On August 16, 1998, a Schweizer G164B (registration N7502A) was involved in an aviation accident near Newton, MS. Investigators recorded the probable cause as: The erosion of the compressor impeller and the unsecured fuel control unit resulted in the loss of engine power during the initial climb. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During agricultural operations, a pilot experienced engine power loss after noticing slow spool-up. Despite dumping the load and applying full throttle, the descent could not be arrested, resulting in a collision with trees during a forced landing.
Accident Details
The pilot of an agricultural aircraft reported that he had completed approximately 13 loads of agricultural products before the incident. While preparing for another takeoff, he observed that the engine was slow to spool up to 100%. During the climb-out, the pilot noted insufficient power to maintain the climb. He advanced the throttle to the full forward position and dumped his load, but he could not arrest the descent. The pilot executed a forced landing, during which the airplane collided with trees.
Engine Examination
Post-accident examination of the engine assembly revealed that the first stage compressor wheel showed evidence of erosion. Fresh dirt and debris were found in the first stage compressor assembly. Several stator vanes exhibited pre-impact bending associated with erosion.
Fuel Control Unit Examination
Further examination of the engine assembly disclosed that the fuel control unit rear support bracket bolt was not installed. The fuel control unit was displaced approximately 1/4 inch from its normally installed position. Examination of the fuel control unit showed chaffing on the pump flange.