Primary finding
Probable cause
loss of engine power due to fuel exhaustion which resulted from inaccurate fuel consumption calculations. A factor related to the accident was the inaccurately placarded fuel tanks.
Investigator assessment
Analysis narrative
The pilot was within three miles of his intended destination when the airplane experienced a total loss of engine power. The investigation revealed there was no usable fuel in either tank. The pilot had based his fuel consumption calculations on the 32.5 gallon capacity placarded on either tank. The tanks were actually 30.0 gallon tanks with 27.5 gallon usable capacity.
Source record
Factual narrative
On July 15, 1994, about 1130 central daylight time, a Cessna 180, N333QB, sustained substantial damage in a forced landing near Battle Lake, Minnesota. The pilot reported a total loss of engine power. There were no injuries to the commercial pilot or the two passengers aboard the airplane. The personal flight originated at Forest Lake, Minnesota, at 1015, with an intended destination of Battle Lake. No flight plan was filed, and visual meteorological conditions prevailed at the time. The mechanic who examined the airplane stated he drained about 1.5 to 2 gallons of fuel from the left wing, and no fuel from the right wing. Each fuel tank has 2.5 gallons of unusable fuel. Both fuel tanks were placarded 32.5 gallon capacity, but were actually 30 gallon tanks. The pilot stated he made his fuel calculations based on the 32.5 gallon capacity placarded on each tank. The engine started and ran normally when fuel was supplied. -