.         Fuel Odor Reports

 

Several reports of fuel odor were reviewed during the investigation of the eyewitness reports. These reports represent the only, potential, physical evidence of a airplane crash. As such, they are an important aspect of the search and locating efforts underway to find the crash site. Of particular significance is the report of STICKNEY who related smelling, very strongly, the odor of diesel fuel the morning of December 25, 1996 at his residence. Facts concerning this event were analyzed by the Dartmouth group,

…Warren Stickney reported smelling diesel fumes as if he was “standing in a pool of diesel.” According to the research published by the National Science Foundation, diesel fuel, which has a similar smell to kerosene and Jet-A (the fuel in N388LS), has a threshold perception value 100% of the time at approximately 1 PPM. [46]

 

The Dartmouth group, through their fuel vapor analysis, attempts to provide a scientific conclusion to the questions raised about the location of the source of fuel. Because of the significant number of assumptions required to complete the fuel vapor equation and due to the inability to ascertain accurate data for this analysis, it is difficult, if not impossible, to pinpoint with any accuracy, the location of the source of the fuel smell.

 

Errors … include the fact that the terrain is not flat, the wind velocity may have been greatly reduced by the terrain, and the wind may not have been at a constant velocity during this time. Also, the source rate for the fuel vapor may not have been a constant and the wind was almost certainly channeled through the mountains causing the vapors to travel indirectly from the source to the eyewitness. … this model assumes that all the fuel onboard the aircraft at the time of the incident evaporated from one source point over the following 48 hours. [47]

 


 

 

CONCLUSIONS:

 

·        Eyewitness reports are not conclusive factual statements. They often provide opinion in addition to information about what an individual observed. In using this important area of data, opinions, comments, suggestions or speculation by the witness should be tempered and separated from the essential facts they are reporting.

·        Eyewitness reports currently do not provide substantial factual data as to the probable cause of the accident due to their subjective nature of involvement, the existence of vague details in most of the reports and the inability of witnesses, due to weather or other natural phenomenon, to positively identify what they heard or saw as being the Learjet.

·        With very few exceptions, the eyewitness reports do not, specifically, support or corroborate known facts regarding the disappearance of the Learjet.

·        With regard to Warren Stickney’s report, it appears to be of significant relevance and value as a result of the geographic position of the report, contents of what was reported and the time frame of the observations. This single report corroborates facts regarding the flight; that the flight continued east on the extended approach course, in the direction of last known radar contact. When compared with other eyewitness reports in the Warren and Wentworth area of observations (visual sightings) recorded at approximately the same time, it suggests a plausible and probable assumption that the aircraft over flew the area shortly after it disappeared from tracking radar.

·        With regard to the fuel smell reports, no specific conclusion can be made as to the location of the source of the fuel, that presumably to be the aircraft, due to the lack of data concerning wind direction, velocity and airflow over the specific geography at the observed location. Only more general conclusions can be inferred by the fuel vapor analysis, that being, the source of the fuel was located within 6.6 statute miles upwind of the eyewitness report, and not more than 7 miles across the wind left or right of South southwest. [48]


 

 

 

6.        Findings of Contributing Factors

 

Several factors have been identified as contributing to the probable cause of this accident.

 

·       Failure of the flight crew to recognize and compensate for the strong wind aloft during the approach phase of the flight.

·       Failure of the flight crew to properly brief and conduct the planned approach(s).

·       Failure of the flight crew to maintain situational awareness as to their exact location relative to the airport and navigation aids they were using to conduct the instrument approaches.

·       Failure of the PIC to appropriately manage flight critical tasks in the cockpit.

·       Improper use of GPS navigation instrument by the flight crew.

·       Failure of the flight crew to maintain minimum safe altitudes and premature descent from published approach altitudes during the approach.

 

1.  Failure of the flight crew to recognize and compensate for the strong wind aloft during the approach phase of the flight.

 

The flight crew failed to recognize and compensate for the strong wind conditions aloft during the approach phase of both the ILS 18 approach and the VOR 25 approach as is evidenced by the NTAP radar and voice recording transcripts.

 

When the airplane was 5 miles east of BURGR intersection, tracking southbound to the LEB VOR, the pilot radioed, ‘ah, and tower, Lear three eight eight lima sierra, we’re BURGR inbound, we’re not getting a localizer.’ [49]

 

This statement clearly shows that the flight crew was significantly east of their presumed position.  Given that the recorded wind condition at altitude was 260 degrees at 70 knots and the inbound course for the ILS 18 approach is 187 degrees, it is evident that a 73 degree crosswind component of 70 knots existed during this maneuver.

 

Similarly, the flight crew failed to realize the effects of the wind condition aloft when they attempted to conduct the VOR 25 approach transition. While attempting to join the 66 degree radial of the LEB VOR, the aircraft would have experienced a direct tailwind of 70 knots. At it’s last known radar position, approximately 7 miles northeast of the LEB VOR, the aircraft was still not established on the outbound radial.

 

Reconstructed profiles of the VOR 25 approach suggest that it was probable the flight crew could not have completed the approach within the protected airspace but instead proceeded outside of the 10 NM approach boundary for some undetermined distance to complete the PT.

 

 

2.  Failure of the flight crew to properly brief and conduct the planned approach(s).

 

Upon reviewing the radar NTAP data and voice communication transcripts it is evident that the flight crew did not properly conduct either approach that was attempted during the flight. The NTAP radar plot shows that the aircraft never properly intercepted the ILS 18 glidepath or glideslope and in fact the flight crew never received proper glideslope or glidepath indication due to the aircraft’s position relative to the ILS approach corridor.

 

When the airplane was 5 miles east of BURGR intersection, tracking southbound to the LEB VOR, the pilot radioed, ‘ah, and tower, Lear three eight eight lima sierra, we’re BURGR inbound, we’re not getting a localizer.’ [50]

 

Shortly after, although the flight crew was cleared to perform the published missed approach procedure for this approach, they never did so. Instead,

… the airplane then descended from 4,700 feet to 4,200 feet and continued to the southeast… [51] in a direction opposite to that prescribed by the missed approach instructions.

 

The pilot was later cleared to the LEB VOR at or above 4,700 feet and for the VOR 25 approach to LEB. The airplane was about 8 miles southeast of the LEB VOR when the pilot radioed ‘…were ah five miles to the ah southeast of the VOR.’ About two minutes later, the airplane was about 1 mile southeast of the VOR when the pilot radioed ‘Lear three eight eight lima sierra is VOR outbound.’ [52]

 

This last transmission occurred at 9:59:23 local time. The aircraft was tracked on radar until 10:01:47. [53]

 

The last recorded radar data on the flight revealed the airplane was 6.5 NM northeast of the LEB VOR.  [54]

 

The position of the aircraft in relation to the VOR when the flight crew is attempting to establish themselves on an outbound course of 66 degrees as prescribed by the VOR 25 approach procedure is consistent with the significant quartering tailwind they were experiencing at altitude.

 

 

3.  Failure of the flight crew to maintain situational awareness as to their exact location relative to the airport and navigation aids they were using to conduct the instrument approaches.

 

 

Upon reviewing the radar NTAP plot and voice recording transcripts, it appears that the pilots we’re situationally disoriented as early as their transition to the ILS 18 approach. The flight crew’s reliance on the GPS unit for position as well as distance information, the existence of a strong southwesterly flow aloft and the mistaken assumption on the part of the flight crew that the airport and VOR we’re co-located are assertions which are not definitively factual but are probable after examining the known facts of the accident. It has been established that HAYES was well familiar with the GPS unit and historically used it readily during his flights in the Learjet. [55] The IFR flight plan filed by SCHWARTZ on the morning of December 24, 1996 indicated a final destination for the flight of Lebanon Airport with a initial approach fix of LEB (the Lebanon VOR). The flight crew had filed and been cleared to fly direct to Lebanon.

 

According to Boston Air Route Traffic Control Center (ARTCC) communication tapes and radar data, 7 minutes after takeoff from Bridgeport, CT, ARTCC cleared the Learjet direct to Lebanon when able. [56]

 

1427:01 R47    Lear eight lima sierra proceed direct to

              Lebanon when able 

1452:54 N388LS cleared direct Lebanon ah three eight lima [57]

 

Unlike VOR navigation, GPS navigation does not rely upon ground-based radio signals but instead determines exact position through tri-angulation by reference to satellites in orbit. One large disadvantage of VOR navigation is that aircraft must be within sufficient distance of the ground-based antennae to properly receive and use the signal for navigation. Typically, this distance is 70 miles or less. [58] GPS does not suffer from this problem and it is feasible and possible to navigate around the globe solely by using GPS navigation. The distance between Bridgeport, CT airport and Lebanon, NH airport is 189 NM. The flight crew could not possibly have been receiving appropriate navigation signals from the LEB VOR from their position at 14:27:01 UTC. The crew accepted the direct clearance to LEB at this time and as a result of this and the facts established regarding the use of GPS on board the aircraft, one can conclude that the GPS unit was used to navigate to LEB VOR from the beginning of the flight. It can be concluded then, that the flight crew had programmed the GPS with a waypoint of the LEB VOR.

 

This fact is of significant importance and is one key contributing factor to the cause of this accident. The other was the erroneous assumption on the part of the flight crew that the airport and VOR are co-located when in fact they are 4.4 NM apart. Upon examination of the subsequent actions of the flight crew and the recorded track of the aircraft, it can be concluded that the flight crew did not perform a thorough pre-approach briefing but instead cursorily looked at the approach plate. This probability is exemplified by the fact that the NOAA approach plate profile for the ILS 18 approach at LEB is cluttered with a significant amount of information. As a result, it is not easily discernable that the airport and VOR are located 4.4nm from one another.  The actions of the flight crew clearly support the conclusion that they navigated to the airport using the GPS set with a waypoint that of the VOR and not the airport. Further, they prepared for the ILS 18 approach by programming the primary NAV radio to the localizer frequency of the approach however, initiated a transition to the ILS 18 localizer approach course using the GPS. The result of these assumptive actions on the part of the flight crew would result in exactly what transpired and was recorded on radar and voice transcripts of the flight. As is evidenced on the NTAP radar transcript, after turning south, the aircraft continued south on a co-linear nearly parallel course with the localizer approach course (magnetic heading of 187), tracking to the VOR, not the airport. Because of the flight crew’s erroneous assumption that the VOR and airport we’re co-located, they continued flying south believing they were appropriately situated on the localizer approach course when in fact they were on a parallel course 5 miles east of the approach corridor. The flight crew never corrected for this erroneous assumption during this approach, the missed approach or the subsequent VOR 25 approach. The flight crew never realized the error in navigation but assumed that the reason for their not receiving appropriate localizer signals for the approach was due to malfunctioning ILS equipment on the ground. Analysis of the NTAP radar and voice recording transcripts show that at the point in time when the flight crew announced they were over the initial approach fix, BURGR, they were actually 5 miles east and ˝ mile south of that position. As a result, due to the very precise nature of instrument landing systems and the narrow path in which aircraft must fly within to receive appropriate glideslope and glidepath signals, the flight crew were never in a position to receive localizer directional indications and possibly never received useable signals from the localizer. This, complicated by the fact that the flight crew may have received an outer marker beacon signal that from the NDB present on the VOR 25 approach and not of the outer marker beacon at BURGR intersection on the ILS 18 approach, added significant confusion as to their exact position. This is corroborated by the flight crew’s statements to ATC,

 

1450:54 N388LS ah and tower Lear three eight eight lima

              sierra we’re burger inbound we’re not

              getting the localizer

 

ATC responded,

 

1451:02 LC     Learjet eight lima sierra roger are you

              continuing with the approach or ah execute

              the missed approach present position your

              choice localizer’s in the green.

 

45 seconds passed and the aircraft traveled almost 2 NM. The flight crew’s reluctance to answer ATC’s query indicates a preoccupation in the cockpit. One can presume that the flight crew is attempting to determine what went wrong with the approach and what to do next.

 

ATC again calls the aircraft,

1451:43 LC     Learjet three eight eight lima sierra say

              intentions

1451:47 N388LS three eight eight lima sierra we’re going

              to execute the missed here ah we’re not

              receiving the localizer

1452:03 LC     Learjet eight lima sierra published missed

              approach contact boston center one three

              four point seven.

 

The flight crew’s confusion and disorientation continue with Boston Center controllers.

 

1452:51 N388LS and for Lear three eight eight lima sierra

              is with you on the missed

1452:54 R37    ah Lear three eight eight lima sierra roger

              and say your intention

1452:57 N388LS ah roger ah just confirm that frequency is

              one eleven point nine

1453:02 R37    no the tower is that what you’re looking for

              the tower frequency

1453:06 N388LS No to the localizer (frequency)

1453:10 R37    okay stand by

1453:17 R37    november three eight eight lima sierra fly

              the ah published missed approach ah

              procedure maintain five thousand for now

              I’ll get right back to you

1453:24 N388LS Roger five thousand on the published missed

1453:29 R37    okay the localizer

1453:35 R37    eight eight lima sierra the localizer is ah

              one one one point niner is the frequency for

              the localizer

1453:41 N388LS okay we’re unable to get it ah uhm stand by

              one.

 

The fact that the flight crew asked ATC to verify the localizer frequency for the approach, something which is not commonly done, especially by professional, commercial pilots, reiterates the fact they were situationally disoriented as to their exact position and unprepared to conduct the approach as evidenced by their unfamiliarity with significant or important approach data (like the localizer frequency) and inability to refer readily to information supplied on the approach plate.

 

 

 

A less significant contributing factor of this accident was the lack of appropriate radar coverage and access of surveillance or approach radar by local tower controllers at Lebanon Tower. Due to the fact that tower controllers at LEB tower do not have BRITE, a remote console providing radar position data of aircraft in the area, the controllers never knew the aircraft’s exact position and could not have provided the flight crew assistance or even recognized the fact that they were so far off course.

 

The assumption that the airport and VOR were co-located further contributed to the flight crew’s inability to properly conduct the VOR 25 approach. Because of this, during any portion of the VOR 25 approach, they would have been 4.5nm further east of their presumed location. This assumption, in addition to the fact that the aircraft was nearly 7nm northeast of the VOR and still not established on the prescribed outbound 66 degree radial for the approach at it’s last known position, caused the flight crew to complete the remaining portion of the approach well outside of the authorized airspace. Analysis of the existing weather conditions indicated that a thick stratus cloud layer existed with a base at 1800’ MSL and top of 4000’ MSL. Given this fact, the flight crew would have experienced satisfactory visibility (more than 3 miles) when above the cloud layer. As is evidenced by interviews of pilots flying in the area at the same time, low mountain tops we’re covered in clouds and terrain that was higher than 4000’ MSL was visible above the cloud layer. The flight crew would not have sufficient forward visibility to see and avoid terrain however when they began a descent into the cloud layer from 4800’ MSL. As corroborated by NTAP radar transcripts, the aircraft proceeded outbound from the VOR on a northeast heading for some point in time.  If we are to assume that the flight crew attempted to conduct the VOR 25 approach as prescribed by the approach plate, it can be concluded that they initiated a procedure turn and at some point in time descended to 4300’ MSL and then again to 2900’ MSL. 

 

 

4.  Failure of the PIC to appropriately manage flight critical tasks in the cockpit.

 

 

The PIC HAYES failed to familiarize himself with the planned approaches even though he was the non-flying pilot. In addition, he failed to appropriately monitor and continually review the actions of the flying pilot, SCHWARTZ, a practice which is common in commercial operations. Similarly, the SIC, SCHWARTZ failed to recognize the errors in navigation being introduced by PIC HAYES which culminated in conducting the instrument approaches incorrectly. Both pilots failed to independently assert their opinions to one another about what was transpiring during the approaches and neither recognized the grave errors in navigation that resulted. Cockpit resource management of critical flight tasks was not performed. As a result, the several contributing factors of this accident proved to overwhelm the flight crew.

 

 

5.  Improper use of GPS navigation instrument by the flight crew.

 

 

As was shown in previous sections, the flight crew improperly relied upon the GPS navigation unit to attempt to establish the aircraft on the localizer approach course. If the crew had used established methods for intercepting the localizer approach course, that of relying on the localizer radio beacon instead of an independent navigation instrument, they would have potentially, readily realized how far off course they were.

 

 

6.  Failure to maintain minimum safe altitudes and premature descent from published approach altitudes during approach.

 

The reconstruction experiments of the Learjet’s VOR 25 approach and the NTAP radar transcripts of the Learjet’s last known position indicate that it was probable and likely that the flight crew was unaware of the fact they we’re proceeding outside of the protected airspace boundary for the approach. Assuming this was true, the flight crew then proceeded for some undetermined distance outside of the 10 NM protected airspace ring to conduct the PT for the approach. It would be expected then, that they would, at some point, make a descent from 4300’ MSL to the next step down altitude of 2900’ MSL on the approach. It is probable and likely that the flight crew descended to 2900’ MSL prematurely either during the PT maneuver or just after it when established on the inbound course of the approach but well outside of the 10 NM protected airspace ring which guaranteed them obstruction clearance at that altitude.

 

 

 

7.        Determination of Probable Cause

 

 

A significant amount of time and effort was expended in gathering and performing analysis of the data in this accident. Over 1000 hours of time was logged and 100 individuals were consulted, interviewed, or contributed for/to this report. Even though this report is a significant culmination of efforts, it does not represent the individual contributions of other volunteers or individuals who are independently performing similar studies of this accident. Significant computer analysis, both by flight simulator and sophisticated analytical computers were employed to answer many questions pertinent to determining the probable cause of the accident.

 

Even after examining all of the data and facts collected in the investigation of this accident, no one definitive factor or chain of factors can be demonstrated to conclusively prove what occurred to the aircraft and it’s crew. On the contrary, it is the purpose of this report to conclude, from vigorous study of all of the facts, what was probable or likely to have occurred to cause this accident.

 

In that vane, two potential, probable causes were initially identified. 

 

Loss of Control During Flight

 

A potential probable cause that was investigated was loss of control of the aircraft in flight and subsequent impact with terrain. Historically, loss of control accidents occur almost always as the result of two different contributing factors. 1) Engine failure during flight. 2)Aircraft encountering windshear or microburst during flight. [59]  There is no evidence of engine failure occurring on N388LS prior to it’s disappearance, either as a result of icing or malfunction of engine components. Loss of control of the aircraft and subsequent impact with terrain, as a result of the flight encountering clear-air turbulence, wind shear or other weather phenomenon although possible was not likely due to the lack of evidence of convective weather, typically associated with microburst, a highly localized, downdraft or updraft of high velocity, vertically moving air, normally associated with thunderstorms. In examining all evidence, the flight crew was in control of the aircraft at all times during several maneuvers (turns, climbs, descents). With the one exception of mis-navigation, the flight crew conducted the flight normally.

 

Loss of control of the aircraft by inducing an accelerated stall condition, for example, would only occur by the deliberate actions of the flight crew.  The significant number and sophistication of devices on board the Learjet which warn of and impede this critical flight attitude and the training and experience of the flight crew, [The PIC HAYES had over 700 hours in the Learjet][60] point to the fact that this is an unlikely cause of the accident.  In addition, as evidenced by the extensive weather and aircraft movement analysis, it appears the flight crew had descended into IMC while conducting an instrument approach. For most professional, commercial jet pilots, diligence, past training and prudence would dictate operating the aircraft well within the performance envelope especially in the Learjet, an aircraft which is known to be unforgiving. It is unlikely then, that the flight crew performed some significant, high performance or irregular flight maneuver (a steeply banked or tight turn typically the cause of most all accelerated stall situations) while they were in IMC and had no reference to the horizon or the ground. Such a maneuver is counter-intuitive and opposes all standard instrument training procedures. 

 


 

 

Controlled Flight Into Terrain

 

It is the conclusion of this report, based upon all known available facts, analysis of accumulated data and the related opinions of aviation safety experts, experienced Learjet pilots[61], flight instructors and other aviation professionals, that the probable cause of this accident was:

 

in flight collision with terrain during instrument meteorological conditions as a consequence of the flight crew’s completing an instrument approach procedure below prescribed minimum safe altitudes while maneuvering outside of the 10 NM protected airspace as prescribed by the approved approach procedure. 

 

This cause can be substantiated by all of the identified contributing factors to the extent that it was a likely and probable extension of the contributing events which lead, reasonably, to the conclusion of the accident.

 

 


 

Aircraft Equipment List


 

NTAP Radar Viewpoint


 

ILS 18 Approach at Lebanon


 

VOR 25 Approach at Lebanon


 

8.        Glossary

 

Abbreviations and Terms used in this report

 

ATC        Air Traffic Control(ler)

AGL        Above Ground Level. Refers to altitude above ground level.

BURGR      A navigational fix defined by the intersection of the 317 degree radial of the Lebanon VOR and the 45 degree bearing from the White River NDB. It is also the Outer Marker of the ILS 18 approach at Lebanon located 3.3nm from the runway.

DME        Distance Measuring Equipment

ELT        Emergency Locator Transmitter. A radio transmitter used to aid locating and recovery of downed aircraft.

FAA        Federal Aviation Administration. The federal agency responsible for regulating all private and commercial aviation within the United States.

GPS        Global Positioning System.  A navigation system used by pilots which uses satellites around the earth to precisely determine longitude, latitude and altitude position.

IFR        Instrument Flight Rules. Refers to the regulations which define the manner in which aircraft are flown during bad weather, limited visibility less than 3 miles and when pilots have no visual reference to the horizon or ground.

ILS        Instrument Landing System. A highly precise navigating system used for landing at airports when flying under IFR. The ILS provides an aircraft with precise information about its horizontal (glidepath) and vertical (glideslope) position relative to the runway. By flying along an ILS glidepath and glideslope, an aircraft can be landed without visual contact with the airport’s runway until the last few seconds of flight.

IMC        Instrument Meteorological Conditions. Describes flight conditions in which pilots have no forward visibility or reference to the horizon.

LEB        The three letter identifier for Lebanon Municipal Airport.

MSL        Mean Sea Level. Refers to altitude above mean sea level.

NM         Nautical Mile. One minute of latitude or 1.15 statute miles.

NTAP       National Tracking Analysis Program

NOAA       National Oceanic and Atmospheric Administration

NTSB       National Transportation Safety Board

PIC        Pilot in Command

PT         Procedure Turn.  The maneuver during an instrument approach procedure where a pilot performs a 180 change in heading in a manner prescribed by the approach procedure.

SIC        Second in Command

VFR        Visual Flight Rules. Refers to the regulations which define the manner in which aircraft are flown during good weather, visibility greater than 3 miles and visual reference to the ground.

VOR        Very High Frequency Omnidirectional Rangefinder. A radio navigation beacon which enables pilots to navigate through the air by following radio transmissions from ground-based antennae stations.

 

 

 


 

[1] NTSB (National Transportation Safety Board), Memorandum “Procedures” from Chief, AS 20 to Regional Directors, Aug. 29, 1990.

[2] NTSB, “Report of the Proceedings, Aviation Accident Investigation Symposium, Apr. 2628, 19S,3,Springfield, VA”, NTSB/RP-8401 @ 165

[3] Federal Aviation Administration, Freedom of Information Act Request 1998-001445NE

[4] Federal Aviation Administration, Freedom of Information Act Request 1998-004279NE

[5] Federal Aviation Administration, Transcript of aircraft accident N388LS, Lebanon, NH, December 24, 1996.

[6] Ibid.

[7] Ibid.

[8] Ibid.

[9] Ibid.

[10] Ibid.

[11] Ibid.

[12] Ibid.

[13] Ibid.

[14] ARTCC Daily Activity Log of 12/24/96, Boston Center, Nashua, NH. FOIA request 1998-001445NE 10/15/97.

[15] Phone interview with Buddy McDonald, Quality Assurance Specialist, Federal Aviation Administration, Burlington, MA, 10/03/97.

[16] The Missing Learjet: Meteorological Report and Analysis, Evan B. Gillespie, SUNY Albany, 11/97.

[17] Ibid.

[18] Ibid.

[19] Ibid.

[20] Northeast Regional Climate Center, Cornell University, Ithaca, NY, September 17, 1997.

[21] Phone Interview with Bill Oakes, PIC of N800HS citation jet landing LEB on 12/24/96. 10/3/97

[22] Written transcript of flight to LEB on 12/24/96, Peter Knox, PIC of N1737E, 10/07/97.

[23] The Missing Learjet: Meteorological Report and Analysis, Evan B. Gillespie, SUNY Albany, 11/97

[24] Ibid.

[25] Ibid.

[26] NTSB Aviation Accident/Incident Database Report #NYC97FAMS1

[27] Telephone Interview with Lars Linden, Owner of N388LS, 9/9/98.

[28] Telephone Interview with Carol Helms, CEO, Aircraft Charter Group, 9/9/98.

[29] NTSB Aviation Accident/Incident Database Report #NYC97FAMS1

[30] NTSB Aviation Accident/Incident Database Report#NYC97FAMS1

[31] Phone Interviews conducted with Lars Linden, Carol Helms, Kevin Clark, Tom Garrity, Doug Thompson, 10/97

[32] Phone Interview conducted with Bill Case, Director of Maintenance-Aircraft Charter Group, 9/98.

[33] Phone Interviews with Lars Linden, 9/97-9/98

[34] Phone Interviews with Carol Helms, 9/97–9/98

[35] Report of flown approach profiles by Bill Shea, 9/98.

[36] NOAA Approach Plate for VOR RWY 25 Instrument Approach to Lebanon Airport, NE-1, 15 AUG 1996.

[37] Ibid.

[38] Conclusion from report of flown approach profiles by Bill Shea. 9/98.

[39] Ibid.

[40] Ibid.

[41] Ibid.

[42] Ibid.

[43] Report of flown approach profile simulations in LR-35 conducted by William Shea, Simuflite International Simulator Instructor, Lear Pilot with 5300 flight hours.

[44] Analysis of Eyewitness reports provided by New Hampshire State Police, 10/97.

[45] Interview with Warren Stickney, Beech Hill Road, Warren NH, 02/10/98.

[46] Missing Learjet Aircraft and Crew, Final Report, March 12, 1998, Jonas U Gustafsson et al, Dartmouth College.

[47] Ibid.

[48] Missing Learjet Aircraft and Crew, Final Report, March 12, 1998, Jonas U Gustafsson et al, Dartmouth College.

[49] NTSB Aviation Accident/Incident Database Report  #NYC97FAMS1

[50] NTSB Aviation Accident/Incident Database Report #NYC97FAMS1

[51] Ibid.

[52] Ibid.

[53] FAA, Boston ARTCC NTAP DATA, Flight track of N388LS, Learjet 35A, December 24, 1996.

[54] Ibid.

[55] Phone Interview conducted with Lars Linden, owner of N388LS and coworker of HAYES, 10/97.

[56] NTSB Aviation Accident/Incident Database Report #NYC97FAMS1

[57] FAA, Transcript of aircraft accident N388LS, Lebanon NH, December 24, 1996.

[58] AIM (Airman’s Information Manual), Jeppesen-Sanderson, Inc, 1998.

[59] NTSB Aviation Accident/Incident Database, Statistical and Summary analysis, S.Estey, 8/98.

[60] NTSB Aviation Accident/Incident Database Report #NYC97FAMS1

[61] Pilots who were consulted for their opinions in light of their significant experience and education in piloting Learjet aircraft: Bob Yarmey, Bill Shea, Bill Oakes, Rob Wermer, Lars Linden.

 

BACK TO MY RV BUILDER'S HOME

BACK TO BRIAN'S HOME