Rare loss of tail fin led to history's worst one-plane crash

By RICHARD PYLE The Associated Press 11/14/01 6:35 PM

NEW YORK (AP) -- Seeking answers to the crash of American Airlines Flight 587, investigators concede they are stumped as to why the Airbus A300's tail fin and rudder broke off in flight.

They can turn to one precedent in commercial aviation history.

On Aug. 12, 1985, a jumbo jet lost its vertical tail section on a flight from Tokyo to Osaka, Japan. The Boeing 747 flew in circles for half an hour before crashing into a 7,000-foot mountain, its pilots still trying desperately to understand why they had lost control.

The crash of Japan Airlines Flight 123 killed 520 people with four survivors, still the worst single-aircraft mishap in commercial aviation.

According to Scott Haskin, an aircraft maintenance specialist and industry historian, the only other recorded cases of tail fin losses involved an Air Force B-52 bomber, a Boeing E8 and a Convair 880 jetliner, all during test flights decades ago.

The American Airlines plane lost its vertical stabilizer and rudder shortly after it took off from John F. Kennedy International Airport and turned left over Jamaica Bay, in Queens, on a flight to the Dominican Republic.

Without this two-part tail assembly, the jetliner would have suffered a loss of stability and turning control. Investigators said witnesses described a "wobble" and the cockpit voice recorder revealed "suggestions of a loss of control" 17 seconds before the plane plunged into a residential neighborhood in the Rockaways, killing all 260 people aboard and five on the ground.

Within 48 hours, the 27-foot tail fin with the AA logo and the rudder formerly attached to it had been fished out of Jamaica Bay and taken to a nearby airport for study. Investigators said Wednesday that the tail fin showed no sign of damage from external impact; the rudder was in pieces.

Most forces exerted on an aircraft are from front to rear. The tail fin is made of aluminum or composite material and is designed to flex from side to side, but whether it could be snapped off by a lateral force was unclear. [OG note--saw one of the TV experts, he said this tail was made from graphite.]

National Transportation Safety Board experts said they did not know why the tail section was sheared cleanly away from the fuselage as if by a giant knife.

"We'll be looking very carefully at how the tail failed," NTSB investigator George Black Jr. said.

They would not speculate on whether the tail separation was possibly connected with "air frame rattling" noises heard on the voice recorder or with "wake turbulence" from a Tokyo-bound Japan Airlines 747 that had taken off a minute and 45 seconds ahead of Flight 587.

Wake turbulence is a common, if unseen, menace that can cause a following plane to veer out of control in seemingly calm air, and it has been blamed for some past mishaps.

Walter Sheriff, a retired American Airlines captain who studies the phenomenon, said the wake turbulence from the four-engine JAL 747 could have struck the A300 with "tornado-like lateral force."

In the 1985 Japan Airlines crash, the aircraft suffered "massive decompression" -- a sudden loss of cabin pressure -- when the dome-shaped pressure seal in the rear of the passenger compartment unexpectedly collapsed.

While no one was sucked out, the explosive force destroyed hydraulic lines that converged in the tail and ripped away the vertical stabilizer and rudder.

Having no rear view mirror, the cockpit crew did not know it had lost the tail, only that the aircraft's control surfaces -- flaps, elevators and rudder -- were suddenly and mysteriously inoperative.

Capt. Masami Takahama declared an emergency, telling air controllers a rear door had broken. Takahama was able to steer by applying and easing power to the engines, but with no rudder to brake the turns, the jetliner turned in uncontrolled circles, unable to reach Tokyo's Haneda airport or the nearby U.S. Air Force base at Yokota.

While passengers in the windy cabin scribbled last notes to loved ones, some people on the ground snapped photos of the crippled jumbo jet, clearly showing its tail fin was missing. But this information was not passed on to aviation authorities before the crash.

Investigation eventually showed that the rear pressure dome, damaged earlier in a hard landing, had been improperly repaired and eventually gave way. Boeing, which built the 747 and had supervised the pressure dome repairs, took responsibility for the failure. JAL's president later resigned.

-- Anonymous, November 14, 2001