Heard about a stupid accident? This is it - Curt Lewis

Multiple Failures Put Learjet 35A into the Atlantic

I thought the days of poorly trained captains and seat-warming copilots were long gone in turbine operations - at least those conducted in the U.S. But it would seem there are still operators who are not especially particular about who's in the cockpit, or their level of competency in the face of unexpected situations.

This month we'll take a quick look at the loss of a Learjet 35A (XA-USD) fatal to all four occupants on Nov. 19, 2013, when it crashed into the sea off the Fort Lauderdale, Florida, coast just 3 min. or so after takeoff.

 

The NTSB determined the probable cause of the accident was "the pilot's failure to maintain control of the airplane following an inflight deployment of the left engine thrust reverser." Further contributing to the accident, it said, "was the flight crew's failure to perform the appropriate emergency procedures, the copilot's lack of qualification and capability to act as a required flight crewmember for the flight, and the inflight deployment of the left engine thrust reverser for reasons that could not be determined through post-accident investigation."

The airplane had just completed an air ambulance flight for Air Evac International from San Jose, Costa Rica, to Fort Lauderdale-Hollywood International Airport (FLL) and was repositioning back to its base in Cozumel, Mexico. Weather at FLL included few clouds at 2,500 ft. and a scattered layer at 6,500 ft. The wind was calm and visibility was 9 mi. The temperature was 23C, the dew point was 22C, and the altimeter setting was 29.93 in. of mercury.

The Flight 

 Investigators used FAA ATC voice and radar recordings to determine the Learjet's track and timeline. The airplane departed Runway 10 at FLL at about 1950 and climbed straight ahead. When it reached an altitude of about 2,200 ft. and a groundspeed of 200 kt., the copilot requested radar vectors to return to the runway due to an "engine failure." The controller directed the flight to maintain 4,000 ft. and turn to a heading of 340 deg. The copilot replied, "Not possible" and requested a 180-deg. turn back to the airport. The controller acknowledged, but the airplane continued a gradual turn to the north as it slowed and descended.

Two minutes later, the copilot declared a "Mayday!" and again requested vectors back to FLL. During the next 3 min., the copilot requested vectors to the airport multiple times. While the copilot requested, received and acknowledged increasingly sharper and tighter turns to the southwest from ATC to return to the airport, the airplane continued its slow turn and descent to the north. During the 2 min. following the copilot's declared intention to return to FLL, the airplane descended to 900 ft. and slowed to 140 kt. as it flew northbound, parallel to the shoreline and away from FLL.

At 1955:15, the copilot reported the airplane was ". . . 200 ft. over the sea." After that, there were no intelligible transmissions received from the airplane, and communications with the airplane were lost.

A search began immediately, but there was no evidence of survivors. Some floating wreckage was recovered by the U.S. Coast Guard. It showed impact damage but no evidence of fire. The main wreckage was located on the ocean floor on Dec. 3, 2014. 

The wings were separated from the fuselage, and the outboard section of the left wing was missing. The left and right wingtip tanks were detached from the wings. Both ailerons were identified, and one wing flap was found at the retracted position. Both main landing gear were retracted.

On the throttle quadrant, the left power lever was found past the maximum position and damage to the forward stop was consistent with over-travel. The right lever was found one-half inch from its maximum travel. There was no visible damage to either the idle or cutoff stops.

The thrust reverser control panel and panel chassis were deformed by impact forces. The internal electronic components were corroded and/or coated with dried materials indicative of immersion in salt water. The UNLOCK, DEPLOY and BLEED VALVE annunciator light assembly for both left and right engines appeared intact. The NORMAL/EMERGENCY STOW switch on the thrust reverser control panel was found intact in the control panel and in the NORMAL position.

The engine N2 rpm gauges indicated 96.8% on the left engine and 96.5% on the right. The engine turbine temperature gauges indicated 781C on the left engine and 780C on the right. The engine fan gauges indicated 89.2% on the left engine and 89.8% on the right. It would seem the engines had been operating at near maximum thrust. 

Thrust Reverser System

 Photographs taken of the submerged wreckage before its recovery from the ocean floor showed that the left engine's thrust reverser and blocker doors were not in the stowed position. Examination of components from both thrust reverser systems (left engine and right engine) after recovery indicated that the components sustained impact- and seawater-immersion damage. This damage precluded testing for electrical, pneumatic and mechanical continuity.  

Examination of the left engine's thrust reverser system components found that the upper blocker door was attached to the reverser and was in a partially deployed position. The lower blocker door was found hanging from one of its tension links. The lower blocker door's rod arm was missing a section of its clamping arm, and the pivoting pins were broken. The lower blocker door showed a gap between the door skin and door pan with a bend at the forward edge near the gap. Areas of paint and skin on the left engine nacelle skin and body structure forward and aft of the cascade exhaust showed discoloration and scorching, with some paint blistered or missing. The entire perimeter of the outer fan duct behind which the blocker doors stow (when the thrust reverser was stowed) was missing.

Examination of the right engine's thrust reverser system components found that the upper and lower blocker doors were in the stowed position. There was no visible damage or interference observed between the blocker doors and the surrounding structure. There was no evidence of heat damage on the engine nacelle outer skin or paint. 

The Pilots 

 The wreckage examination (and later bench testing) indicated clearly that the left reverser had deployed in flight. The fact that the airplane ended up in the water suggested that something went very wrong in the cockpit. 

Both pilots were employed by Vuela SA de CV, which was an independent company that "leased" the pilots to Aero JL SA de CV. Both companies were owned and operated by the same individuals.

The pilot held a Mexican commercial pilot certificate with ratings for airplane single-engine, airplane multiengine land and instrument airplane, and an ATP and type ratings in Learjets and the Gulfstream GI. The operator told investigators the pilot had accrued 10,091 total hours of flight experience, of which 1,400 hr. were in the 30-series Learjet. 

On July 5, 2013, the operator issued the pilot a certificate of training for 8 hr. of crew resource management. On the same day, he was issued another certificate for an additional 8 hr. of instruction on controlled flight into terrain.

The copilot held a commercial pilot certificate issued by Mexico, with ratings for airplane single-engine, airplane multiengine land and instrument airplane. The copilot's total flight experience could not be reconciled. Documents provided by the operator suggested the copilot had accrued an estimated 1,243 total hours of flight experience, of which 29 hr. were in the Learjet 35. 

According to company records and a resume, the copilot began flying Learjets for the Vuela SA/Aero JL organizations on May 1, 2013. At that time, the copilot declared 1,206 total hours of flight experience, of which 82 hr. were "observer" time in Learjet 25s. From the day of employment to the day of the accident, the copilot accrued 37.16 hr. of flight experience in Lear 25/35 airplanes.

A certificate stamped "General Technical Department of Licenses," which was forwarded by the operator to the NTSB, suggested the copilot accrued 175 hr. in the Learjet 35A between July 4, 2013, and Oct. 30, 2013; however, his total documented flight experience increased only 29 hr. over the same time period.

On Aug. 20, 2012, the copilot received a diploma for classroom instruction received for the Learjet 20 series airplanes from a technical training school in Mexico that had neither airplanes nor flight simulators. There was no evidence that the copilot completed any training or practical tests in a Learjet airplane or flight simulator.

On July 5, 2013, the operator issued the copilot a certificate of training for 8 hours of crew resource management. On the same day, he was issued another certificate for an additional 8 hours of instruction on controlled flight into terrain.

Pay records for the pilot and copilot show identical hours, deductions, and pay over several consecutive pay periods. The pilot and copilot had flown together on three occasions before the accident flight. The accident flight was their first flight together in the United States.

The Safety Board said a search of student records by "two prominent Learjet training vendors in the United States" revealed no records of simulator flight training or attendance by either the pilot or copilot. Emergency procedure training for an inflight deployment of a thrust reverser could be performed only in an appropriately equipped flight simulator.

The Director General of Civil Aeronautics (DGAC) for the government of Mexico examined the pilot and flight training records for both pilots and summarized their findings for the NTSB report:

"Both the pilot and copilot records showed inconsistencies on the verifications of training and certifications based on the way official government stamps and certifications were displayed over, and with, the entries. They were copies, and did not represent entries properly certified by the Government of Mexico."

Some of the captain's experience and certifications were based on logbooks never presented. The copilot's records showed the training for the Learjet 20/30 series airplanes provided and conducted exclusively by the operator, Aero JL. Further, there was no "original foreign license and logbook," no "official license certificate" or DGAC file records to support a claim that the copilot had 1,243 total hours of flight experience.

According to the DGAC, the copilot had actually accrued only 206 total hours of flight experience. The copilot was evaluated by the DGAC in the airplane on May 2, 2013, and his performance during the practical test was found to be "unsatisfactory." 

The CVR

 The transcript of the cockpit voice recorder (CVR) certainly reflected the training situation just outlined.    

No checklists were called for, offered or used by either crewmember during normal operations (before or during engine start, taxi, takeoff) or following the announced inflight emergency. There were no challenge-and-response checklist callouts between the pilot and copilot at any time during the flight, no elements of crew coordination and no identification of the emergency.

After the "engine failure" was declared to ATC, neither crewmember asked for or offered the "Engine Failure" checklist, nor was there any attempt to complete an emergency procedure and then ask for a checklist verification of actions taken. The pilot asked the copilot for unspecified "help" because he did not "know what's going on" and he could not identify the emergency or direct the copilot in any way with regard to managing or responding to the emergency. At no time did the copilot identify or verify a specific emergency or malfunction, and he did not provide any guidance or assistance to the pilot.

According to Learjet, in the event of an inflight emergency, the typical convention was for the pilot flying to fly the airplane and take over communications with ATC. The pilot monitoring should then complete the appropriate checklist, while audibly announcing his actions as they are completed. The pilot flying was to verify these actions prior to completion. Although different flight departments may adopt their own procedures, there was no evidence that any crew coordination actions took place on the accident flight. 

Specifically, the Safety Board said, "Based on the wreckage evidence and data recovered from the left engine's digital electronic engine control [DEEC], the thrust reverser rocker switch was not placed in the "EMER STOW" position, and the left engine was not shut down.

"The DEEC data showed a reduction in N1 about 100 sec. after takeoff followed by a rise in N1 about 35 sec. later. The data were consistent with the thrust reverser deploying in flight [resulting in the reduction in N1] followed by the inflight separation of the lower blocker door [resulting in the rise in N1 as some direct exhaust flow was restored]. 

"Further, the DEEC data revealed full engine power application throughout the flight. Although neither flight crewmember recognized that the problem was an inflight deployment of the left thrust reverser, certification flight test data indicated that the airplane would have been controllable as it was configured on the accident flight. If the crew had applied the "engine failure" emergency procedure [the perceived problem that the copilot reported to the air traffic controller], the airplane would have been more easily controlled and could have been successfully landed."

Unwanted TR Deployment

 Manufactured in 1979, the accident airplane was powered by two Garrett (Honeywell) TFE731-2 turbofan engines. Its most recent continuous airworthiness inspection was completed Nov. 4, 2013, at 6,842 aircraft hours.   

The Lear was equipped with an Aeronca Inc. 45-1000 thrust reverser system. When reverse thrust was commanded from the cockpit during a landing roll, the thrust reversers operated to reverse the direction of the engine exhaust gases to assist with stopping the airplane on the runway. The thrust reversers were designed to deploy only when the squat switches were in the "weight on wheels" mode and the throttles were in the idle position. When activated, the thrust reverser system used 28-volt power for reverser control and engine bleed air to deploy the translating structure. The electrical system in the thrust reverser incorporated an automatically initiated "stow" command if the pneumatic latches became unlocked in flight. 

 A rocker switch in the cockpit could be positioned to either "NORM" (normal) or "EMER STOW" (emergency). Three indicator lights in the cockpit for each thrust reverser provided the flight crew with thrust reverser status and position information. These lights, "UNLOCK," "DEPLOY" and "BLEED VALVE," illuminated and extinguished during the application and stowing of the thrust reversers. The "UNLOCK" light would remain illuminated any time that a thrust reverser pneumatic latch disengaged or was not in the locked configuration after a thrust reverser was stowed, or if a thrust reverser failed to stow completely.

The AFM Aeronca TR Supplement stated "an inadvertent thrust reverser deployment during takeoff will be indicated by illumination of the affected thrust reverser UNLOCK and/or DEPLOY lights." If this occurred below V1 speed, an aborted takeoff should be performed. If this occurred above V1 speed, the flight crew should maintain directional control, reduce the affected engine thrust lever to idle, place the NORM-EMER STOW switch to EMER STOW and continue the takeoff. 

The procedures stated that, "If UNLOCK or DEPLOY lights do not go out, Thrust Lever [affected engine] - CUTOFF." The procedures stated that the ENGINE SHUTDOWN IN FLIGHT procedure in the basic AFM should be performed. 

The AFM Supplement also contained "Abnormal Procedures" for an inadvertent thrust reverser deployment in flight. Those procedures also specify that, if the UNLOCK or DEPLOY lights do not go out, the ENGINE SHUTDOWN IN FLIGHT procedure should be performed, followed by the SINGLE-ENGINE LANDING procedure from the basic AFM. 

Safety Board investigators reviewed airplane manufacturer's records and the NTSB accident and incident database and found no previously documented instance of an un-commanded inflight deployment of a thrust reverser on a Learjet 35. 

Bottom Line The airplane required two fully qualified flight crewmembers; however, the copilot was not qualified to act as second-in-command on the airplane, and he provided no meaningful assistance to the pilot in handling the emergency.

Further, although the captain's records indicated considerable experience in similar model airplanes, his performance during the flight was highly deficient. Based on the CVR transcript, the pilot did not adhere to industry best practices involving the execution of checklists during normal operations, was unprepared to identify and handle the emergency, did not refer to the appropriate procedures checklists to properly configure and control the airplane once a problem was detected, and did not direct the copilot to the appropriate checklists.

In short, this was a totally unprofessional operation masked as something well run with well-qualified personnel. And four people and an aircraft were lost as a result of that dangerous illusion. 

 This article appears in the May 2016 issue of Business & Commercial Aviation with the title "Total Failure."