The pilot told investigators that during the preflight inspection of the Piper J-3C, no anomalies were noted.
He decided to use Runway 9 for the departure at Lewis University Airport (KLOT) in Romeoville, Illinois, for the local flight.
During takeoff, at about 650 feet AGL, the airplane began to shake “very violently.”
The pilot closed the throttle, issued an emergency transmission to the KLOT air traffic control tower, and executed a 180° turn to the left to land back on the departure runway.
About halfway through turn, he turned off the engine as he felt the airplane could successfully make the landing. He was able to land on the runway without further incident.
After he exited the airplane, he noticed that about 5 inches of the outboard portion of one of the aluminum propeller blades had separated. The separated blade segment was not recovered. There was no other damage sustained to the propeller, the engine, and the airframe. The airplane was equipped with a McCauley 1B90/CM7144 fixed pitch propeller.
Post-incident examination revealed features consistent with fatigue cracking initiating at the midpoint of the cambered face of the propeller blade. These initiation sites exhibited corrosion pits consistent with those found on the cambered face of the propeller, which had been present underneath the paint and primer.
An annual inspection was performed on the airplane on Oct. 25, 2022, about five months before the crash. A review of the maintenance records revealed that the airplane had accumulated 0.7 hours since the annual inspection was performed.
The propeller was overhauled on Jan. 28, 2015, and the total time since new was listed as “unknown.” The propeller was installed on the airplane on Aug. 18, 2015.
The propeller had about 223 total hours since its installation. The maintenance records did not show any overhaul work performed on the propeller since it was installed on the airplane.
According to McCauley, this propeller is to be overhauled at 2,000 hours or 72 calendar months, whichever occurs first. The FAA does not mandate that propellers be overhauled for 14 CFR Part 91 operations.
Probable Cause: The inflight failure of the propeller blade due to fatigue cracking from corrosion pits, initiating at the midpoint of the cambered face.
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This April 2023 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.
72/12 is 6 not 7 years.
Yes it is…I’ll ‘stretch ‘ it a year.
[ and just to see if anyone read this ]
Also, I have the FAA PMAd ‘prop guard’ tape on the leading edge, so the prop still looks like new.!
I have 1st hand experience that aluminum props don’t last forever.
My Cessna had 4,000 hrs on it and from the logs, so did the prop.
So, we removed the prop and sent it for overhaul. After their tests they found a crack in the center bore, in line with a bolt hole. It was red tagged, and would have fialed soon.
The shop found a prop to overhaul . So after the 7 years, it will come off and go for overhaul