The National Transportation Safety Board released preliminary data yesterday that suggest the Bethesda man whose small plane crashed into a Newark neighborhood had become confused about the plane's orientation before the aircraft gained altitude briefly, then plummeted rapidly to the ground.
Itzhak O. Jacoby, the plane's pilot, his wife, Gail Jacoby, and their teenage daughter, Atira Jacoby, died in the Nov. 26 crash, which also destroyed cars and buildings and injured 22 people.
The NTSB's brief preliminary report says Jacoby's Beechcraft S35 took off about 10:49 a.m. from Linden Airport in New Jersey and struck a building at 10:53 a.m.
Departing under low-visibility conditions that made it necessary to fly on instruments, the four-seater was given a heading by New York air traffic controllers and told to climb to 5,000 feet, according to the report. A few seconds later, the instructions were revised to 2,000 feet. Then, 35 seconds after that, the controller told the pilot to turn left and revised the heading. There was no reply.
When the controller repeated the new heading, the pilot responded that he had a problem: "I have a gyro problem, maybe some water got into it." Gyroscopes give pilots information that helps them maintain level flight.
During the next minute and 22 seconds, the pilot said twice that he had a problem, but he did not say what it was, the report said. The plane struck a building about two minutes after the pilot first spoke of trouble.
Radar data of the final minutes show that the plane was at 1,100 feet, heading east, when the pilot first reported the problem. The Beechcraft then appeared to veer from "east, to north, to northeast, to northwest, and then back to north," the report said.
During the last 20 seconds before impact, the plane climbed from 2,100 to 2,700 feet and then went into a 7,800 foot-per-minute descent, the report said, crashing into a three-story brick building and leaving a 600-foot-long path of debris.
There are two types of gyros on aircraft--a directional gyro, which is basically a compass, and a "horizontal situation indicator" that tells a pilot whether the plane is climbing, descending or turning. They are kept turning at a constant speed by vacuum pumps.
If a vacuum pump goes bad, the gyros--identical in principle to a child's gyroscope--will gradually slow down and begin wobbling. This makes a confusing mishmash of the pilot's most important instruments.
A pilot in a no-visibility situation would be wholly dependent on these gyros. No pilot, no matter how experienced, can avoid a growing disorientation in which up and down can become confused.
The safety board data indicates a classic situation in which the pilot becomes disoriented and begins climbing into a stall or turns over--or both--and dives at high speed toward the ground.
"Initial examination of both the engine and airframe reveal no pre-impact failure or malfunctions," according to the report.
Investigators are examining the plane's three gyroscopes and a vacuum pump, the report noted. The NTSB's full investigation is expected to take months to complete.
Staff writer Don Phillips contributed to this report.
CAPTION: Personnel from the National Transportation Safety Board pick through debris from a plane crash in Newark Nov. 26 that killed a Bethesda family.