Pilot Chowdry and airplane fingered in fatal L-39 crash
The NTSB’s recently released factual report of the crash on January 24 last year of a privately owned Aero Vodochody L-39 former Czech Republic military jet trainer that killed Wall Street Journal aerospace editor Jeff Cole riding as a passenger and pilot Michael Chowdry, founder and CEO of cargo carrier Atlas Air, draws attention to the pilot’s skill, experience and attitude, as well as a possible severe and sudden change in the airplane’s handling characteristics when it lost the aft canopy during takeoff from Colorado’s Front Range Airport.
Chowdry became one of the first customers to own and fly a Boeing Business Jet, and he worked with Boeing to publicize the BBJ. Chowdry received an ATP certificate in August 1999 and he was a CFI. He also had a type rating in the BBJ. On his last FAA physical in July 2000, he reported that he had 5,100 hr of flight experience, with 250 hr during the last six months. On his last insurance policy, Chowdry stated he had completed a biennial flight review and instrument competency check in August 2000. But the sum of his flying experience is not clear because he reportedly never kept a logbook. In addition, former BBJ pilots who flew with Chowdry do not paint a flattering picture of him as an aviator.
Chowdry reported in that August 2000 insurance application that he had 150 hr in the L-39, but his flight instructor estimated he had between 40 and 50 hr, and maintenance logs suggested that Chowdry had 38.6 hr of L-39 experience, 6.6 of which were in the 18 months preceding the accident.
Chowdry made his first flight in the airplane in October 1997, then purchased it and registered it as N602MC in December. In March and April 1998, he received 13 hr of ground school and 11 hr of flight training in the airplane. On April 17, 1998, the FAA issued a letter of authorization (LOA) to Chowdry that was valid through April 30, 2000. The LOA required him to make at least three takeoffs and landings in the L-39 within the preceding six calendar months, or the LOA would be rescinded. In July 2000 he received an estimated two hours of ground instruction and two flights in the airplane with an instructor for a total of 2.3 hr. The FAA issued Chowdry a new LOA that was good through the end of last month.
The NTSB investigation will consider the possibility of pilot fatigue as a factor in the accident. According to the Safety Board, an employee of Chowdry said he flew to Washington in his BBJ for the Presidential inauguration and associated events on January 20 last year. On January 21 and 22 he flew (with three other crewmembers) to Europe and on to Shanghai, China, with stops at several locations for business meetings. On January 23 he was in Seattle, Wash. for a five-hour meeting, and then flew home to Denver that evening.
At about 11:26 the next morning he took off in the L-39 and crashed less than a minute later. Witnesses reported the airplane never reached more than 300 or 400 ft agl, appeared slow for a jet, was oscillating and, just before the crash, made a medium to steep left bank before straightening out. The FAA estimated the speed of the airplane was 200 kt when it crashed.
Was C.G. Change a Contributing Factor?
Witness statements and maintenance records indicate that Chowdry had nearly all of his L-39 flight experience with his airplane’s empty weight c.g. between 34 and 35 percent MAC. In October 1999, during its annual inspection, about 200 lb of weight was placed in the airplane to produce an empty weight c.g. of 27.6 percent MAC. Maintenance records and a flight-tracking sheet suggest that the pilot had 6.1 hr of flight experience with the airplane at this c.g. moment.
In October 2000, during its next annual, the 200 lb of weight was removed from the airplane to create a c.g. of about 34.98 percent MAC. Witness statements and maintenance records indicate that the accident flight takeoff was Chowdry’s first since the c.g. had been adjusted back to the 34- to 35-percent MAC range.
The Safety Board will also try to determine if the c.g. of the airplane shifted considerably aft. An experienced L-39 pilot told the NTSB that the flight controls become “very sensitive” in an aft, out-of-c.g. condition. An L-39 instructor pilot told of an owner who had lost his rear canopy while on climbout, without a passenger in the seat. That owner reported that when he was trimming the nose down, the rear canopy suddenly separated from the airplane. The airplane immediately “nosed up in a dramatic fashion” and that “aggressive nose-down trim and forward stick movements were required to restabilize the airplane.”
Another experienced L-39 pilot said that an aft c.g. would cause the airplane to oscillate. “At a given oscillation amplitude, the airstream will get under the airplane’s nose to produce a violent pitch up.” L-39s are “very pitch sensitive” and the trim works “very fast,” according to this L-39 pilot. L-39s have a “tendency to oscillate” right after takeoff. The airplane is “very easy to over-control, particularly if the pilot is startled,” said another L-39 pilot. “You’ve got to be well trained and current to fly the airplane.”
A pilot witness to the accident said the airplane was “moving up and down very quickly, in a real quick jerky manner.” He said the up and down movements were so fast that there was no apparent altitude change.
History of Canopy Problems
An employee pilot of Chowdry, who had LOAs in MiG fighters, said he flew with Chowdry in the back seat of the L-39 on Nov. 18, 2000, about three months before the crash. He said that while in flight, during high-g maneuvers, he could hear and feel the rear canopy chatter loudly. This abnormality, along with a persistent intermittent canopy ajar light, persuaded him to end the flight after approximately 30 to 35 min in the air. This was the last flight before the accident.
Another L-39 pilot said that on two occasions he has had passengers inadvertently move the blue seal depressurization knob (deactivating the rear canopy seals) while getting into the back seat. He said that for low-altitude flights, the front-seat pilot probably would not be aware of it.
During an L-39 flight in March with Chowdry at the controls, a non-pilot passenger said they flew around the airport at approximately 100 ft “and the airplane seemed to be wallowing around.” After an uneventful landing and taxi to the hangar, the engine was shut down. “When Chowdry opened his canopy, it swung all the way over” and fell to the ground, said the passenger. It was also discovered that one of the engine air intake covers had been left in place and had made its way “some distance inside the engine air intake duct.”
Following the crash, an examination of the damage to the rear canopy and the aircraft’s structure by the Life Science Laboratory in San Antonio led investigators to believe both the front and rear canopy locks were not properly secured. Pieces of the failed acrylic transparency of the aft canopy were also sent to the U.S. Air Force Research Laboratory in Ohio. Its representative stated that the back canopy transparency failed because of acrylic “embrittlement” (chemical contamination to the acrylic substrate). He said this could be a result of “aggressive cleaning fluids getting into the canopy frame and staying there during thermal and structural loading.”
Although the accident airplane was a 1996 model, the canopy design comes from the 1950s, and there are no channels in the canopy frame to allow fluids to dissipate.
Former Atlas Pilots Comment on Chowdry
A former pilot for Chowdry’s BBJ said he never saw him “keep any sort of logbook–a perennial problem with our insurance carrier.” Another former BBJ pilot who worked for Chowdry told NTSB investigators he “didn’t like to follow the rules, had weak situational awareness skills, had aviation-oriented attention deficiencies, panicked easily and had spontaneous incapacitations.” Chowdry had “weak crew communication skills, poor utilization of checklists and weak procedural skills,” according to another former Atlas BBJ pilot. (Atlas sold the BBJ shortly after Chowdry’s death.)
Yet a Cessna 401 pilot who watched the accident L-39 as it pulled up next to the Cessna on the runup pad before its last flight said “it appeared [Chowdry] was following a full-blown checklist.” There were several “high engine” runups over a five- to seven-minute period.
All the pilot witnesses but one said they could not recall hearing any radio transmissions from the jet, in flight or while taxiing. But one pilot witness in a Piper Comanche on final before the jet took off said Chowdry reported on Unicom that he was “departing Runway 26.”
It will be several months before the NTSB sorts out all the discrepancies and details of this tragic accident and issues the probable causes and related factors.