What happened
During the climb phase at approximately 18,000 feet, an Atlantic Southeast Airlines flight experienced a critical mechanical failure when a blade detached from the left propeller. This separation caused significant damage to the left engine nacelle and created intense aerodynamic drag. The aircraft subsequently suffered a loss of lift on the left wing and experienced diminished directional stability.
Due to the degraded flight performance, the crew was forced to perform an emergency landing. During the descent and landing sequence, the Embraer EMB 120 Brasilia struck trees and impacted the ground. A fire broke out following the impact, further damaging the wreckage. The accident resulted in 8 fatalities, including the pilot, and no survivors among the seven passengers.
Findings
Investigations into the left propeller identified that the blade failure was caused by a fatigue crack. This crack originated from several corrosion pits located on the taper bore surface of the blade spar. The crack had spread outward through the blade and around both sides of the taper bore.
At the time of the accident, the specific blade was part of a group of 490 rejected components sent to Hamilton Standard for evaluation and potential repair. Although a borescope inspection protocol had been established following two previous propeller blade separation incidents, the inspection process failed to detect the issue. The primary contributing factor was that the maintenance technicians performing the inspection lacked the necessary non-destructive inspection training and the specialized equipment required to identify the corrosion that led to the fatigue crack.