Wednesday, 8th of March, 2017
– United States of America
On March 8, 2017, about 1452 eastern standard time, Ameristar Air Cargo, Inc., dba Ameristar Charters, flight 9363, a Boeing MD-83 airplane, N786TW, overran the departure end of runway 23L at Willow Run Airport, Ypsilanti, Michigan, after the captain executed a rejected takeoff. The 110 passengers and 6 flight crewmembers (two airline transport pilots and four flight attendants) evacuated the airplane via emergency escape slides. One passenger received a minor injury, and the airplane sustained substantial damage. The airplane was operated under the provisions of Title 14 Code of Federal Regulations Part 121 as an on-demand charter flight and was destined for Washington Dulles International Airport, Dulles, Virginia. Visual flight rules conditions prevailed at YIP at the time of the accident.
The flight crew prepared for take-off and calculated V-speeds (V1, VR, V2) using “Normal Thrust Takeoff”, a 10 kts headwind, and a take-off weight of 146,600 lbs. The V-speeds for this configuration were 139 kts, 142 kts, and 150 kts, respectively. However, the flight crew chose to increase VR to 150 kts to allow for more control during take-off in the presence of windshear.
During takeoff roll, at 14:51:56 (about 3,000 ft down the runway) and about 138 kts of airspeed, the control column was pulled back slightly from a non-dimensional value of -7 to -5.52. The airplane�s left elevator followed the control input and moved from a position of -15° trailing edge down to -13° trailing edge down. The right elevator did not change and stayed at approximately -16° trailing edge down. At 14:52:01 a large control column input was made (151 kts and 4100 ft down the runway) to a non-dimensional 18.5 and the left elevator moves to a position near 15° trailing edge up. After 14:52:05 the right elevator moves to -13° trailing edge down, but no more. The airplane does not respond in pitch and does not rotate. The captain decided to abort the takeoff.
The maximum groundspeed was 163 kts (173 kts airspeed) and the airplane began to decelerate as soon as the brakes were applied at 14:52:08. Spoilers were deployed at 14:52:10 and thrust reversers were deployed between 14:52:13 and 14:52:15. The aircraft could not be stopped on the runway. The airplanes ground speed was 100 kts when it left the paved surface.
The aircraft overran the end of the runway, damaged approach lights, went through the perimeter fence and crossed Tyler Road.
It came to rest on grassy terrain, 345 meters past the end of the runway, with the rear fuselage across a ditch. The nose landing gear had collapsed. Runway 23L is a 7543 ft long runway.
Post-accident examination by the NTSB revealed movement of the control column in the cockpit appeared normal; the control columns were free to move, and the elevator control tabs moved as commanded. However, when investigators tried to move the elevator surfaces by hand, the left elevator moved normally, but the right elevator was jammed in a trailing edge-down position (airplane nose down). Upon further inspection, the right elevator geared tab inboard pushrod linkage was found damaged which restricted movement of the right elevator surface but allowed movement of the control tab. After the damaged components were removed, the elevator could be moved by hand.
Examination of the flight data recorder data indicates that during the taxi and take-off roll, the left elevator moved normally, but the right elevator did not move. During takeoff roll, the left elevator began a large airplane nose-up movement (consistent with rotation) at an airspeed of about 152 knots and continued for five seconds to about 166 knots. There was no change in the airplane pitch attitude during this time. The airplane data then are consistent with the takeoff being rejected. The maximum recorded airspeed was about 173 knots.
Review of previous flight data showed normal movement of both the left and right elevator surfaces. The airplane flew to Ypsilanti two days before the accident.
– Probable Cause: “The NTSB determines that the probable cause of this accident was the jammed condition of the airplane’s right elevator, which resulted from exposure to localized, dynamic wind while the airplane was parked and rendered the airplane unable to rotate during takeoff. Contributing to the accident were (1) the effect of a large structure on the gusting surface wind at the airplane’s parked location, which led to turbulent gust loads on the right elevator sufficient to jam it, even though the horizontal surface wind speed was below the certification design limit and maintenance inspection criteria for the airplane, and (2) the lack of a means to enable the flight crew to detect a jammed elevator during preflight checks for the Boeing MD-83 airplane. Contributing to the survivability of the accident was the captain’s timely and appropriate decision to reject the takeoff, the check airman’s disciplined adherence to standard operating procedures after the captain called for the rejected takeoff, and the dimensionally compliant runway safety area where the overrun occurred.”