FTW99LA113

During the takeoff/initial climb, 'the aircraft lifted off about 2/3 of the way down the runway and did not accelerate.' The 'engine sound did not change.' The pilot reported the airplane 'went down into the trees' 1/4 mile from the airport. Functional testing of the fuel pump showed the fuel pump was capable of putting out sufficient pressure and flow at normal operating rpm to properly provide fuel to the fuel control unit to operate the engine. Damage precluded a functional test of the fuel control unit. Disassembly of the unit revealed 2 holes in the fuel control diaphragm. The manufacturer stated 'the damage to the fuel control is the result of impact damage.' The FAA coordinator stated that 'a tear in the diaphragm could cause a loss of power.' The reason for the loss of engine power could not be determined.

On April 9, 1999, at 0900 central daylight time, a Grumman-Schweizer G-164B agricultural airplane, N6673Q, was destroyed following impact with trees and terrain during the takeoff/initial climb near Franklinton, Louisiana. The airplane was registered to and operated by Paynes Flying Service, Inc., of Brandon, Mississippi, under Code of Federal Regulations (CFR) Part 137. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed for the local aerial application flight for which a flight plan was not filed. The flight was originating from runway 17 at the Franklinton Municipal Airport at the time of the accident.

The operator and the pilot reported that the airplane was loaded with 3,500 pounds of fertilizer and the fuel tanks topped for the first flight of the day. Low clouds at 2,000 feet had started to break up, the winds were light and variable, with a temperature of approximately 73 degrees Fahrenheit. The pilot taxied the airplane for departure to the south. The pilot stated that "the aircraft lifted off about 2/3 of the way down the runway [3,000 feet long], and did not accelerate." The pilot further stated that the "engine sound did not change."

The pilot started dumping the load of fertilizer, leveled the airplane, and turned into the wind for the forced landing. He stated that the airplane "did not have enough airspeed to stay up [and] then went down into the trees" 1/4 mile south of the airport.

The FAA inspector and the operator examined the aircraft and found structural damage throughout the airframe.

The fuel control unit and the fuel pump were removed from the Garrett TPE-331-6-252M turbine engine and forwarded to the respective manufacturers for examination under the surveillance of a FAA inspector. Functional testing of the fuel pump showed the low rpm, low-pressure flow was zero. The pump ran on the test bench "without any unusual noises or fluctuations." According to the manufacturer, "the fuel pump was capable of putting out sufficient pressure and flow at normal operating rpm to properly provide fuel to the fuel control unit to operate" the engine. The manufacturer further stated that the no flow at low rpm "was probably due to the broken carbon bearing which is typical of a prop[eller] strike." See the enclosed report for additional details. The FAA inspector concurred that the "pump had no fuel discharge at the minimum RPM."

Damaged precluded a functional test of the fuel control unit; therefore, the unit was disassembled. Examination of the fuel control diaphragm revealed two holes. According to the manufacturer, the teardown examination revealed "that the damage to the fuel control is the result of impact damage. See the enclosed report for additional details. The FAA coordinator stated that "a tear in the diaphragm could cause a loss of power."

A review of the maintenance records revealed that the last annual inspection was performed on October 20, 1998. The engine was removed in June 1998 due to metal in the chip detector and oil filter. Following an oil and filter change, the engine was run in a test cell and then reinstalled on the airframe. The firewall fuel filters and fuel pump inlet filter were replaced on April 3, 1999. The overhauled flow divider, installed in February 1999, was also replaced on April 3, 1999. An oil sample was taken for analysis; however, data of the analysis was never made available to the NTSB investigator-in-charge. In March 1999, the fuel control was replaced with unit serial number 1294294 with 3,719.9 hours.