MOBILE, AZ, USA
N1565A
Beech F-33A
During climb out the engine began shaking, rattling, and losing power. The flight instructor took the controls and performed an emergency off-airport landing. While on rollout the aircraft sustained substantial damage to the leading edges and lower surfaces of both wings. The engine had been previously inspected IAW TCM 99-3, which required the removal of the No. 1 and 3 cylinders. Upon reassembly of the cylinders, it was necessary to reinstall three snap rings on the crankshaft counterweights at the No. 2 and 5 cheeks. An inspection of he No. 5 cheek revealed that these three snap rings were not fully seated. The signatures on the crankshaft and counterweight were consistent with a counterweight striking the crankshaft. This can only happen if the counterweight pin is not in place. A revision to TCM mandatory service bulletin 99-3C, published on July 27, 1999, now requires that the gap between the snap ring ears be measured to insure that they are properly seated during reassembly.
On January 11, 2000, at 0725 hours mountain standard time, a Beech F-33A, N1565A, lost power and made an off-airport forced landing after conducting a touch-and-go takeoff and landing near Mobile, Arizona. The airplane sustained substantial damage; however, neither the certified flight instructor nor his two private pilot certificated student pilots were injured. The aircraft was being operated as an instructional flight by Airline Training Center Arizona under 14 CFR Part 91 when the accident occurred. The flight had departed Mobile airport (private) about 0723 on the morning of the accident. Visual meteorological conditions prevailed at the time and no flight plan was filed. The instructor reported that the aircraft was on a crosswind climb out after a touch-and-go on runway 09. As the aircraft reached 2,700 feet msl with an airspeed of 120 knots, the engine began shaking, rattling, and losing power. He made a 180-degree turn back toward the airport but realized that they did not have sufficient altitude to reach the runway. He then began looking for an open area in which he could attempt an off-airport landing. After selecting a landing site, the instructor asked the student seated in the left front seat to lower the landing gear, set the flaps, and then to squawk 7700. After touching down, the aircraft rolled about 1,020 feet on a heading of 215 degrees before coming to a stop at 33 degrees 04.85 minutes north latitude and 112 degrees 14.42 minutes west longitude. Federal Aviation Administration (FAA) inspectors found the gear down and locked and the flaps set at 15 degrees with substantial damage to the leading edges and lower surfaces of both wings. They also reported that the engine case was fractured and that a counterweight had separated from the crankshaft. The engine was removed and transported by registered carrier to manufacturer's facility in Mobile, Alabama, arriving on February 14, 2000. On February 22, 2000, the engine was uncrated and disassembled and examined by representatives of the manufacturer under the supervision of an FAA maintenance inspector. A concurrent review of the engine's maintenance records revealed that it had been rebuilt at the manufacturer's facility on May 27, 1998, tested on May 28, 1998, and shipped on May 30, 1998. The engine had accumulated a total of 1,632 hours since being returned to service. On May 4, 1999, the No. 1 and 3 cylinders were removed for inspection in accordance with Teledyne Continental Motors (TCM) mandatory service bulletin (MSB)99-3. An ultrasonic inspection was conducted by a representative of the manufacturer on the same day. The maintenance records also showed the removal of the No. 1 and 3 cylinders on May 11, 1999. The engine had operated an additional 729 hours since the inspection. Upon disassembly, debris consisting of the following items was found: Two A105 counterweight pins; two snap rings; three counterweight plates; counterweight bushing fragments; fragment of a counterweight; fragment of a connecting rod; two connecting rod bearing segments; two pieces of connecting rod bolt; one connecting rod nut; section of counterweight; camshaft gear with rear section of camshaft; one piece of camshaft with the No. 1 exhaust lobe; fragments of crankcase; and two lifters and crankcase lifter bore sections. The oil pump gears and the associated cavities exhibited scratches. The oil pressure relief valve seat contained metal fragments. The No. 1 and 2 cylinder barrel lower skirts were damaged. The No. 1 connecting rod was separated from the crankshaft. The No. 1 piston lower skirt was damaged. The crankcase was damaged in the area of the rear cylinder bays. The crankshaft counterweight at the No. 2 cheek was broken at the aft trailing section. Both counterweight pins, plates, and two snap rings were found in the oil sump. The third snap ring was not located. According to the manufacturer's representatives, the signatures on the crankshaft and counterweight are consistent with a counterweight striking the crankshaft. They stated that this could only happen if the counterweight pin was not installed. The remainder of the damage they attributed to flying debris that occurred after the counterweight separated. An inspection of the No. 5 cheek revealed that the three snap rings were not fully seated. A revision to TCM mandatory service bulletin 99-3C, published on July 27, 1999, now requires that the gap between the snap ring ears be measured to insure that they are properly seated.
the manufacturer representative's improper reinstallation of the crankshaft counterweight snap rings which subsequently separated, allowing the crankshaft counterweight to contact the crankshaft resulting in a total power loss of engine power.
Source: NTSB Aviation Accident Database
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