MIA07LA039

During cruise flight an 18-inch section of one propeller blade separated as a result of a non-detected fatigue crack. The pilot flew towards the nearest airport based on his on-board GPS, but the beacon and runway lights were out of service. By the time he visually spotted the airport and flew towards the approach end of the runway, he had insufficient altitude to reach it. He landed in the tops of trees approximately 100 yards short of the runway, and exited the airplane. Postaccident examination of the propeller revealed blisters (consistent with the onset of corrosion) near the fatigue origin point. The propeller was last inspected 3 months 1 day earlier; the airplane had been operated for 31.57 hours at the time of the failure.

On January 14, 2007, about 1830 eastern standard time, a Cessna 177, N29888, registered to and operated by Sunburst Aviation, Inc., collided with trees during a forced landing near Carrabelle, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight from Pensacola Regional Airport, Pensacola, Florida, to Clearwater Air Park, Clearwater, Florida. The airplane was substantially damaged and the private-rated pilot, the sole occupant, was not injured. The flight originated about 1730, from Pensacola Regional Airport.

The pilot stated that during cruise flight at 5,500 feet, with the engine operating at 2,500 rpm, he felt a "violent shaking of the aircraft." He reduced the throttle and mixture controls and noted that one of the propeller blades was broken. Unable to communicate, he set the transponder code to 7700 and pushed "ident" to notify air traffic control. Using an on-board global positioning system (GPS) receiver he located the nearest airport, and proceeded towards it. He further stated there were no lights (runway or beacon) at the airport, and by the time he visually located it and flew to approach end of the runway, there was insufficient altitude to land there. He landed in the tops of trees approximately 100 yards short of the runway, exited and walked away from the airplane due to leaking fuel.

Examination of the propeller revealed approximately 2/3 length of one propeller blade separated and was not located. The propeller was sent to the NTSB Materials Laboratory for further examination.

Examination of the propeller at the NTSB Materials Laboratory revealed the fractured blade was missing approximately 18 inches. The fracture surface was oriented chordwise and exhibited 2 distinct features/zones. The first zone which was relatively smooth (consistent with fatigue) started at the trailing edge, and extended towards the leading edge for about 60 percent of the blade chord. The remainder of the blade chord (about 40 percent) exhibited inclined planes consistent with overstress. Further examination of the fatigue fracture surface revealed a discolored area (consistent with oxidation) emanating from the trailing edge and from the cambered surface of the blade. Closer examination of the cambered surface of the blade in the area of the discoloration revealed an indentation consistent with hard particle impact. Blisters consistent with corrosion were located on the cambered surface of the blade adjacent to the trailing edge.

Review of the maintenance records revealed the propeller was overhauled last on December 20, 1997, and installed on the airplane on March 3, 1999. The propeller blades were "dressed and painted" on August 10, 2000. Routine inspections occurred from that point to the last inspection, which occurred on October 13, 2006. The airplane had been operated for 31.57 hours since and 668.63 hours since last inspection and propeller overhaul respectively, at the time of the accident.

At the time of the accident, the medium intensity runway lights and rotating beacon at the airport were out of service; this information was listed in the current version of the Southeast U.S. version of the Airport/Facility Directory.