BULLHEAD CITY, AZ, USA
N7774G
Cessna 172L
During the takeoff departure the student pilot experienced a catastropic failure of the propeller. Control tower personnel reported that shortly after takeoff, about 800 feet above the runway, the airplane experienced a mechanical problem and returned to the runway. They also noted substantial damage to the front of the engine compartment with debris scattered on the runway. Preliminary examination of the airplane revealed a disintegrated propeller hub with loss of a propeller blade and a severed crankshaft aft of the shaft flange. Substantial damage was evident to the firewall assembly with the engine pointing down about 30 degrees. The pilot stated that there were no prior indications of a discrepancy with the engine or airframe during the run-up or takeoff. He said that the engine ran smoothly until there was a big explosion that "took off the front end." The last documented annual inspection occured in January 2001; an inspection that is required every 12 months per FAR 91.409a (1), as are other inspections and procedures. According to records, the propeller was installed on the airplane during a powerplant modification February 1, 1988, at airplane tachometer reading of 3,966 hours. The propeller had been overhauled 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 is 1,200 hours or 60 months. 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 January 20, 1994, and June 5, 1998, 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 greater than 900 hours or 59-calendar months since last overhaul/penetrant inspection is within the next 100 hours, or at the next annual inspection, whichever occurs first.
HISTORY OF FLIGHT On March 7, 2002, at 1407 mountain standard time, a Cessna 172L, N7774G, experienced a propeller blade failure during departure from the Bullhead City/Laughlin International Airport, Bullhead City, Arizona. The student pilot landed on the remaining runway and overrun area. Neither the pilot nor his passenger were injured. Examination of the airplane revealed substantial damage had occurred to the airplane structure. Visual meteorological conditions prevailed for the originating personal flight operating under the provisions of 14 CFR Part 91, and no flight plan was filed. Control tower personnel reported that shortly after takeoff from runway 16, about 800 feet above the runway, the airplane experienced a mechanical problem and returned to the runway. They also noted damage to the front of the engine compartment with debris scattered on the runway. Preliminary examination of the airplane revealed a disintegrated propeller hub with loss of propeller blades and a severed crankshaft aft of the shaft flange. Substantial damage was evident to the firewall assembly. The engine was pointing downward about 30 degrees, suspended by engine controls and hoses. A Federal Aviation Administration (FAA) inspector interviewed the pilot. The pilot stated that there were no prior indications of a discrepancy with the engine or airframe during the run-up or takeoff. He said that the engine ran smoothly until there was a big explosion that "took off the front end." PERSONNEL INFORMATION According to logbook information, the student pilot was found competent to make safe solo flights in a Cessna 172 on February 25, 2000, valid for 90 days, and again on June 13, 2001. He was found competent to perform solo cross-country flights on March 5 and March 10, 2000. According to FAR 61.83(c) a student must hold at least a current third-class medical certificate issued under part 67 of this chapter. The pilot's last recorded third-class flight physical occured on June 13, 1999. According to FAR 61.89a (2), a student pilot may not act as pilot-in-command of an aircraft that is carrying a passenger. AIRCRAFT INFORMATION The last documented annual inspection of the airplane occured in January 2001, an inspection that is required every 12 months per FAR 91.409a (1), as are other inspections and procedures. According to records, the propeller was installed on the airplane during a powerplant modification February 1, 1988, at airplane tachometer reading of 3,966 hours. The propeller had been overhauled August 24, 1987, at 1,971 hours. At the time of the accident the propeller had accrued 313 hours since overhaul, over 14 years ago. The McCauley factory recommended overhaul is 1,200 hours or 60 months. Examination of the propeller hub revealed that cracks progressed from a corrosion pit inside the hub to a point of overload failure. McCauley Service Bulletins 213 and 213A were issued January 20, 1994, and June 5, 1998, to provide improved lubrication and corrosion protection, as well as a built-in means of crack detection. According to SB 213A, the recommended compliance time for propellers greater than 900 hours or 59-calendar months since last overhaul/penetrant inspection is within the next 100 hours, or at the next annual inspection, whichever occurs first. ADDITIONAL INFORMATION The owner/operator failed to file or return a Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2.
The pilot's failure to comply with maintenance/inspection requirements that resulted in a propeller failure.
Source: NTSB Aviation Accident Database
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