20th of September 2019, Downdraft, Blog #721

After an uneventful climb to an altitude of 10.500 feet, 10 skydivers exited a Cessna 208B Grand Caravan. After the skydivers left the aircraft the pilot returned to their airport of departure, Pepperell Airport (Massachusetts, USA).

Fire-fighters at the scene shortly after the accident (Source: kathrynsreport.com © Unknown)

The weather was good, with clear skies and no reported wind. The return flight to Pepperell was uneventful and the aircraft made a normal approach to runway 24 (a 2820 ft long an 25 ft wide grass runway) with a final approach speed of 60-65 KIAS. At an altitude of approximately 15-20 feet the flight controls became ineffective, and power was added by the pilot but the pilot was unable to arrest the descent, resulting in a hard landing. The aircraft touched down on the right-hand main landing gear and the nose landing gear, then bounced back into the air. 95 feet later, a second touchdown occurred, which caused the nose landing gear to fail (breaking free of the aircraft) and the aircraft to slide to the right-hand side of the grass runway, crossed the asphalt parallel runway before the right-hand wing collided with a small tree. This caused the aircraft to spin around. The left wing then contacted the ground and bent the last three ft of the wing tip up before coming to a stop approximately 370 feet from the initial touchdown.

Aerial overview of the accident scene, not the tyre marks in the grass of the left wingtip (Source: kathrynsreport.com © Unknown)

The National Transportation Safety Board was informed about the accident and had the aircraft inspected by an FAA Inspector. The pilot was interviewed by telephone; the NTSB did not travel to the scene of this accident.

Based on the information provided by the FAA Inspector and the interview with the pilot, the NTSB concluded that the probable cause of the accident was; "The pilot's loss of control when the airplane encountered a downdraft during landing approach, which resulted in a subsequent hard landing and gear collapse."

This blog was written using information from the NTSB Aviation Investigation Final Report (accessible by clicking on the .pdf file below) and the NTSB Investigation Docket (https://data.ntsb.gov/Docket?ProjectID=100315)

Report_ERA19TA278_100315_9_21_2025 3_09_50 PM.pdf

Download PDF • 800KB

The aircraft, after recovery, note the damaged propeller and bent left wing (Source & © NTSB)

Sources on the internet, and familiar with the airport, state that the end of runway 24 has a history of (erratic and unpredictable) windshear. Strong thermal rotors and very high abrupt tree line contribute to strong circular rotors and very unpredictable shear.