Accident Overview
On September 3, 2022, about 1500 mountain daylight time, a Cessna 180, registration N3135D, was substantially damaged when it collided with trees during a forced landing near Seeley Lake, Montana. The pilot and passenger were seriously injured. The flight was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight History
The pilot reported that he filled the fuel tanks before departing from Vance Brand Airport in Longmont, Colorado, and flew direct to Seeley Lake Airport (S23) at a cruise altitude between 10,500 and 12,500 ft mean sea level. During cruise, the pilot leaned the mixture aggressively, aiming for a fuel burn of 9.5 to 10 gallons per hour. The flight was uneventful until the pilot began a descent into the traffic pattern, enrichened the mixture, and applied carburetor heat. While on the downwind leg for runway 16, he estimated 10.5 to 11 gallons of fuel remaining.
The pilot conducted a low approach over runway 16 at an intermediate power setting to inspect the runway for wildlife. As he initiated a climb and turned onto the left crosswind leg, about 300 ft above ground level, the engine lost all power. He executed a forced landing to a nearby clearing, but the airplane struck trees and came to rest in a nose-low attitude.
Postaccident Examination
Examination by a Federal Aviation Administration (FAA) inspector revealed substantial damage to both wings and the fuselage. Photographs showed the bottom of the fuselage had been cut open by an unknown source. The left and right fuel lines from the wing tanks were separated, consistent with impact damage. The wreckage was recovered to a secure location. Recovery personnel reported that no fuel was recovered from either fuel tank.
Inspection of the recovered airframe and engine found no evidence of any preexisting mechanical malfunction that would have prevented normal operation. The fuel selector valve was in the left fuel tank position, and the handle was separated from the valve. Both fuel tanks had crush damage; the left tank's leading edge and a portion were torn open, while the right tank appeared intact. The left and right fuel tank float gauges were intact and placarded “NO TAKEOFF” for ¼ tank or less.
The airplane was equipped with two 30-gallon fuel tanks, of which 27.5 gallons were usable. The airplane owner’s manual states, “a red arc on the face of each indicator, warns the pilot that the respective tank is less than one-quarter full. Do not take off if the pointer is in the red arc.”