Runway Excursion During Training Demonstration

Casualties unknown • Saint Louis, MO, US

A flight crew demonstration of a reversing technique during training resulted in a runway excursion involving a left wing and reverser bucket strike.

What happened

During an initial training session for a first officer, the captain attempted to demonstrate what was described as a more efficient reversing technique using a touch-and-go maneuver. During the maneuver, the aircraft departed the left side of the runway at the 4,000-foot marker. The aircraft dragged its left wing and the lower left reverser bucket along the ground, continuing for an additional 2,000 feet before coming to a complete stop. There were no injuries reported.

The investigation

The investigation examined the configuration of the aircraft at the time of the excursion. Evidence showed that the flaps were in full deployment and that neither thrust reverser had been stowed. Data from the Digital Flight Data Recorder (DFDR) indicated a constant decay in airspeed from the moment of initial touchdown until the aircraft stopped, with no indication that the airplane had completely lifted off the ground following the initial landing.

Physical evidence showed no contact between the nose wheel and the runway at the moment directional control was lost. At the time of the accident, there was a right crosswind. The investigation also noted that according to McDonnell Douglas Letter #4, reverser buckets will not stow if the Engine Pressure Ratio (EPR) is above approximately 1.2.

Probable cause

The loss of directional control was caused by the use of reverse thrust, which significantly reduces rudder effectiveness, compounded by a right crosswind and the failure to stow the thrust reversers.

Frequently asked questions

What happened in the 1993-03-12 Mcdonnell Douglas DC-9-31 accident near Saint Louis, MO?

A flight crew demonstration of a reversing technique during training resulted in a runway excursion involving a left wing and reverser bucket strike.

What aircraft was involved and where did it happen?

The accident on 1993-03-12 involved a Mcdonnell Douglas DC-9-31, registration N978Z, operated by Trans World Airlines, Inc., at Saint Louis, MO.

What was the probable cause of the accident?

The loss of directional control was caused by the use of reverse thrust, which significantly reduces rudder effectiveness, compounded by a right crosswind and the failure to stow the thrust reversers.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X11935. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.

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