It's a fact of US military life that the combination of high-performance jets and pilots trained to fly hard in combat can prove disastrous. Last month's crash of a Navy F-14A fighter in a Nashville suburb is only the latest example of an all-too-common phenomenon: peacetime aviation accidents.
For the Pentagon, the good news is that its flight safety record may be getting better. A new Government Accounting Office study released in Washington last week judges that the number of major US military plane accidents has fallen sharply over recent decades.
Or has it? The bad news is that some critics say the military's flight safety data are flawed, calling GAO's conclusions into question.
Alan Diehl, a veteran Air Force safety official, alleges that the military fails to disclose all mishaps or conducts improper investigations, thereby laying a foundation for new disasters.
''I do not have any problems with what the GAO did. It was told to look at the military statistics. My problem is that the military statistics are inaccurate,'' says Dr. Diehl, who works at Kirtland Air Force Base in New Mexico.
Diehl has not been alone in leveling such allegations. Similar charges were made in a 1991 letter to former Air Force chief of staff Gen. Merrill McPeak from the service's then-director of aerospace safety, Brig. Gen. Tom Hall.
''I have witnessed command manipulation of mishap cost and classification to improve the command statistics and image, shallow and incomplete investigations into mishap causes, interference by major command staffs with the investigative board process, and punishments of board members for unpopular findings,'' Hall said in his letter. He has since retired.
The GAO report shows a major drop - from 309 to 76 - in the number of Class A mishaps per year between fiscal years 1975 and 1995. Fatalities fell from 285 to 85. Class A mishaps involve loss of life or an aircraft or damage of at least $1 million.
The report is not entirely rosy, though. During the study period, it says, 3,810 people died and 3,483 aircraft were destroyed in Class A mishaps. It also says that between fiscal years 1994 and 1995, human error was a factor in 73 percent of Class A mishaps.
In its most troubling finding, the report questions the integrity of military-crash inquiries. It points out that voting majorities on the five-officer investigative boards come from the very commands whose aircraft are involved in the mishaps being probed.
''This creates, at a minimum, the appearance that investigations are not completely independent,'' says Rep. Ike Skelton (D) of Missouri, who requested the GAO study after a spate of military crashes last year.
Other experts, including some officers, are far more critical of the way flight accidents are investigated. They claim that the armed forces often conceal or misreport serious mishaps. They say the services also manipulate findings to protect officers' careers and their own safety records and images. The GAO declined to delve into these contentions.
''The real question is why are the services allowed to investigate themselves?'' asks Diehl, who is campaigning to reform military crash inquiries. ''Sometimes the units don't accurately report accidents.''
Diehl made similar charges in a complaint he filed with the Pentagon in October 1994. The complaint documented 30 mishaps in which military officials allegedly hid facts, conducted flawed inquiries, or misplaced responsibility. The Defense Department's Inspector General's Office is still investigating the complaint.
A former National Transportation Safety Board official and aviation psychologist, Diehl was the top civilian at the Kirtland-based Air Force Safety Center from 1987 until October 1994. He says he was ''involuntarily reassigned'' to other duties for repeatedly questioning flawed safety procedures.
His complaint and a spate of accidents prompted the Air Force in June to convene an independent safety review commission. The panel, which found evidence of malfeasance in some inquiries, recommended improved safety and mishap investigative procedures.
''The committee found that [the Air Force] had an outstanding safety record, but that things could be improved,'' says Maj. Bob Watson, an Air Force spokesman.
Diehl contends there have been no improvements. Speaking in an interview, he says, the ''Air Force ... has become more sophisticated in hiding Class A mishaps over the last decade. There are accidents that have happened that are not in the data base. If the unreported accidents had been counted, the actual rate would show an increase.''
He cites an Air Force Times article that quoted Lt. Col. Jerry Perkins, former director of data analysis for the Air Force Safety Center, as acknowledging that an accident at Moody Air Force Base in Georgia, in which more than $1 million in equipment on an F-16 was destroyed, was not classified as a Class A mishap.
In a more serious allegation, Diehl says that investigating officers are often threatened with having their careers ruined for refusing to endorse flawed results, to change their findings, or to agree to pre-determined conclusions.