WASHINGTON -- Though 31 Black Hawk troop assault helicopters have been involved in major accidents that killed 65 people over the past six years, the Army maintains it is the safest helicopter it has ever flown.
The UH-60 Black Hawk 'has the lowest accident rate of any Army helicopter in the first six years of its use,' Pentagon spokesman Maj. Phil Soucy said Wednesday. Helicopter safety records improve with experience, he said.
The accident and death total includes the two helicopters that collided Tuesday night at Fort Campbell, Ky., killing all 17 soldiers aboard.
Soucy said there is 'no evidence right now to support grounding of the fleet' as a result of the crash. An Army official who spoke on the condition of anonymity said there was 'evidence accumulating' that the tragedy may have been caused by human error.
Soucy said only one of the prior 'Class A' accidents involving a death, serious injury, or damage of more than $500,000 had been caused by a technical flaw that required design changes.
The $20 million redesign of a stronger rotor blade spindle followed a spindle failure that caused an April 18, 1985, crash at Fort Rucker, Ala., killing three soldiers, Soucy said.
A month earlier, 12 men were killed in a Black Hawk crash at Fort Bragg, N.C., when the absence of a bolt caused the flight controls to jam, but it was not considered a technical flaw in the aircraft.
Soucy acknowledged that the cause of a March 11, 1986, crash, which also killed three soldiers near Fort Rucker, has never been found.
But a grounding of all Black Hawks was lifted a month later after changes were made in the operations manual to intensify maintenance and pre-flight inspection.
The latest of several groundings was ordered in May 1987 when a failed oil cooler in a tail rotor drive shaft forced a pilot to land in West Germany.
Army records show that 'about 80 percent of Black Hawk crashes are caused by human error,' Soucy said. Three-fourths of the human errors were found to have been originated within the helicopter crews themselves, he said.
Bad weather was the next highest factor causing Black Hawk crashes, the spokesman said. 'Material failures are only a small percentage,' he said.
A published report last year said the Black Hawk's electrical controls had responded incorrectly to strong radio and other electronic signals in the atmosphere, ca electromagnetic interference or EMI.
The Army 'has looked at EMI intensively ... and found it not to be a safety hazard,' Soucy said. Black Hawk pilots have been cautioned that if they fly near a powerful radio or television transmitter such things as instrument panel warning lights may be turned on.
Army tests have shown the worst thing that might happen from EMI is that the helicopter's rear 'stabilator' rotor might swing four or five degrees, Soucy said. He termed this a 'minor movement ... easily corrected by a reasonably trained crew.'
Soucy called the EMI threat 'things that scare you in the night that turn out to be only clothes left on the chair when you turn on the light.'
Tuesday's crash was not the Army's worst peacetime helicopter accident, Soucy said; 44 were killed in a 1982 Chinook helicopter crash in West Germany.
Manufacturer Sikorsky Aircraft, a Stratford, Conn., division of United Technologies Corp., has delivered 846 Black Hawks to the Army as well as another 44 to the Air Force and the Drug Enforcement Administration.
Each 10-ton Black Hawk costing about $6 million can carry 11 fully-equipped soldiers in addition to its normal three-man crew to a target 370 miles away and return, Soucy said.
The helicopter began operational flights with Army units in 1982, although earlier test models had been delivered as early as 1979, he said.
