Accident Overview
On July 20, 2020, about 2127 eastern daylight time, a Cessna 182A, registration N4092D, was substantially damaged during an accident near Pottstown, Pennsylvania. The pilot, pilot-rated passenger, and passenger were not injured. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 personal flight.
Engine Power Loss
Earlier that day, the pilot and pilot-rated passenger departed Smoketown Airport (N37), Smoketown, Pennsylvania, and flew to Brandywine Regional Airport (OQN), West Chester, Pennsylvania, to pick up a passenger. At OQN, they purchased 7.8 gallons of 100LL aviation gasoline and added it to the airplane. They then departed for Portsmouth International Airport at Pease (PSM), Portsmouth, New Hampshire. After arriving at PSM, they purchased another 20 gallons of fuel. During the return flight, around 2120, the engine lost power. The pilot-rated passenger, who was being "checked out" during the flight, transferred control to the pilot, declared an emergency with Harrisburg approach, and implemented an emergency checklist to troubleshoot the loss of power.
According to the pilot, when they were at 4,500 ft and approaching the Harrisburg area, the engine began to "sputter." The power was set at 22 inches of manifold pressure and 2,300 rpm, then it "spiked" to 2,600 rpm and dropped back to 2,300 rpm. He adjusted the mixture control, but rpm and manifold pressure continued dropping. Applying carburetor heat had no effect. The pilot reported a gradual, continuous loss of engine power starting 5 to 10 minutes before touchdown, with the engine achieving only 1,200 rpm at touchdown. No gauge anomalies were noted, and fuel quantity indication was normal.
Emergency Landing
With no engine power, the pilot made an emergency landing on Route 422, describing it as the best illuminated landing site. According to local law enforcement, the airplane touched down traveling westbound on US Route 422. During the landing rollout, it struck the right rear side of one automobile and the left rear fender of another. Neither driver was injured. The airplane came to rest in the left lane just before the intersection of Daniel Boone Road. No fuel was observed on the roadway, and the airplane displayed damage on its left side.
Post-Accident Examination
An examination of the airplane after the wings were removed revealed that the fuel selector was in the "BOTH OFF" position; however, the fuel selector position before wing removal was not documented. The fuel strainer was clean, full of fuel, and contained no water. The fuel was consistent with 100LL aviation gasoline. The oil filter contained no metallic particles, oil level was correct, and the air filter was serviceable. The carburetor throat was clear of obstructions. Throttle, mixture, and carburetor heat controls showed no discrepancies. Spark plugs and magnetos checked normally. A thumb compression check of all six cylinders indicated good compression. Two engine runs were performed using a 1-quart can attached to the right-wing fuel pick-up; during the second run, rpm was increased to more than 2,400 rpm with no anomalies. Data from the engine data monitor showed no engine anomalies, and cylinder head temperatures, exhaust gas temperatures, oil pressure, and oil temperature were within limits until the engine lost power.
Fuel System Observations
During wreckage retrieval, 5 to 6 total gallons of fuel were removed from the left-wing fuel tank, and the right-wing fuel tank was empty. The mechanic who removed the wings estimated 4 to 5 gallons from the left wing and the right tank dry. A visual examination by an FAA inspector revealed visible dampness on the left-wing fuel tank feed hose and staining consistent with blue dye from 100LL aviation gasoline around the wing separation area. The right-wing hose was dry with no staining. The Cessna 182A Owner's Manual states that 1.5 gallons per tank are unusable, and when not in level flight, an additional 3.5 gallons per tank are unusable. The chief pilot noted that the pilot reported the engine was surging in a nose-low attitude, and he later stated that surging is characteristic of fuel starvation. The pilot acknowledged that he did not top off the tanks at PSM and stated it was a wrong decision.