Accident Overview
On August 19, 2010, about 1200 mountain standard time, a Grumman G-164B, registration N6607Q, collided with terrain during takeoff from a dirt strip near Buckeye, Arizona. The operator, Crawford Aviation Services, was conducting the flight under 14 Code of Federal Regulations Part 137 as an aerial application flight. The commercial pilot sustained serious injuries. The airplane sustained substantial damage from impact forces and a post-crash fire. Visual meteorological conditions prevailed, and no flight plan had been filed.
Pilot Report
The pilot reported having flown the airplane approximately 4.2 hours on the day of the accident. The aircraft was loaded with about 200 gallons of water and insecticide (maximum capacity 315 gallons) and 50 gallons of fuel (maximum 80 gallons). During taxi and run-up, no discrepancies were noted. Takeoff was initiated on runway 16, with normal acceleration, engine indications, and tail liftoff.
After completing about two-thirds of the takeoff roll, the engine revolutions per minute (rpm) increased to 2,600–2,700, exceeding the maximum allowable 2,550. The pilot felt a moderate to severe vibration and immediately initiated an aborted takeoff. He retarded the throttle to idle, applied maximum braking, and held the control stick full aft. As the airplane slowed to 20–30 knots, he steered away from a railroad-tie fence at the runway end, onto hard-packed desert adjoining the west edge of the runway. After rolling a short distance, the left main landing gear entered a depression and sheared off. The airplane settled onto the left wing and was almost immediately engulfed in fire. The pilot egressed through the left window hatch with serious injuries.
Post-Accident Examination
A National Transportation Safety Board investigator examined the wreckage. The engine sustained fire damage to the aft section, exposing the accessory gears. Fire consumed all accessories, including both magnetos. The crankshaft rotated freely with manual propeller rotation; the magneto drive gears rotated. Seven of nine spark plugs had dark brown/black deposits with oval-shaped center electrodes; two spark plugs were oil soaked.
Borescope examination of the cylinder bores showed all piston crowns with light brown deposits, no indication of piston-to-valve contact or catastrophic failure. Valves in the lower cylinders were oil soaked.
Engine controls remained attached at their respective control quadrants; the governor control remained attached at the engine. The burnt remnants of the mixture and throttle control assemblies were within the firewall with connections still attached to the control cables. Outer cables were intact and continuous; fire damage and bends prevented continuity of internal linkage to the cabin.
Fire consumed airframe surfaces from the empennage to the firewall; both upper and lower wings were consumed from mid-wing span inboard. All ailerons and empennage control surfaces remained attached at their hinges. Fire consumed control surfaces in the cabin and inboard wing areas.