The pilot told investigators that he was preparing to fly the Piper PA-18A-150 with a new propeller that had been recently installed. During a few recent experiences, the propeller would get stuck at top dead center and would only turn normally after multiple start attempts.
On the day of the accident at the airport in Dallesport, Washington, the propeller was stuck at top dead center again after an unsuccessful attempt to start the engine.
He walked to the front of the airplane and stood on one of the floats to reposition the propeller. The engine started up immediately and the pilot was seriously injured when he was hit by one of the propeller blades.
According to the airport manager who arrived several minutes after the accident, he observed the ignition switch in the ON position.
The pilot told investigators that he must have forgotten to turn off the magnetos before he moved the propeller.
Probable Cause: The pilot’s failure to disengage the ignition prior to moving the propeller by hand, resulting in the inadvertent starting of the engine.
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This February 2024 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
I know how to get a particular cylinder to top dead center … on the compression stroke of that cylinder. I do not know how to get an engine stuck at top dead center.
I grew up in a town called Sunnyvale. It was re-named because the previous name was Murphy’s Station. You can’t build rockets in Murphy’s Station. It’s against the law.
Yup.!! the engine stopped a some point in the compression stroke, when the starter motor could not supply the torque to rotate the engine to the ignition firing point and past TDC.
A low inertia prop makes the problem worse.
It just needs more amps to the starter motor.!!
It sad to see a low time pilot not careful enough when moving the prop.
The standard starter motor should be able to easily spin this 8.5:1 compression engine.
Either the battery is a low cranking current ‘ peanut size’ battery, or the wire is under size, which should be 2 gauge, and larger if the battery is in the tail cone.
I’ve seen a number of aircraft with high compression engines and a very low AH and cranking current batteries, which have trouble turning over the engine. It’s ok to use the 23 lb Concorde battery. If you’re concerned about the weight, leave out 3 gallons of fuel.
Maybe, better yet, the pilot should lose 20 lb. [ we’re all getting a bit over weight !!]