July 19, 1999
WASHINGTON (AP) _ The departure was later than expected and the skies hazier
than desired, but by all accounts John F. Kennedy Jr.'s flight Friday night was
normal until about 17 miles from the airport in Martha's Vineyard, Mass.
Within 30 seconds, the plane lost 700 feet in altitude _ a relatively large
amount _ and slipped below radar coverage. The Coast Guard believes it crashed
off the island's coast.
While the government's investigation has just begun, flight instructors have
several theories about what may have happened.
One possibility is engine failure, another structural breakdown. A third is
simply running out of gas. But the most likely explanation is pilot error
caused by two things: disorientation in the night sky and a lack of experience
in a swift new plane.
"This wouldn't be the first time a pilot has lost control of a plane because
of spatial disorientation or vertigo," said Larry Gross, an aviation professor
at Purdue University in West Lafayette, Ind. He also is a certified flight
instructor with over 12,000 flight hours.
Pilots can become disoriented because their inner ear tricks them into
thinking they are level when in fact they are turning. At night or in cloudy
skies, there are few visual landmarks to reorient the brain. If a pilot is not
trained to use flight instruments, as Kennedy wasn't, he can begin a dive _
even a steep one _ without realizing it.
"Literally, you lose control of the plane and you can't determine if you're
climbing or descending, turning or flying level," Gross said.
Vas Patterson, a flight instructor at the ATC Flight Training Center in Fort
Washington, Md., just south of Washington, said such disorientation may have
put Kennedy "behind" his relatively fast Piper Saratoga.
The Saratoga, which Kennedy registered on April 30, had a top speed of
around 200 mph. Kennedy's first plane, a Cessna 182, had a top speed of closer
to 150 mph.
"The airplane he was flying was a high-performance, complex airplane," said
Patterson, who has logged 900 flight hours. "It was a step up from what he was
used to."
Friends say Kennedy, his wife, Carolyn Bessette Kennedy, and her sister
Lauren Bessette had intended to start their trip early Friday evening. Instead,
they were delayed because of traffic in New York and Lauren Bessette's work
commitments.
The National Transportation Safety Board said the plane took off from the
Essex County Airport in Fairfield, N.J., at 8:38 p.m. The flight path took the
plane through hazy skies along the southern coast of Connecticut at 5,600 feet.
At 9:26 p.m., Kennedy was off Westerly, R.I., and began to head over the
water directly to Martha's Vineyard. There was a gap in the first radar tapes
reviewed by investigators, but Kennedy's plane was again detected at 9:40 p.m.
about 17 to 18 miles west of the airport, flying at about 2,500 feet.
During the next 30 seconds, the plane dropped to 1,800 feet, where it left
the radar scope. The 700-foot drop would have equated to a 1,400
foot-per-minute descent rate, far faster than the normal rate of 300 to 500
feet-per-minute.
One explanation for the drop, Gross and Patterson said, may have been that
the engine stopped. Another might be structural failure, such as losing a wing
or the plane's tail. Yet another cause may have been "fuel starvation," or
running the gas tanks dry.
Yet both instructors conceded that an aircraft breakup would probably have
triggered a more rapid descent. A stalled engine, by contrast, would not have
prevented the plane from gliding more gently.
Instead, they view the inky skies, the dark ocean, the mid-summer haze and
the lack of landmarks as a deadly combination. They believe it may have sent
Kennedy unknowingly into a descent from which he could not recover.
"In the mind of most pilots, the best conjecture is that the pilot lost
control of the plane," Gross said. "But we'd hate to say that for sure and then
find that there was some structural failure of the plane."
