NTSB Identification: MIA99LA128.
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Accident occurred Wednesday, April 14, 1999 in VERO BEACH, FL
Probable Cause Approval Date: 08/03/2000
Aircraft: Piper PA-44-180, registration: N30397
Injuries: 2 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
While maneuvering the airplane at 4,000 feet above ground level, the flightcrew heard a loud noise from the left engine and saw that the left engine had dropped down about 45 degrees from the normal position. They returned to the departure airport for an emergency landing. When the landing gear was extended the left engine dropped down further. They were unable to maintain directional control due to the drag and made a forced landing in a wooded area. Post crash examination showed the left propeller hub had failed due to fatigue cracking causing a blade to separate. The remainder of the propeller separated when the propeller flange separated due to overstress and the engine dropped down when the engine mount separated due to overstress. The left propeller had sustained damage in a gear up landing 525 flight hours before the accident. The blades were bent beyond repairable limits and scrapped. The hub was inspected and returned to service with new blades. The manufacturer's procedures call for a hub to be retired if the blades receive damage beyond repairable limits and are scrapped.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The improper return to service of a propeller hub by a propeller overhaul company which according to manufacturer's procedures should have been retired due to damage to propeller blades from sudden stoppage. This resulted in undetected fatigue propagation through the hub and separation of a propeller blade in flight. This resulted in overstress separation of the propeller flange and the remainder of the propeller and overstress separation of the engine mount causing the engine to drop down making the aircraft uncontrollable. Full narrative available
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