On April 9, 1999, a Grumman-schweizer G-164B (registration N6673Q) was involved in an aviation accident near Franklinton, LA. Investigators recorded the probable cause as: Loss of engine power for an undetermined reason. A factor was the lack of suitable terrain for the forced landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
An aircraft experienced a loss of engine power during takeoff and initial climb, resulting in an off-airport landing. Investigation found a fuel control diaphragm with two holes, but the exact cause of power loss could not be determined.
Incident
During takeoff and initial climb, the aircraft lifted off about two-thirds of the way down the runway and did not accelerate. The engine sound did not change. The pilot reported that the airplane went down into the trees approximately one-quarter mile from the airport.
Investigation Findings
Functional testing of the fuel pump showed it was capable of producing sufficient pressure and flow at normal operating RPM to properly supply fuel to the fuel control unit for engine operation. However, damage to the aircraft precluded a functional test of the fuel control unit. Disassembly of the unit revealed two holes in the fuel control diaphragm.
The manufacturer stated that the damage to the fuel control was the result of impact damage. The FAA coordinator indicated that a tear in the diaphragm could cause a loss of power. Ultimately, the reason for the loss of engine power could not be determined.