Accident Overview
A student pilot experienced a catastrophic propeller failure during the takeoff departure. Tower personnel reported that shortly after takeoff, at about 800 feet above the runway, the airplane exhibited a mechanical problem and returned to the runway. Observers noted substantial damage to the front of the engine compartment, with debris scattered on the runway.
Aircraft Examination
Preliminary examination of the airplane revealed a disintegrated propeller hub with the loss of one propeller blade. The crankshaft was severed aft of the shaft flange. The firewall assembly sustained substantial damage, and the engine was pointing downward at approximately 30 degrees.
Pilot Statement
The pilot stated that there were no prior indications of a discrepancy with the engine or airframe during the run-up or takeoff. He reported that the engine ran smoothly until a loud explosion occurred, which he described as 'took off the front end.'
Maintenance History
The last documented annual inspection, required every 12 months per FAR 91.409a(1), was conducted in January 2001. The propeller was installed during a powerplant modification on February 1, 1988, at an airplane tachometer reading of 3,966 hours. It had been overhauled on August 24, 1987, at 1,971 hours. At the time of the accident, the propeller had accrued 313 hours since overhaul, over 14 years prior. The McCauley factory recommended overhaul interval is 1,200 hours or 60 months.
Propeller Examination
Examination of the propeller hub revealed a crack progression from a corrosion pit inside the hub to a point of overload failure. McCauley Service Bulletins 213 and 213A were issued on January 20, 1994, and June 5, 1998, respectively, to provide improved lubrication and corrosion protection, as well as a built-in means of crack detection. According to SB213A, the recommended compliance time for propellers with more than 900 hours or 59 calendar months since last overhaul or penetrant inspection is within the next 100 hours or at the next annual inspection, whichever occurs first.