CEN11LA552

The pilot noticed a loss of engine power while descending to land, and he made several unsuccessful attempts to restart the engine. The pilot was unable to maintain altitude and made a forced landing to rugged, uneven terrain north of the runway. During the landing roll, the airplane struck a gully and flipped over. The pilot said he did not observe any fuel leaking from the airplane after the accident, and a postaccident inspection of the grassy area around and under the airplane revealed no discoloration from fuel exposure. Examination of the fuel system revealed no mechanical anomalies or blockages, and the fuel selector was set to the right fuel tank. A review of fuel receipts and data downloaded from the engine analyzer revealed there should have been about 58 gallons of fuel on board at the time of the accident. However, only 20 gallons of fuel (15 gallons from the right tank and 5 gallons from the left tank) were drained from the airplane. The missing 38 gallons could not be accounted for. Data from the engine analyzer was downloaded and confirmed a loss of engine power, but it did not identify the cause of the loss of engine power. About 1 minute later, both values dropped to zero. When the engine was test run, it started immediately and ran through its full power band without interruption. No mechanical anomalies were noted that would have precluded the engine from operating normally. Even with a discrepancy of 38 gallons, there was still adequate fuel available for the engine to continue operating. It could not be determined what caused the loss of engine power.

HISTORY OF FLIGHT On August 5, 2011, at 1742 central daylight time, a Cessna T210N, N829MB, sustained substantial damage after it made a forced landing to a field after a total loss of engine power about 15 miles northeast of the Rick Husband/Amarillo International Airport, near Amarillo, Texas. The airline transport pilot and two passengers sustained minor injuries and two passengers were seriously injured. The airplane was registered to and operated by Muy Flying, LLC, San Antonio, Texas. An instrument flight rules flight plan was filed for the flight that departed Moore County Airport (DUX), Dumas, Texas, at 1712. Visual meteorological conditions prevailed for the business flight conducted under 14 Code of Federal Regulations Part 91. The purpose of the flight was to fly company executives to conduct site visits in Texas and New Mexico. The flight originated earlier that day in San Antonio, Texas, with its first stop in Amarillo, Texas. From Amarillo they flew to Clovis, New Mexico, and then to Dumas, Texas. From Dumas, they flew to Amarillo, which was the accident flight. According to the pilot, when the airplane was 20 miles from Amarillo, air traffic control cleared him for a visual approach to runway 22, and he initiated a descent from 6,000 feet to 5,000 feet mean sea level (msl). To enter the descent, the pilot reduced manifold pressure from 29 inches to 23 inches, and left the RPM at 2,500. As the airplane began to descend, the pilot noted the descent rate was exceeding 1,000 feet per minute, so he added throttle and adjusted his pitch attitude, but the airspeed continued to decrease and he added more throttle. At that time, he noted the tachometer indicated 2,300 RPM, the manifold pressure was less than 20 inches, and the cylinder head temperature light on the engine analyzer was blinking the "cold" warning. As the airplane descended through 4,800 feet msl (approximately 1,200 feet above ground level), the pilot applied full throttle. The manifold pressure rose to 25 inches of manifold pressure with no noticeable change in thrust. He then applied full rich mixture and checked the fuel gauges. Both tanks indicated approximately 3/4 full. The pilot then turned the fuel pump on with no effect. He confirmed the ignition was on "both" and attempted to re-start the engine, but to no avail. The pilot said that he then switched the fuel selector from the right tank to the left tank and repeated the process, but he still could not get the engine to re-start. The pilot contacted the tower and told him that he would be making a forced landing to a field about 15 miles north east of the airport due to an engine failure. The pilot landed with full flaps and the gear extended on rugged and uneven terrain between a set of power lines and an irrigation system. The airplane touched down on the main gear at 75 knots, ballooned, then settled back onto the ground. The pilot said he applied maximum breaking to avoid losing control, but the vegetation anddown slope of the terrain did not aid in slowing the airplane down. The airplane approached a gully and he applied full back pressure on the control column in an attempt to raise the nose high enough to prevent the airplane from tipping over. The nose gear impacted the other side of the gully and broke off, before the airplane dug into the bank and flipped directly over onto its back. All five people were able to egress the airplane and there was no fire. The pilot reported that he did not observe any fuel leaking from the airplane after the accident. PERSONNEL INFORMATION The pilot held an airline transport pilot rating for airplane single and multi-engine airplane. He also held a certified flight instructor certificate for airplane single and multi-engine airplane, and instrument airplane. His last FAA Second Class medical was issued on July 22, 2011. The pilot reported a total of 4,200 flight hours; of which 25 hours were in the Cessna T210N airplane. WRECKAGE AND IMPACT INFORMATION An on-scene examination of the airplane was conducted by a Federal Aviation Administration (FAA) inspector and a representative of Cessna Aircraft Company. The on-scene exam revealed that the airplane sustained substantial damage to the vertical stabilizer, rudder, and the firewall. The fuel selector was set to the right tank and could not be moved as a result of impact damage. The aircraft salvage crew drained approximately 15 gallons from the right wing fuel tank and 5 gallons from the left wing fuel tank. There was no evidence of any fuel spill at the accident site. The green vegetation under both secured wing caps and also the engine was not discolored from exposure to fuel. The airplane was moved to a secure facility and an additional examination of the airplane was performed under the supervision of the Investigator-in-Charge (IIC). The entire fuel system of the airplane was examined for any blockages or leaks. None were found. The fuel selector was removed and no mechanical anomalies were noted. TESTS AND RESEARCH The engine was test-run at Continental Motors, Incorporated, on October 18, 2011, under the supervision of the Investigator-in-Charge (IIC). The engine started immediately and ran through its full power band without interruption. No mechanical anomalies were noted that would have precluded the engine from operating normally. A JPI EDM-930 engine monitor was removed from the airplane and sent to the NTSB Research and Engineering Laboratory for download and analysis. The EDM recording contained approximately 34 hours of data over 33 power cycles. The last four flights, including the accident flight, were downloaded from the unit. The four flights were automatically assigned a flight number by the EDM (1609, 1610, 1611, and 1612 respectively). Approximately 15 minutes after the unit began recording data for the first flight (1609), the Engine-1 (Eng1) Fuel-Used indication was reset. After the unit was powered for flight 1610, another reset of theEng1 Fuel-Used indication was accomplished. No further resets of the fuel used indications were performed for the remainder of the recorded flights. The Eng1 Fuel-Used parameter information is received from a fuel flow transducer. The purpose of the engine fuel flow transducer is to measure fuel flow into the engine. The EDM does not receive any information from the fuel quantity system on the airplane. The JPI EDM-930 Pilot’s Guide provides the following guidance with regards to fuel management: "For fuel calculations to be accurate, it is imperative that you inform the EDM-930 of the correct amount of fuel aboard the aircraft. Do not rely on fuel flow instruments to determine the fuel level in tanks." The pilot reported that he departed San Antonio with full tanks, for a total of 90 gallons (87 gallons usable). The airplane burned approximately 52 gallons of fuel en route to Amarillo, which was consistent with the fuel burn rate registered on the EDM. In Amarillo, the pilot purchased 30 gallons of fuel, but he could not recall if he visually checked the fuel tanks prior to departure. At the time the airplane departed for Clovis, there shoud have been approximately 68 gallons of fuel on board. The flight to Clovis burned a total of 15 gallons (also consistent with the EDM) and when they departed for Dumas there should have been approximately 53 gallons on board. The flight to Dumas burned approximately 16 gallons of fuel (again, consistent with the EDM), for a total of 37 gallons at the time they landed. The pilot purchased 30 gallons of fuel on Dumas, for what should have been an approximate total of 67 gallons on board when they departed for Amarillo. The pilot said he watched the fueler fuel the airplane at Dumas, but he did not visually check the fuel level prior to departure. According to the EDM, the 29 minute flight to Amarillo burned approximately 9 gallons of fuel, which meant that there should have been approximately 58 gallons of fuel on board at the time of the accident. However, only 20 gallons of fuel was drained from the airplane postaccident. The missing 38 gallons could not be accounted for. The EDM data for the accident flight was plotted into several graphs. The data revealed that the engine exhaust gas temperature (EGT) temperature on all six cylinders dropped abruptly from approximately 1,500 degrees F to approximately 300 degrees in three minutes. During this time, the fuel pressure and the fuel flow levels fluctuated for one minute before the fuel flow returned to the previous cruise level. The fuel pressure only returned to 14 psi versus the previous cruise value of 15 psi. About a minute later both values dropped to zero.