NTSB Factual Report

HISTORY OF FLIGHT

On August 19, 2001, about 0830 eastern daylight time, a Cirrus SR-22, N232CD, registered to Blanchard Aviation, LLC, experienced an in-flight loss of engine power and was substantially damaged during a forced landing in a field near Mitchell, Georgia. Visual meteorological conditions prevailed near the accident area and no flight plan was filed for the 14 CFR Part 91 personal flight. The private-rated pilot and two passengers were not injured. The flight originated about 25 minutes before the accident from Louisville, Georgia.

The pilot verbally stated that he personally filled both fuel tanks the day before the accident from his own fuel tank located at the Burke County Airport, Waynesboro, Georgia. The pilot stated in writing that on the accident date, he and one passenger flew from there to the Louisville Municipal Airport, Louisville, Georgia. After landing following the uneventful 20-minute flight, another person en planed. The flight departed from Louisville about 0805, and during climbout at 6,500 feet mean sea level, he noted "bad weather" depicted on the stormscope ahead of the airplane's flight path. He disconnected the autopilot and turned 90 degrees to the left to avoid the weather; prior to starting the turn it began raining. He reported that approximately 1-2 minutes later the flight encountered a downdraft losing 2,000-3,000 feet of altitude. He maintained the airplane's attitude solely by reference to the flight instruments. The airplane then encountered an updraft during which time the engine quit, and the airspeed decreased. He maintained a nose-low attitude in an effort to descend and reported that the visibility was better at lower altitudes. He turned on the auxiliary fuel pump and placed the mixture control to the full rich position while at the same time maintaining "best glide speed" of 88 knots. Engine power was not restored and he maneuvered the airplane towards a field with full flaps selected. The airplane touched down on the road and traveled into a planted "Millet" field where the airplane collided with a dirt terrace causing the landing gear to separate. The airplane came to rest upright approximately 170 feet from the road. He did not report repositioning the fuel selector.

PERSONNEL INFORMATION

The pilot was issued a private pilot certificate with single engine land rating on May 19, 2000. A review of his pilot logbook that ends with the accident flight entry indicates he logged a total time of 644.0 hours, of which .6 hour and 1.5 hours were logged as actual instrument time and in a ground trainer, respectively.

AIRCRAFT INFORMATION

The airplane was a Cirrus Design Corp., model SR-22 airplane, serial number 0019, that was manufactured on May 9, 2001. It was equipped with a Teledyne Continental Motors IO-550N engine, serial number 685749, that was manufactured on February 19, 2001. The airplane had been operated for approximately 174 hours at the time of the accident since manufacture. The wings were designed as a "wet-wing", each wing having a capacity of 42 gallons (40.5 gallons usable). The airplane is equipped with a fuel caution light that illuminates whenever the quantity of fuel in both fuel tanks drops below 14 gallons. The light will not illuminate if one tank is empty and the other tank has greater than 14 gallons of fuel. Also, with the autopilot engaged, the roll trim motor acts as an autopilot servo and automatically maintains a wings-level attitude.

WRECKAGE AND IMPACT INFORMATION

The NTSB did not travel to the accident site. According to an individual who recovered the airplane, there was no fuel in the right wing and the left wing was found to contain 28-30 gallons; fuel was found in the lines at the fuel selector valve. The individual also reported there was no evidence of fuel leakage from near the point of touchdown to the location where the airplane came to rest (a copy of his statement is an attachment to this report).

Initial examination of the airplane by the FAA inspector-in-charge and the NTSB investigator-in-charge following recovery revealed the fuel selector was positioned to the left tank and was in the detent. The fuel line at the inlet of the fuel metering unit was disconnected and no fuel was found. The "B-nut" of the fuel line at the inlet of the engine driven fuel pump was loosened and fuel was noted to seep. Initial examination of the engine that remained attached to the airframe revealed the crankshaft could not be rotated through 360-degrees; binding was noted. The right magneto remained partially secured to the engine by the ignition leads; the impulse coupling was noted to be broken and a piece of the impulse coupling was found inside the accessory case area. Both fuel tank vents were clear and there were no obstructions of the fuel lines from the center section of the wing into each fuel tank. A temporary fuel source was plumbed into the fuel selector at the left and right inlet fittings. With the fuel selector positioned to each respective side and the auxiliary fuel pump activated, fuel flow was noted from each fuel injector nozzle. The drive coupling of the engine-driven fuel pump was noted to be intact. There was no evidence of fuel leakage from either wing. The rudder trim indicator was found positioned to two units nose left trim. The engine was removed for further examination at the manufacturer's facility.

Examination of the engine with NTSB oversight revealed the paper element of the oil filter had ferrous shavings adhering to it. Additionally, the magnetic sump plug had ferrous debris adhering to it. Several minor scratches of the oil pump cavity were noted. Gouging was noted on the crankcase interior opening where the right magneto would be installed, there was no evidence of damage to the crankcase opening where the left magneto was installed. The left magneto had slippage marks which indicated that the magneto rotated approximately .375 inch. Ferrous material consisting of numerous pieces were observed in the oil sump (the material was retained for NTSB examination). Five teeth of the camshaft gear teeth were damaged. The large cluster gear (crankshaft gear) had two teeth with sections missing; circumferentially the pitch of all gear teeth exhibited evidence of wear/scratches. One tooth of the small cluster gear (crankshaft gear) had one tooth missing approximately 70-80 percent of the tooth. Metallurgical examination of the fracture surfaces of the damaged teeth performed by a metallurgist from the engine manufacturer revealed evidence of overload failure by shearing and crushing forces; no evidence of preexisting failure was noted. There was no evidence of lack of lubrication or crankshaft, camshaft, or valve train failure. Both magnetos were removed for further examination at the engine manufacturer's facility.

Examination of the left magneto with NTSB oversight revealed the impulse coupling body was fractured in three pieces, with pieces missing. Both "trip dogs" of the impulse coupling body were fracture separated. The skid washer was fractured into three pieces, and the main spring was broken. The central cup of the magneto drive gear was distorted/bent. A deep gouge was noted in the magneto housing adjacent to one of the stop pins, and small gouges were noted in the impulse coupling recessed area. both stop pins were in-place. One flyweight of the impulse coupling assembly was fractured; the fractured piece (flyweight tail) was found lodged in the magneto housing. Both axle heads of the impulse coupling cam assembly were noted to be deeply worn at the outer portions. The rotor was noted to freely rotate with the impulse coupling components removed. The broken pieces from the impulse coupling assembly were retained for NTSB Metallurgical examination.

Examination of the right magneto with NTSB oversight revealed the impulse coupling body was fractured into at least four identified pieces. Both "trip dogs" of the impulse coupling body were fracture separated. Both stop pins were fractured, and the skid washer was fractured into three pieces. One flyweight of the flyweight assembly was fractured near the heel and axle areas. The drive bushing cup of the magneto drive gear was damaged; one drive bushing was damaged and one was destroyed. The nose of the fractured flyweight was lodged in the magneto housing adjacent to one of the fractured stop pins. The main spring was noted to be fractured and twisted. The broken pieces from the impulse coupling assembly were retained for NTSB Metallurgical examination.

Metallurgical examination of the components from both magnetos was performed by the NTSB Materials Laboratory located in Washington, DC. The results of the examination of components from the left magneto indicated that with the exception of the fracture surfaces of the main spring, all of the fracture surfaces of the retained components exhibited evidence of overstress separation. Examination of the fracture surfaces of the main spring revealed evidence of six separate fatigue fractures; no obvious mechanical discontinuities were noted at any of the fatigue origins. The main spring was determined to meet the drawing specification for width, thickness, and hardness. The results of examination of components from the right magneto indicated that all fracture surfaces exhibited evidence of overstress separations. Copies of the NTSB Materials Laboratory Factual Reports are an attachment to this report.

TESTS AND RESEARCH

By design of the engine, the magneto operates at 1.5 times of the crankshaft speed. By design of the magneto, the impulse coupling must engage at 150 magneto rpm (100 engine rpm), and disengage at 450 magneto rpm (300 engine rpm). In the range between 150 and 450 magneto rpm, intermittent impulse coupling activation is normal and acceptable. According to the engine maintenance manual, the recommended minimum engine idle speed is 600 rpm. Excerpts from the maintenance manual are an attachment to this report.

According to a representative of the engine manufacturer, the damage and signatures observed to the impulse coupling components of both magnetos were consistent with each magneto being operated over an extended period of time at speeds below 450 magneto rpm. The representative also stated that if the main spring were to break, the magneto to engine timing would change in the late direction which would not allow coupling to stop pin contact. A record of conversation with the representative is an attachment to this report.

Following the investigation of the airplane, it was shipped to the manufacturer's facility for repair evaluation. Examination of the airplane revealed the right fuel tank was compromised in the form of a small crack located in the flap cove area; the left fuel tank was intact. Examination of the roll trim motor actuator located on the left wing revealed the actuator was positioned to the full down position (6-degrees) which was consistent with trimming for a left wing heavy condition. A report from the airplane manufacturer representative is an attachment to this report.

ADDITIONAL DATA/INFORMATION

The airplane minus the retained impulse coupling components was released to Marshall Dean, assistant V.P., USAIG, on April 30, 2002. The retained impulse couplings from both magnetos were also released to Marshall Dean, on September 16, 2002.

NTSB Probable Cause

The poor in-flight planning by the pilot-in-command resulting in the total loss of engine power due to fuel starvation.