14 CFR Part 91: General Aviation
Incident occurred Sunday, September 18, 2011 in New Haven, CT
Probable Cause Approval Date: 02/14/2013
Aircraft: BEECH V35, registration: N275BM
Injuries: 2 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
During the climb after takeoff, as the airplane approached 6,000 feet mean sea level, the crankshaft fractured, and the airplane experienced a total loss of engine power. The forward portion of the crankshaft, with the propeller attached, departed the engine. The pilot declared an emergency and returned to the departure airport where he performed a forced landing on a runway. The airplane sustained minor nose gear damage when it overran the runway. Examination of the crankshaft revealed that it was fractured across the No. 4 main journal. Metallurgical examination revealed cracks that initiated on the bearing surface near an oil transfer tube and propagated in fatigue.
At the time of the incident, the engine had been operated for about 910 total hours, about 500 hours of which had occurred since maintenance, which was performed about 2 1/2 years before the incident and included the reinstallation of the Nos. 2 and 4 cylinders. The crankcase adjacent to the fractured portion of the crankshaft showed significant fretting on the mating surfaces, possibly due to incorrect torque applied during the previous cylinder repair; however, the investigation could not determine the relevance of that repair, if any, due to the time that had elapsed since the repair was completed.
The National Transportation Safety Board determines the probable cause(s) of this incident to be:
The in-flight fatigue failure of the engine’s crankshaft, which resulted in the separation of the forward portion of the crankshaft and the propeller.
On September 18, 2011, about 1035 eastern daylight time, a Beech V35, N275BM, operated by a commercial pilot, sustained minor damage during a forced landing, following a total loss of engine power shortly after takeoff from the Tweed-New Haven Airport (HVN), New Haven, Connecticut. The certificated commercial pilot and a passenger were not injured. Visual meteorological conditions prevailed and an instrument flight rules flight plan was filed for the personal flight that was conducted under the provisions of 14 Code of Federal Regulations Part 91.
According to the pilot, the airplane departed HVN and began to climb without incident. As the airplane approached 6,000 feet mean sea level, the pilot felt a shutter and slight change in engine rpm. A few seconds later, he experienced oil on the windscreen, smoke, and engine roughness, followed by a total loss of engine power. The pilot declared an emergency and was able to return to HVN to perform a forced landing to runway 14. During the landing, the airplane sustained minor nose gear damage when it overran the runway about 50 feet, and came to rest in weeds.
The airplane was powered by a Teledyne Continental Motors IO-550-B83, 300-horsepower engine, equipped with a three-bladed Hartzell constant-speed propeller.
Examination of the airplane by a Federal Aviation Administration inspector revealed that the propeller and forward portion of the crankshaft, aft of the propeller mounting flange, separated inflight and was subsequently located in a wooded area. The engine and the separated portion of the crankshaft were retained for further examination.
A teardown of the engine conducted at Continental Motors Inc., Mobile, Alabama, under the supervision of an NTSB investigator, revealed that the crankshaft and counterweight assembly exhibited lubrication distress, thermal damage, and mechanical damage on all six connecting rod journals. The crankshaft was fractured in two-pieces across the No. 4 main journal. The crankcase main bearing supports adjacent to the fracture exhibited fretting signatures and lock-slot elongation. The No. 4 main bearing was extruded, with portions found in the oil sump. Metallurgical examination of the fractured crankshaft revealed cracks initiated on the bearing surface near an oil transfer tube and propagated in fatigue. Cracks were also identified on the bearing fillet radius.
At the time of the incident, the airplane had been operated for about 5,470 total hours, and 14 hours since its most recent annual inspection, which was performed on August 11, 2011. The engine was manufactured during November 2006, and had been operated for about 910 total hours. In addition, the engine had been operated for about 500 hours since maintenance was performed that included the reinstallation of the Nos. 2 and 4 cylinders after repair, on February 17, 2009.
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NEW HAVEN — An unidentified pilot and passenger were uninjured this morning when a single engine plane overshot a runway at Tweed New Haven Airport, according to a Federal Aviation Administration spokesman.
Jim Peters, an FAA spokesman based in New York said the incident occurred at 10:30 a.m., just minutes after the fixed-wing plane had taken off from Tweed. As it was headed to an unspecified New York area airport, the pilot radioed to air traffic controll based on Long Island that the plane had developed engine trouble and that he was returning to Tweed, Peters said.
As the pilot was making the landing, the plane ran out of runway and travelled 150 feet before coming to rest near a brushy area on the East Haven side of the airport, according to Peters. Tweed straddles the border between the city of New Haven and East Haven.
“We’ll have investigators from our Windsor Locks office take a look at it,” Peters said. “If the damage is so significant that the plane can’t be salvaged, then the National Transportation Safety Board will be called in.”
The plane, a Beech 35, was registered to the Westchester Flying Club in Purchase, N.Y., one of seven planes the organization makes available for rental at between $182 and $192 per hour, according to the group’s web site. Officers of the club were not immediately available for comment on Sunday
The club is based at the Westchester County Airport in Purchase. According to FAA records available online, the plane involved in the incident was manufactured in 1966.
