ERA16LA225 · Piper PA 28-236

The private pilot stated that, during the landing roll, the airplane suddenly departed the left side of the 150-ft-wide runway into the grass, resulting in substantial damage to the left wing. The pilot initially thought a tire had blown, but when he exited the airplane, he noticed a McDonnell-Douglas MD-83 parked on the movement area of the adjacent taxiway performing a maintenance test run of its engines and realized he had been blown off the runway.

Before the accident, the tower controller had cleared the MD-83 to position itself in the movement area adjacent to the landing runway; the positioning resulted in the engine and resultant exhaust being directed toward the landing area of the runway. The controllers did not warn the accident pilot about the MD-83 and its purpose on the taxiway, as required per FAA policy. Additionally, the local procedures for positioning transport category airplanes to do engine test runs was not formally documented, and the informal procedure in use at the time of the accident did not adequately protect aircraft operating on the airport from jet blast. The estimated idle jet engine exhaust velocity of the MD-83 was 35 knots. Combined with the prevailing wind, the estimated sudden right quartering headwind acting on the accident airplane would have been about 39 knots. As a result of this investigation, the air traffic control tower and airport authority developed and disseminated procedures for conducting high-power engine test runs in the movement area of the airport.

Verbatim NTSB analysis and probable cause from the NTSB dataset