Register

The Propagation of a Broken Crankshaft

The fatigue crack had been with us from the start, biding its time, nibbling at the heart of the engine.

The author with Robert Parke in "Melmoth," circa 1974. [Photo courtesy of Peter Garrison]
Gemini Sparkle

Key Takeaways:

  • A pilot experienced subtle, escalating engine issues during a flight, which were initially misdiagnosed and "repaired" as a stripped magneto timing gear after an emergency landing.
  • Despite the initial repair, the engine continued to perform poorly, leading to a full engine teardown that ultimately uncovered a broken crankshaft.
  • The crankshaft failure was a classic fatigue break originating from a tiny inclusion, demonstrating how critical mechanical issues can manifest subtly over extended periods, posing significant latent danger.
See a mistake? Contact us.

It was the spring of 1979. Robert Parke, then FLYING’s editor, was in Los Angeles. His next stop was Reno, and of course I offered to fly him there. My homemade airplane, Melmoth, had by then successfully crossed both the Atlantic and the Pacific, and so the intrepid Parke, who had piloted B-17s over Europe in World War II, was willing to chance it.

It was a clear, calm day. We climbed out of Whiteman Airport (KWHP) and through the Newhall Pass, turning northwestward toward Gorman. I leveled out at 10,500 feet. Mount Pinos crept past our left wing and the vast flatness of the San Joaquin Valley lay fading into the haze before us.

Peter Garrison

Peter Garrison taught himself to use a slide rule and tin snips, built an airplane in his backyard, and flew it to Japan. He began contributing to FLYING in 1968, and he continues to share his columns, ""Technicalities"" and ""Aftermath,"" with FLYING readers.

Ready to Sell Your Aircraft?

List your airplane on AircraftForSale.com and reach qualified buyers.

List Your Aircraft
AircraftForSale Logo | FLYING Logo
Pilot in aircraft
Sign-up for newsletters & special offers!

Get the latest stories & special offers delivered directly to your inbox.

SUBSCRIBE