Piper PA44 N553MD accident near Houlton, Maine

Probable cause

The pilot's descent below the published minimum descent altitude in night instrument meteorological conditions without visual contact with the runway environment, which resulted in a collision with trees and terrain short of the runway. Contributing to the accident were the pilot's acute fatigue and his decision to attempt an instrument approach procedure that was not authorized at night.

NTSB analysis

The airline transport pilot was ferrying the airplane across the Atlantic Ocean. The accident occurred as the pilot was completing the third leg of the trip and was conducting an instrument approach in dark night instrument meteorological conditions. Radar data indicated that the pilot conducted the entire approach at altitudes 300 ft to 700 ft lower than the instrument approach procedure authorized. Track data recovered from an onboard GPS unit depicted the airplane making "S" turns back and forth across the final approach course and ended to the right of the extended runway centerline in the vicinity of the accident site. The airplane collided with trees and terrain about 2.5 nautical miles short of the runway. The wreckage distribution was consistent with controlled flight into the terrain, and postaccident examination revealed no evidence of any preexisting mechanical anomalies that would have precluded normal operation of the airplane. The reported 300-ft ceiling at the time of the accident was well below the approach's published 700-ft ceiling minimum for planning purposes, and the approach was not authorized at night. It is likely that the pilot continued to descend below the published minimum descent altitude without establishing visual contact with the runway environment rather than conducting a missed approach.

The trip originated 21.6 hours before the accident occurred and included 16.6 hours of flight time and a 3.8-hour ground delay that may have allowed time for the pilot to sleep. Even if the pilot napped during the ground delay, it is unlikely that the sleep would have been fully restorative. Additionally, assuming the time required to wake, travel to the airport, and complete preflight inspections and planning before beginning the trip's first leg, the pilot's duty day could easily have reached or exceeded 24 hours. The total amount of flight time relative to the time available for rest strongly suggests that, during the instrument approach, the pilot was likely experiencing the effects of acute fatigue, which degraded his performance, including his handling of the airplane and his decision-making.

Text from the NTSB. Open the NTSB docket for ERA15FA326 for the full record.