An in-flight fracture of a propeller blade resulting from metal fatigue caused an Atlantic Southeast Airlines EMB-120, a Brasilia, to experience loss of lift and reduced directional control, resulting in a crash landing at Carrollton, Georgia that killed 8 of the 29 persons aboard, the National Transportation Safety Board has found.
As elements of the probable cause, the Board cited the propeller blade's manufacturer, Hamilton Standard, for inadequate inspection and repair techniques. Contributing to the accident, according to the Board, were Hamilton Standard's and the Federal Aviation Administration's failure to require recurrent on-wing ultrasonic inspections for the propellers.
On August 21, 1995, about 12:53 p.m. EDT, an Empresa Brasileira de Aeronautica S. A. (Embraer) EMB-120RT, airplane (N256AS) operated by Atlantic Southeast Airlines Inc., as ASA flight 529, experienced the loss of a blade from the left engine propeller while climbing through 18,100 feet. The airplane then crashed during an emergency landing near Carrollton, Georgia, about 31 minutes after departing from Atlanta. The scheduled flight to Gulfport, Mississippi, carried 26 passengers and a crew of 3. The flightcrew declared an emergency and initially attempted to return to Atlanta, but were unable to maintain altitude and were vectored by air traffic control toward the West Georgia Regional Airport in Carrollton for an emergency landing.
The captain and four passengers sustained fatal injuries. Three other passengers died of injuries during the following 30 days. The first officer, the flight attendant, and 11 passengers sustained serious injuries, and the remaining 8 passengers sustained minor injuries.
Safety issues discussed in the report focused on manufacturer engineering practices, propeller blade maintenance repair, propeller testing and inspection procedures, the relaying of emergency information by air traffic controllers, crew resource management training, and the design of crash axes carried in aircraft. Recommendations concerning these issues were made to the Federal Aviation Administration.
At a public meeting today, the Members of the National Transportation Safety Board determined that the probable cause of this accident was the in-flight fatigue fracture and separation of a propeller blade resulting in distortion of the left engine nacelle, causing excessive drag, loss of wing lift, and reduced directional control of the airplane. The fracture was caused by a fatigue crack from multiple corrosion pits that were not discovered by Hamilton Standard because of inadequate and ineffective corporate inspection and repair techniques, training, documentation and communication.
To prevent similar accidents, the NTSB issued several recommendations to the Federal Aviation Administration, including requiring Hamilton Standard to review the adequacy of its tools, training and procedures for performing propeller blade repairs and require the company to consider long-term atmospheric-induced corrosion. Additionally, Hamilton Standard should be required to review its policies regarding internal communications and documentation of engineering decisions as well as its communications with the FAA.
The Board also examined crash survivability issues and recommended that the FAA issue a warning to air traffic controllers of the need to notify fire and crash rescue personnel when requested by a pilot. Further, evaluation should be done of the necessary functions of a crash ax or other crew extraction tools.