higher than the target approach speed (157 knots).
The flare was begun properly; the airplane was about 37 feet above the runway when the captain began increasing the nose-up pitch attitude about
2.5 degrees.
The report described what happened next as a “classic pilot-induced oscillation.” instead of main-taining a constant pitch attitude, as recommended by the MD-11 flight manual, the captain rapidly applied nose-down pitch control. Both pilots felt the airplane’s sink rate increase.
The report said that with one second remaining
before touchdown, the captain had three options:
accept the sink rate and the resulting hard landing; attempt to salvage the landing by increasing thrust and nose-up pitch; or conduct a go-around.
The report said that a go-around would have prevented the accident; the captain chose to try to salvage the landing. He applied nose-up pitch control and increased power from near-flight-idle
thrust to near-takeoff thrust. The sink rate had
just begun to decrease when the airplane touched down on the runway. The report said that the cap-tain moved the control column full forward in an attempt to keep the airplane on the runway, but the airplane bounced back into the air, reaching a
maximum height of five feet.
The airplane was airborne about two seconds. The captain pulled the control column back in
an effort to soften the impact; he also applied left
rudder and right aileron (the report said that in-
vestigators could not determine why he did this). Vertical speed was approximately 13.5 feet per
second when the right-main landing gear struck the runway.
“The energy transmitted into the right-main landing gear during the second touchdown was
3.2 times greater than the Md-11’s maximum cer-tificated landing energy and was sufficient to fully
compress (‘bottom’) the right-main landing-gear
strut and cause structural failure of the right-wing
rear spar,” the report said.
The right wing separated, a fuel-fed fire ignited, and the airplane slowly rolled right. The airplane slid on
the runway and came to a stop inverted 5,126 feet (1,563 meters) from the runway threshold.
The five occupants — the captain, first officer, two
passengers (airline employees) and a jump-seat passenger (a pilot for another airline) — received minor injuries. The airplane — valued at uS$112
million — and the cargo were destroyed by the impact and postaccident fire.
The report said that the probable causes of the accident were “the captain’s overcontrol of the air-
plane during the landing and his failure to execute a go-around from a destabilized flare.”
An approach can become unstabilized if the pilot flying applies stabilizer trim during the flare.
Boeing said that the pilot can lose the “feel” of
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本文链接地址：Stabilized Approach And Flare Are Keys to Avoiding Hard Land(16)
