Willow Park, TX, USA
N28578
GRUMMAN AMERICAN AVN. CORP. AA 5B
The pilot reported that he heard a loud noise during cruise flight and that the airplane then started losing altitude. He subsequently conducted a forced landing, which resulted in substantial damage to the airplane. A postaccident examination revealed that the propeller assembly had separated from the engine propeller flange. Four of the six propeller bolts were intact, consistent with the bolts backing out before the propeller separated. The remaining two bolts were unable to transfer the loads from the propeller, and they subsequently failed. The pilot reported that the propeller was removed during the most recent annual inspection, which was completed about 1 year before the accident. The airplane had accumulated about 14 hours flight time since the inspection. Although the airplane maintenance logbook entry for the inspection did not indicate that the propeller was removed or reinstalled, it is likely that the propeller assembly was improperly reinstalled at some point, which resulted in its subsequent in-flight separation.
On January 21, 2014, about 1500 central standard time, a Grumman American AA-5B airplane, N28578, was substantially damaged during a forced landing following an in-flight separation of the propeller near Willow Park, Texas. The pilot was not injured. The airplane was substantially damaged. The airplane was registered to a private individual and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which was not operated on a flight plan. The local flight originated from the Lake Whitney State Park Airport (F50), Whitney, Texas, about 1445. The pilot reported that he heard a loud noise during cruise flight at 2,000 feet mean sea level. He was unable to maintain altitude and subsequently executed a forced landing to the infield of a horse racing track. The airplane encountered a drainage ditch during the landing, which caused the nose and right main landing gears to collapse. A postaccident examination revealed that the two-blade, fixed-pitch propeller assembly had separated from the engine propeller flange. The propeller was recovered about three days later from a pasture located about 8 miles east-southeast of the accident site. The propeller bolts, which were retained by the spinner, were recovered. Four of the bolts were intact, with no apparent damage to either the bolt threads or the propeller flange insert threads. The remaining two bolts had failed with the threaded portion of the bolt retained by the propeller flange insert. The appearance of portions of the fracture surfaces appeared consistent with fatigue failure. Safety wire remnants were recovered with the bolts. Airplane maintenance records indicated that an annual inspection was completed on January 14, 2013. The airframe and engine had accumulated about 32,055 hours total time, with about 14 hours since the annual inspection. The engine had accumulated about 412 hours since overhaul. The pilot informed Federal Aviation Administration inspectors that the propeller assembly had been removed and reinstalled during the most recent annual inspection. However, the maintenance logbook entry did not include a notation regarding the removal of the propeller.
The improper reinstallation of the propeller assembly, which resulted in the subsequent in-flight separation of the propeller.
Source: NTSB Aviation Accident Database
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