L.A. Links Helicopter Crash to Defective Part From Manufacturer : Aircraft: Confidential report says maintenance crews believed maker had taken care of malfunction. Two police officers and a bystander were killed.
A Los Angeles police helicopter crashed in June because the manufacturer “sold us (an) engine . . . which contained a defective part,” the city’s Department of General Services, which was responsible for maintaining the aircraft, says in a confidential report.
The July 24 report on the crash that killed two police officers and a bystander follows an earlier claim from the manufacturer that someone had failed to comply with an emergency bulletin calling for repair or replacement of the crucial part.
Overall investigation of the crash is being handled by the Police Department, which has yet to comment officially or issue any reports on its findings. Police officials, however, have been quoted as saying that a malfunction of the part--called a “freewheeling unit"--led to the accident.
City Atty. James K. Hahn, while conceding that there are problems with the maintenance policies, procedures and record-keeping of the Department of General Services, said Friday that these “had nothing to do” with the June 13 crash of the French-built Aerospatiale 350 B1 helicopter.
“In this regard, the city is pursuing litigation against all responsible parties,” Hahn said in a prepared statement, without indicating who those parties might be.
Citing the pending litigation, the Department of General Service refused to comment on the report.
The Aerospatiale Helicopter Co., which built the aircraft, and the Turbomeca Engine Corp., which manufactured the engine, have consistently declined to discuss the incident. Both firms have U.S. headquarters in Grand Prairie, Tex.
The freewheel unit is part of the drive train that ties the helicopter’s engine to the main rotor, which provides lift.
The freewheel clutch allows the rotor to spin freely in the event of engine failure, permitting the pilot to make a safe, soft landing through a maneuver known as “auto-rotation.” Pilots say that if the freewheel unit is not working properly, the maneuver is difficult to execute.
While many questions remain about the June 13 accident, it is known that the crew radioed a report of engine failure seconds before the craft crashed into a parking lot in Southwest Los Angeles.
In his confidential July 24 report to Mayor Tom Bradley, Randall C. Bacon, general manager of the Department of General Services, said he had reached four conclusions as the result of an internal staff investigation and an independent audit of the city’s helicopter maintenance records by Geis-Alvarado and Associates:
* “A defective freewheeling clutch assembly was the cause of the engine problem that caused the police helicopter to crash . . .
* “Turbomeca Engine Corp. of Grand Prairie, Tex., sold us Engine Number S/N7083, which contained a defective part (the freewheeling clutch). The engine was sold to us with a certification that the engine was ‘airworthy’ as of July 31, 1990.
* “Our maintenance staff followed the industry-accepted practice of considering that all repairs and corrections to the engine had been made as of the date it was certified as being airworthy. . . .
* “Our maintenance staff is still using sloppy and inadequate methods of maintaining helicopter maintenance records, even though there have been two audits within the last two years identifying the problem. However, it should be noted that there is no indication that these practices have been the cause of any helicopter accidents or incidents.”
According to Bacon’s report, the engine from the police helicopter was shipped to Turbomeca for unrelated repairs in July, 1989.
Documents compiled by helicopter industry representatives show that in April, 1990, Aerospatiale and Turbomeca issued a bulletin warning that because of “slippage” in some freewheel units, operators of helicopters equipped with them should “modify the freewheel shaft assemblies . . . as soon as possible, or on Oct. 31, 1990, at the latest.”
Bacon said that four months after that, while the engine was still “under Turbomeca control,” a good freewheel shaft assembly was replaced with a defective one.
City maintenance personnel assumed the necessary modifications had been made in accordance with the bulletin, Bacon said.
A month after the crash, an Aerospatiale/Turbomeca telex was sent to all authorized repair facilities, commenting on the accident.
“Without prejudicing the conclusions of the inquiry, it was noted that the free wheel on the helicopter . . . was not compliant with the directives of Turbomeca,” the telex said. Eighteen months before the crash, Geis-Alvarado had inspected the city’s maintenance operation. The independent auditing firm concluded that while the overall work was “excellent,” there were “many minor maintenance errors.”
Craig E. Geis, president of the firm, wrote at the time that “while none of these errors have resulted in a mishap, it is my opinion, and that of the pilots, that if the present trend continues, an accident will occur.”