MIA97FA213

NTSB accident investigation · Gates Learjet 35A · Avon Park, FL · July 15, 1997

Accident · Minor injuriesField investigationFinal report
Date
July 15, 1997, 19:53 local (23:53 UTC)
Place
Avon Park, FL
Injuries
2 minor
Damage
Destroyed
Phase of flight
Landing
Aircraft
N19LHGates Learjet 35A
Weather
Visual (VMC) · Dusk
Status
Completed · report May 4, 1998
Report
Approved by Office Director
FAA report
19970715018569A
Case key
38148

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

a loss of engine power as a result of the thrust reversers being deployed and subsequent in-flight collision was wires. Factors in this accident were the pilot's disregard for procedures, and the improper use of the thrust reversers.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine powerLanding - aborted
All available runway - not usedPilot in command
Emotional reactionPilot in command
Procedures/directives - not complied withPilot in commandFactor
Aborted landing - initiatedPilot in command
Thrust reverser - deployed inadvertentlyCause
Reversers - improper use ofPilot in commandFactor
In flight collision with objectClimb
Object - wire,static
In flight collision with terrain/waterDescent - uncontrolled
Terrain condition - ground

Analysis

Witnesses near the airport saw the flight approach on a left base to runway 4, touchdown on the runway, and takeoff again. One witness, a pilot, said the airplane turned onto final to the 'south' (right) of the runway centerline.' The airplane made a 'sharp' turn to the left to realign with the runway center, slightly overshot the runway to the left, turned to the right 'sharply,' and touched down on the runway. The witness further stated, '...by the time the pilot was on the runway he had wasted approximately 1,200 to 1,500 feet of runway 4, they hit reverse thrusters [sic] and were on full bore till they crossed runway 27 and 9.' The witness saw heat come out of both engine thrust reversers, the nose gear touched down and then came up again. He then saw the airplane come off the ground about 30 to 40 feet, wobble left and right at a 'slow airspeed,' crossover a highway at a low altitude, right wing low, strike some wires, go into a field, and catch fire. The pilot said, when he touched down on the runway, the airplane seemed to 'lurch' to the side. He said at this point his airspeed was 126 knots. He elected to abort the landing, and applied full power. He said the engines would not develop thrust and he elected to land in a field less than 1/4 mile in front of him. Examination of the left thrust reverser revealed that the translator was in the deployed position, with the blocker doors fully open. Both the left and right pneumatic latches were found in the unlocked position. Examination of the right thrust reverser revealed that the translator was in the deployed position, with the blocker doors fully closed. The left pneumatic latch was found in the locked position. The right pneumatic latch was found in the unlocked position. The inboard sequence latches were found about 2 inches forward of full aft travel. The thrust reverser switch was found in the 'NORMAL' position. According to Gates Lear Jet Airworthiness Directive (AD) 79-08-01, '...to preclude inadvertent thrust reverser deployment and possible loss of aircraft control....,' the following limitations apply to all gates Lear Jet Model 35, 36, 35A, 36A, aircraft equipped with Aeronca Thrust reversers. According to the AD, Section I-LIMITATION; '....Thrust Reversers must not be operated prior to takeoff...Thrust Reversers must not be used for touch and go landings...After Thrust Reversers have been deployed, a visual check of proper door stowing must be made prior to takeoff...Operational Procedures in this Thrust Reverser Supplement are mandatory.' According to Lear Jet and FlightSafety International, the procedures that are taught to Lear Jet pilots in the use of thrust reverse and spoilers during landings are; '...pilots [are] to use thrust reverse only on full stop Lear Jet landings. Pilot are trained not to deploy spoilers or thrust reverse during touch and go's or during balked landings.' The pilot-in-command of N19LH at the time of the accident, told the NTSB investigator-in-charge (IIC) that he was 'aware' of the limitations on the Aeronca Thrust Reverser and he knew that once the Thrust Reverser was deployed that he was 'committed' to land. The pilot told the IIC that he knew of the limitations and that he was committed to land.

Factual narrative

History of flight

On July 15, 1997, about 1953 eastern daylight time, a Gates Learjet 35A, N19LH, registered to Orion Aircraft Sales Inc., crashed after an aborted landing at Avon Park, Florida. Visual meteorological conditions prevailed at the time and an instrument flight rules (IFR) flight plan was filed for the Title 14 CFR Part 91, positioning flight. The airline transport-rated pilot and commercial-rated copilot received minor injuries. The airplane was destroyed. The flight had originated from the Fort Lauderdale Executive Airport, Florida, the same day at 1917.

At 1853:56, the pilot of N19H, called the St. Petersburg AFSS (Automated Flight Service Station) to file an IFR flight plan. He was informed by the briefer that his flight plan data was entered into the system. The telephone conversation was ended at 1855:17.

The flight proceeded without incident, and at 1930:00, the flight was cleared to descend to 4,000 feet. A subsequent clearance to 3,000 feet was issued at 1937:27. The pilot cancelled IFR at 1938:28, and radar service was terminated.

Witnesses near the airport saw the flight circle once over the airport, approach on a left base to runway 4, touchdown, and takeoff again. One witness, a pilot, told the NTSB IIC (investigator-in-charge) that he observed the airplane turn onto final to the "south" (right) of the runway centerline." The airplane made a "sharp" turn to the left to realign with the runway center, slightly overshot the runway to the left, turned to the right "sharply," and touched down on the runway. The witness further stated, "...by the time the pilot was on the runway he had wasted approximately 1,200 to 1,500 feet of runway 4, they hit reverse thrusters [sic] and were on full bore till they crossed runway 27 and 9." The witness saw heat come out of both engine thrust reversers, the nose gear touched down and then came up again. He then saw the airplane come off the ground about 30 to 40 feet, wobble left and right at a "slow airspeed," crossover a highway at a low altitude, right wing low, strike some wires, go into a field, and catch fire.

The pilot in a statement to local police said, when he touched down on the runway, the airplane seemed to "lurch" to the side. He said, at this point his airspeed was 126 knots. He elected to abort the landing, and applied full power. He said the engines would not develop thrust and he elected to land in a field less than 1/4 mile in front of him.

The accident occurred during the hours of dusk approximately 27 degrees, 35 minutes north, and 081 degrees, 31 minutes west.

Personnel information

Information on the pilot is contained in this report on page 3, under First Pilot Information. Information on the second pilot is contained in this report on Supplement E.

Meteorological information

Visual meteorological conditions prevailed at the time of the accident. Meteorological information is contained in this report on page 3, under Weather Information.

Flight recorders

The Universal model 30A cockpit voice recorder (CVR), was examined at the NTSB audio laboratory on July 23, 1997, and a transcript was prepared of 02:55 minutes of the 32:03 minute recording. Information and the transcript of the CVR are contained in this report, under Cockpit Voice Recorder, Factual Report of Group Chairman.

Wreckage and impact information

An examination of runway 4, revealed that there were no parts of the airplane found on the runway or the areas around the runway. A walk of runway 4 by the NTSB, FAA and parties to the investigation revealed that skid marks similar to a Learjet landing gear signature was found about 1,800 feet from the approach end of runway 4. There was no confirmation that the marks were from N19H, and no marks in the touchdown area could be identified as being from N19H. There were no marks observed on the runway that could be identified as going off the left or right side of the runway.

After leaving the runway the airplane traveled on a heading of 040 degrees about 1,000 feet and was seen by the witness striking a single power line, and cutting the line. Scrape marks from the right wing tip tank were found in the pavement of the road. The airplane was then seen impacting right wing first in a field behind a building, striking a tractor mower and continuing on a heading of 040 degrees shedding parts for about 450 feet. The airplane came to rest with the fuselage and nose of the airplane heading north.

Examination of the wreckage at a hanger at the Avon Park Airport, revealed that the left wing was about 60 percent consumed by fire. The leading edge had a section of cable lodged in it at about wing station (WS) 177.

The right wing had displayed fire damage at both the center section and the outboard end. The right wing tip tank and wing extension separated at WS 181. The right tip tank fin was scratched and bent.

The fuselage had separated from the wing and was broken in two, about station 346.63. Wrinkling and damage was observed all along the fuselage.

Examination of the empennage revealed that the left horizontal and left elevator were bent down and under the horizontal stabilizer. The left forward engine beam failed at the fuselage with about 12 inches of the upper cap staying with the mount and engine. The mount displayed evidence of bending moments in both the up and down directions. The right forward engine beam was broken at the fuselage, and displayed a downward load at the fracture surface.

The left engine was attached to the airplane, but had come to rest on the right side of the fuselage, and was being held in place by wiring and hoses. Observation of the engine revealed signs of rotation on the fan blades.

The right engine had separated during the impact sequence. Observation of the engine revealed signs of rotation on the fan blades.

The airplane was equipped with two Aeronca Thrust reversers. Examination of the left thrust reverser revealed that the translator was in the deployed position, with the blocker doors fully open. The translator was found 1 1/2 inches to 3 inches from full aft travel. Both the left and right pneumatic latches were found in the unlocked position. The inboard sequence latch was found about 3 inches forward of full aft travel. The latch hammer was engaged. The outboard sequence latch was found about 1 1/2 inches forward of full aft travel. The latch hammer was disengaged. Both the inboard and outboard flex drive cable cores were found in an unserviceable condition. The pneumatic actuator was cranked by hand with the flex drive cables removed. The actuator motor was not seized and appeared to be operational.

Examination of the right thrust reverser revealed that the translator was in the deployed position, with the blocker doors fully closed. The translator was found 1 to 2 inches from full aft travel. The left pneumatic latch was found in the locked position. The right pneumatic latch was found in the unlocked position. The inboard sequence latch was found about 2 inches forward of full aft travel. The stop housing was broken and found in the lower access area of the thrust reverser body. The attaching screws, sliding blocker, pivoting blocker and housing fingers were still attached to the beam. The latch hammer position could not be determined. The outboard sequence latch was found about 1 inch forward of full aft travel. The latch hammer was disengaged. The inboard flex drive cable core was found sheared at the upper pinion gear box end, and was in an unserviceable condition. The outboard flex drive cable core was found in an unserviceable condition. The pneumatic actuator was cranked by hand with the flex drive cables removed. The actuator motor was not seized and was operational. The lower inboard operating rod displayed an "S" shaped bend. The corresponding yoke base was also bent.

The

Aircraft

Registration
N19LH
Reported as
Gates Learjet 35A
Category
Airplane
Serial number
279
Airframe hours
13,726
Engine
Garrett 731-2-2B, 3,500 lbs thrust, turbo fan
Damage
Destroyed
Fire
On-Ground
Flight
Positioning · Part 91
Registered owner
Orion Aircraft Sales Inc.
Airworthiness certificate
Standard, Utility
Last inspection
Continuous airworthiness · February 6, 1997 · 190 hours before
Departed
FXE · Ft Lauderdale, FL
Destination
AVO
Flight plan
IFR
Airport
AVO · Avon Park Municipal, runway 4, 4,000 × 75 ft, asphalt

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
62
Certificates
Flight instructor, Airline transport
Airplane ratings
Multi-engine land, Single-engine land
Instrument ratings
Airplane
Medical
Class 1, Valid Medical--w/ waivers/lim
Seat
Left
Flight hours
20,076 total · 1,500 in this make and model · 19,000 as pilot in command · 194 in the last 90 days · 55 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Dusk
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
77 °F, dew point 70 °F
Altimeter
30.00 inHg
Observed at
GIF, 35 nm away

Docket · 23

The files NTSB released with the investigation on March 3, 1998, on NTSB’s docket system: statements, records, photos and specialists’ reports. 5.2 MB in all.

Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1Item 1 · .PDF · 432 KBSupplement CItem 2 · .PDF · 403 KBSupplement DItem 3 · .PDF · 541 KBSupplement EItem 4 · .PDF · 117 KBSupplement KItem 5 · .PDF · 424 KBMaps or Charts of Accident Area, Wreckage DiagramsItem 6 · .PDF · 46 KBCockpit Voice Recorder - Factual ReportItem 7 · .PDF · 308 KBMaterials Laboratory - Factual ReportItem 8 · .PDF · 61 KBWitness StatementsItem 9 · .PDF · 154 KBTranscript of Radio CommunicationsItem 10 · .PDF · 178 KBHighlands Co. Sheriff's Office ReportItem 11 · .PDF · 1.1 MBStatement of Party Representatives to NTSB InvestigationItem 12 · .PDF · 74 KBRelease of Aircraft Wreckage, NTSB Form 6120.15Item 13 · .PDF · 81 KBMemorandum From Flight Safety InternationalItem 14 · .PDF · 104 KBPhoto 1. General view of the crash site. Photo taken to the east in the direction of travelItem 15 · .PDF · 130 KBPhoto 2. General view of the crash site. Photo taken to the west opposite the direction of travel.Item 16 · .PDF · 109 KBPhoto 3. The right wing is shown in the foreground of the photo. The arrow points to the wire that witnesses said they saw the airplane's right wing strike.Item 17 · .PDF · 167 KBPhoto 4. Arrow No. 1 points to the wire shown in photo No.3 Arrow No 2. points to the runway at Avon Park Airport.Item 18 · .PDF · 116 KBPhoto 5. Right tip tank.Item 19 · .PDF · 134 KBPhoto 6. Wire marks found on the right tip tank.Item 20 · .PDF · 111 KBPhoto 7. Left Engine. The arrow points to the thrust reverser translator in the deployed position.Item 21 · .PDF · 159 KBPhoto 8. Right engine. The arrow points to the thrust reverser translator in the deployed position.Item 22 · .PDF · 155 KBPhoto 9. Right engine. The arrow points to the thrust reverser blocker doors in the fully closed position.Item 23 · .PDF · 134 KB

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.