Saab 2000

Probable Cause

The landing gear manufacturer’s incorrect wiring of the wheel speed transducer harnesses on the left main landing gear during overhaul. The incorrect wiring caused the antiskid system not to function as intended, resulting in the failure of the left outboard tire and a significant loss of the airplane’s braking ability, which led to the runway overrun. Contributing to the accident were (1) Saab’s design of the wheel speed transducer wire harnesses, which did not consider and protect against human error during maintenance; (2) the Federal Aviation Administration’s lack of consideration of the runway safety area dimensions at Unalaska Airport during the authorization process that allowed the Saab 2000 to operate at the airport; and (3) the flight crewmembers’ inappropriate decision, due to their plan continuation bias, to land on a runway with a reported tailwind that exceeded the airplane manufacturer’s limit. The safety margin was further reduced because of PenAir’s failure to correctly apply its company-designated pilot-in-command airport qualification policy, which allowed the accident captain to operate at one of the most challenging airports in PenAir’s route system with limited experience at the airport and in the Saab 2000 airplane.