N7869G

On October 6, 2024, about 2039 Pacific daylight time, a Cessna 172L, N7869G, was substantially damaged when it was involved in an accident near El Monte, California. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot reported that he departed Modesto City-County Airport-Harry Sham Field (MOD) Modesto, California, with a destination of Chino Airport (CNO), Chino, California. While at MOD, the airplane was refueled with about 24 gallons of 100LL aviation fuel. ADS-B data showed the airplane departed MOD about 1710, climbed to about 5,800 ft mean sea level (msl), and proceeded to Meadows Field Airport (BFL), Bakersfield, California, where the pilot landed and subsequently departed about 1928. The airplane then climbed to a cruise altitude between 7,500 and 7,700 ft msl and proceeded toward CNO.

The pilot stated that he was northeast of Burbank, California, about 7,500 ft when the engine lost power. He declared an emergency and turned to the nearest airport, which was San Gabriel Valley Airport (EMT), El Monte, California. The pilot stated that multiple attempts to restart the engine were unsuccessful, and during the forced landing, he “veered off course of the runway” and impacted terrain.

ADS-B data and video of the airplane showed the airplane overflying the runway until about midfield. The airplane turned slightly to the right, then turned 180° while descending. The airplane overflew the runway and landed in the Rio Hondo Wash, a concrete drainage that ran parallel to runway 1. During the landing, the left wing impacted a chain-link fence, which substantially damaged the left wing spar and undercarriage near the engine firewall.

The airplane was equipped with two 19-gallon wing-mounted fuel tanks. Both fuel tanks were drained by recovery personnel, who reported that about 8 gallons of fuel were recovered from the left wing fuel tank, and about 6 gallons of fuel from the right wing fuel tank. Fuel samples revealed a combination of blue-colored liquid, consistent with 100LL aviation fuel, and a yellow-colored liquid, as seen in the figure. The yellow-colored sample tested negative for water and had the smell of fouled automotive fuel. The blue-colored liquid also tested negative for water.

Figure. Samples of fuel recovered from the wing-mounted fuel tanks, fuel lines and fuel strainer.

According to the owner, the airplane was always stored in a hangar, and he did not use automotive gasoline, despite the airplane being modified by a supplemental type certificate for automotive gasoline.

Examination of the fuel system revealed worn rubber seals on both fuel caps. Continuity of the fuel system was established from the wing fuel tanks throughout the system to the carburetor. Visual inspection of the airframe fuel strainer revealed a blue-colored fuel consistent with 100LL, and minor debris. The drain plug from the carburetor bowl was removed and no fuel was observed in the carburetor bowl. The fuel line from the airframe fuel strainer to the carburetor was removed and no fuel was observed. The fuel selector lever was moved to the left fuel tank position, and blue-colored fuel was observed coming from the airframe fuel strainer. The fuel selector lever was then moved to the right fuel tank position, and blue-colored fuel was observed coming from the airframe fuel strainer. The fuel was collected in a clear glass container and tested for water with negative results.

Examination of the recovered airframe and engine revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation. An external fuel tank with 100LL fuel was attached to the engine fuel supply line. The engine was primed and started on the first attempt. The engine ran normally throughout various power settings for about 5 minutes. Both magnetos were checked and operated within normal parameters. The throttle was advanced to full forward, and the engine produced a static speed of about 2,300 rpm.

According to the Pilot’s Operating Handbook for a similar Cessna 172L, with about 38 gallons of fuel, at 7,500 ft msl and engine speed of 2,300 rpm, the airplane had an endurance of about 6.1 hours, and about 640-mile range without reserve, with a fuel consumption rate of about 6.2 gallons per hour. Given the same consumption rate, 24 gallons equated to about 3.8 hours endurance and about 403-mile range. ADS-B data revealed that the accident flight was about 300 miles in distance and about 3.5 hours duration.

A fuel receipt from MOD showed that the pilot purchased 21.9 gallons of 100LL fuel. The airport manager reported no customer complaints of the 100LL fuel around the time of the accident airplane’s refueling. Additionally, the routine testing of the 100LL fuel delivery systems revealed no reports of anomalies either before or after the accident airplane’s refueling. The pilot did not provide any information regarding his preflight inspection of the airplane before departure.