N761KC

HISTORY OF FLIGHT

On February 15, 2000, at 2024 hours mountain standard time, a Cessna T210M, N761KC, collided with ground obstructions and nosed over during a forced landing near Elfrida, Arizona. The forced landing was precipitated by a catastrophic engine failure during cruise. The airplane was operated by the Department of the Treasury, U.S. Customs Service, as a public-use airplane under 14 CFR Part 91 of the Federal Aviation Regulations. The airplane sustained substantial damage. The two pilots, the sole occupants, were not injured. Visual meteorological conditions prevailed and a company visual flight rules flight plan was filed. The flight originated from Davis-Monthan Air Force Base, Tucson, Arizona, at 1940 as a training flight.

According to information provided by the U.S. Customs Service and the pilots, the flight left the US Customs Tucson Air Operations base at Davis-Monthan AFB for a training flight in the Douglas, Arizona, area. No discrepancies were noted with the run-up at Davis-Monthan AFB or until the engine problem happened. The pilot said he was at 5,100 feet msl and using a power setting of 30 inches of manifold pressure and 2,600 rpm. Both pilots heard a loud bang, like a hammer hitting the inside of the engine, which was followed by severe vibrations and sparks emanating from the front of the airplane. According to both crewmembers, the vibrations were constant; however, when the pilot powered back the vibrations seemed to intensify. The pilot reported that from the sparks he thought they might have lost a portion of a propeller blade and began looking for a place to land. They were over a highway running through a built up area, but the pilot considered that there was a likelihood of power lines over and around the highway. They saw a dirt road reflecting in the moon light and set up for a landing there.

On short final to the road, the pilot had to maneuver to the left in order to miss a large tree on the right-hand side of the road. As the pilot maneuvered back to the center of the road, the right wing began to contact trees on the roads right shoulder, which slued the airplane into a drainage ditch. It contacted a barbed wire fence and several other trees, and then nosed over.

Ground witnesses reported observing sparks emanating from the cowl area as the airplane descended toward the road.

Gross external visual assessment of the engine disclosed a large hole in the engine case on each side of the upper spine between the numbers 1 and 2 cylinders and a quantity of oil on the fuselage from the firewall aft to the tail.

PERSONNEL INFORMATION

The pilot holds a commercial pilot certificate with airplane ratings for single engine land, multiengine land, and instruments, and also ratings for rotorcraft helicopters and instrument helicopter. In addition, his certificate is endorsed for private privileges in gliders limited to aero tow only. The most recent issuance of the certificate was August 8, 1998. The most recent second-class medical certificate was issued on October 11, 1999, without limitations. He is employed by US Customs as a pilot and flies both fixed wing and helicopters for the service. The pilot's total time was 4,151 hours, of which 3,395 were accrued in helicopters, with 22 hours in the Cessna T210. His total night experience was 722 hours. According to US Customs records, he completed a standardization check ride on October 23, 1999, which also covered the requirements of a biennial flight review. In addition, he completed an instrument competency check and a check out in the Cessna T210 on February 3, 2000.

The second pilot is also employed by US Customs as a fixed wing and rotorcraft pilot, and holds an Airline Transport Pilot certificate with an airplane multiengine land rating and type ratings for the Beech 200 and Cessna 500. In addition, his certificate is endorsed for commercial privileges in single engine land airplanes, rotorcraft helicopters and instrument helicopters. His most recent first-class medical certificate was issued without limitations on May 13, 1999. According to Customs records, he has accrued a total time of 1,950 hours, of which 550 were in helicopters, with 18 in the Cessna T210. His most recent US Customs standardization check ride was accomplished on August 30, 1999, in a Cessna 550.

Both pilots were wearing shoulder harnesses; however, they did not have helmets.

AIRCRAFT INFORMATION

The Cessna T210M aircraft, serial number 21062308, was operated by US Customs and maintained on an annual/100-hour inspection program. A contractor, Raytheon Aerospace Company, a Federal Aviation Administration (FAA) certificated Repair Station, performed the maintenance on the aircraft and engine at the Tucson Air Branch base, and at a facility in Phoenix, Arizona.

The maintenance records were reviewed. At the time of the accident, the airframe had accumulated a total time in service of 5,579 hours. The airplane flew approximately 30 hours per month on a historical average. A 100-hour inspection was completed on the morning of the accident at the Phoenix maintenance facility. The aircraft was then ferried down to the Tucson base and was dispatched on the accident flight. The records disclosed that there were no unresolved maintenance discrepancies or open items at the time of departure.

The airplane was refueled prior to departure on the accident flight from a USAF truck with 100LL aviation gasoline. Fuel samples were taken from the refueling truck and from the aircraft, and sent to the USAF laboratories at Wright Patterson AFB for analysis. The sample from the truck met specification ATSM D-910 for 100LL aviation gasoline. The sample from the aircraft wing tank met all specifications except for sulfur content, which exceeded the maximum allowable percent/mass by 0.14.

The historical maintenance and rebuild records for the engine were examined. The Teledyne Continental TSIO-520-R engine, serial number 293964-R, was rebuilt by the Continental factory to zero time tolerances on March 20, 1998. The engine was then shipped to Raytheon Aerospace Services and installed in N761KC on May 15, 1998, at an airframe total time of 5,106 hours. A 100-hour inspection was completed on the engine on the morning of the accident.

FAA Priority Letter Airworthiness Directive (AD) 99-09-17 was issued on April 22, 1999, and mandated compliance with Teledyne Continental Motors Mandatory Service Bulletin (MSB) 99-3 for specific engines identified by serial number. The accident engine was subject to both the AD and the MSB. AD 99-09-17 was subsequently superceded by AD 99-19-01 on September 30, 1999; however, the applicability provisions remained the same.

The AD and the MSB were issued due to a history of 8 crankshaft failures (the 8 fractured crankshafts were as of July 27, 1999), which were traced to a Teledyne Continental factory manufacturing process involving the installation of crankshaft counterweight bushings on the crankshaft counterweight hangar blade. According to the MSB, the manufacturing process discrepancy produced a condition, which induced a crack and catastrophic fracture of one or more crankshaft cheeks. The AD and MSB required visual and ultrasonic inspections of the identified crankshafts for cracks. The AD and MSB mandated that these inspections be accomplished by Teledyne Continental factory service representatives.

Three versions of MSB 99-3 were eventually issued: 99-3A was issued on April 22, 1999; 99-3B superceded 99-3A and was issued on July 6, 1999; 99-3C was issued on July 27, 1999, and superceded 99-3B. All three versions of MSB 99-3, and AD's 99-09-17 and 99-19-01, are appended to this report for reference. An additional Teledyne Continental Service Bulletin, SB 00-3, and pertinent pages from the TSIO-520 overhaul manual are also appended to provide the reader with illustrations of the parts and components referenced herein for clarity. Continental SB 00-3, which was issued on February 2, 2000, provided detailed and specific procedures for the reinstallation of crankshaft counterweights, including the correct orientation and installation of the counterweight pins, retainer plates, and snap rings.

In pertinent part, the TSIO-520 crankshaft is designed to incorporate four counterweights, which are installed on hangar blades extending out on each side of the numbers 2 and 5 crank cheeks (CC). The number 2 crank cheek is between the number 1 and 2 rod journals (RJ) at the rear of the crankshaft. The number 5 crank cheek is located between the number 3 and 4 rod journals. The hangar blades are on each side of the designated crank cheeks. With the number 1 rod journal at the 12 o'clock position and looking forward from the rear of the crankshaft, the hangar blade nomenclature is as follows: 1) the blade on the right side of CC2 is the number 2 leading blade and the counterweight is the number 2 leading weight; 2) The blade on the left side of CC2 is the number 1 trailing blade and weight; 3) The blade on the upper side of CC5 (CC5 is nearly horizontal with the No. 1 RJ at 12 o'clock) is the number 4 leading blade and weight; and 4) the blade on the lower side of CC5 is the number 3 trailing blade and weight.

The crankshaft counterweight hangar blades have two holes bored, and bushings are pressed into these bores. The weights have corresponding holes bored with bushings pressed into them and are retained on the blades by pins, which extend through the blade bushing and into the weight bore bushings. The pins are held in the bores by counterweight pin retaining plates placed in the bores on each side of the weight. These plates are slightly elliptical on one edge of the circumference, which forms an ear that results in an interference fit within the bores of each weight. The plates are held in place by snap rings that fit into separate grooves machined into the weight bores. The weigh...