Casualties unknown

2007-05-04: Cessna 170 (N4217V) — Wasilla, AK

Wasilla, AK, US

On May 4, 2007, a Cessna 170 (registration N4217V) was involved in an aviation accident near Wasilla, AK. Investigators recorded the probable cause as: A total loss of engine power during takeoff initial climb due to fuel contamination, and the pilot's inadequate preflight inspection. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A private pilot lost engine power at 200 feet, turned toward a residential area, clipped a tree, and crashed. The pilot survived. Fuel contamination and corrosion were found throughout the fuel system.

Accident Details

A private pilot departed from a private airstrip for a personal flight. After takeoff, the airplane climbed to about 200 feet above ground level before losing engine power. The pilot initiated a right turn toward the north, descending toward a residential area adjacent to the airport. Witnesses reported that the propeller was not turning just prior to impact. The airplane struck the top of a large tree approximately 300 feet from a residence, then collided with several additional trees before impacting the ground. The fuel tanks were breached during the accident sequence.

Fuel System Examination

Postaccident examination of the fuel system revealed discrepancies. The left inboard tank was nearly full of blue-colored fuel, while the right inboard tank contained only a small amount of fuel. Water detection paste applied to samples from each tank indicated the presence of small amounts of water. The gascolator contained fuel, sediment, a small amount of water droplets, corrosion around the base of the gascolator screen and base, and small globs of a white, opaque, silicone-like grease material. Similar globs were found in the carburetor inlet screen and in the check valve between the gascolator and the carburetor. The interior of the fittings of the fuel supply line from the gascolator to the carburetor exhibited some corrosion. The aft drain fitting could not be opened due to rust and corrosion, while the forward drain fitting yielded fuel from the gascolator.

Engine and Carburetor Testing

The engine was removed from the airframe and installed on a test stand with a replacement carburetor and a wooden club test propeller. It started and ran smoothly, producing full rated rpm. The accident carburetor was separately tested; it held normal fuel pressure without leaking. Disassembly of the accident carburetor revealed dirt, sediment, and small amounts of water in the bowl. The accelerator pump functioned properly, and the floats operated normally without binding.

Aircraft Usage

The airplane had been flown approximately 22 hours in the 2 years preceding the accident.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20070510X00548. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.