New Castle, VA, USA
N92804
CESSNA 172M
The pilot reported that, before departure, he performed an engine run-up and then initiated takeoff from the 2,400-foot-long upsloping grass runway in accordance with soft-field takeoff procedures. The airplane was slow to produce speed; but, it lifted off the ground. Although the pilot attempted to fly in ground effect to produce more speed, he soon realized that he did not have enough speed or altitude to clear trees beyond the runway, so he maneuvered the airplane toward a clearing where he intended to land the airplane. However, the airplane then stalled, the left wing tip contacted the ground, and the airplane cart-wheeled. The pilot further reported that he should have recognized the "sluggish speed sooner and [aborted the] takeoff." Examinations revealed that the magnetos were slightly out of timing and that both of the No. 2 cylinder's spark plugs contained lead and carbon deposits; however, it could not be determined how this affected engine power or whether these conditions would have been noticeable to the pilot during the engine run-up before departure or during the takeoff. Examinations revealed no anomalies that could have precluded normal operation. Postaccident performance calculations indicate that, based on the airplane's weight, the reported headwind component, and takeoff from a grass runway, the total distance to clear a 50-foot obstacle was 914 feet; therefore, the pilot should have been able to clear the trees.
On April 7, 2013, about 1445 eastern daylight time, a Cessna 172M, N92804, registered to and operated by Mayberry Aviation Inc., collided with terrain during takeoff from New Castle International Airport (VA85), New Castle, Virginia. Visual meteorological conditions prevailed at the time and a visual flight rules (VFR) flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal flight from VA85 to Mount Airy/Surry County Airport, Mount Airy, North Carolina. The airplane sustained substantial damage and the private pilot and two passengers were not injured. The flight was originating at the time of the accident. The pilot stated that the engine start and run-up were satisfactory so he taxied to runway 18 for departure; the wind at the time was from the south at 15 knots. With all available runway ahead, he initiated takeoff from the upslope runway with 5 degrees of flaps extended and soft field takeoff procedures. He noted that the airplane was, "slow to produce speed but finally broke ground where I attempted to fly in ground affect to produce more speed…" Shortly thereafter he noticed the windsock at the end of the field and knew he did not have enough speed or height to clear trees beyond the runway. He turned to the left towards a clearing where he intended on landing the airplane. As the flight crossed a pond, he lost "ground affect" so he lowered more flaps and pushed the control column to generate enough speed to clear the pond. As the flight reached the opposite side of the pond, the airplane stalled causing the left wing tip to contact the ground. The airplane cart wheeled and after coming to rest, the pilot secured the aircraft and all occupants exited the airplane. He further stated in the recommendation section of the NTSB Pilot/Operator Aircraft Accident/Incident Report that he should have recognized the, "…sluggish speed sooner and [abort the] takeoff…." Following recovery of the airplane the engine was inspected by FAA airworthiness personnel which revealed crankshaft, camshaft and valve train continuity; however, a slight binding was noted during rotation of the crankshaft. The throttle, mixture, and carburetor heat controls operated normally with no binding and traveled stop to stop. No discrepancies were noted with the air induction system or exhaust system components that would cause a loss of engine power. Cold differential compression of the cylinders was performed and the Nos. 1 through 4 cylinders measured 30, 0, 50, and 45 psi, respectively. During the differential compression testing of the Nos. 1 and 2 cylinders specifically, air leakage from the intake valve and in the crankcase was noted, while the air leakage past the intake valve of the No. 2 cylinder was documented to be a, "big leak." During the testing of the No. 2 cylinder, staking of the intake valve was done multiple times with minimal results. Inspection of the spark plugs from the No. 2 cylinder revealed the lower spark plug contained material that was light brown to beige in color, while the upper plug had a chipped insulator next to the center electrode. Both magnetos were tightly installed on the accessory case, and were timed together between 18 and 20 degrees before top dead center (BTDC). The engine data plate indicates the timing should be 25 degrees BTDC. Both magnetos were inspected and appeared to be in good condition. The No. 2 cylinder upper and lower spark plugs were retained for further examination. A copy of the FAA inspection report is contained in the NTSB public docket. A representative of the engine manufacturer reported that they are unable to provide the estimated loss of power due to the as-found timing of the magnetos, and they were also unable to estimate the effect of magneto drop off based on the many variables that may exist between aircraft installations. Examination of the upper and lower spark plugs from the No. 2 cylinder was performed by the NTSB Materials Laboratory, located in Washington, D.C. As part of the testing, the debris removed from the submitted spark plugs was examined using Energy Dispersive spectroscopy (EDS) which showed carbon (C), lead (Pb), aluminum (Al), and oxygen (O). The carbon and lead are consistent with ash from the combustion of aviation fuel, while the aluminum and oxygen were consistent materials from spark plugs in the form of aluminum oxide which is present in ceramics. Inspection of the ceramic insulators revealed spalling along the top edge of both, which is an indicator of exposure of high temperature of a period of time. A copy of the e-mail is contained in the NTSB public docket. Following inspection of the engine by FAA personnel, the airplane was recovered and with the permission of NTSB, the No. 2 cylinder was removed by an airframe and powerplant mechanic with inspection authorization for further analysis. The mechanic reported, "There was no indication of any problems with the cylinder, piston, rings - etc." None of the ring gaps were aligned. A copy of the statement from the mechanic and pictures of the cylinder are contained in the NTSB public docket. A pilot who last flew the airplane before the accident pilot stated that during his approximate 35 minute flight the day before, there were no issues with the airframe or engine with all systems working as normal. Review of the airplane maintenance records revealed the engine was last inspected in accordance with a 100-Hour inspection on January 4, 2013. The tachometer time at that time was recorded to be 3,066.8 hours, while the tachometer time at the time of the accident was recorded to be 3,163.3, or an elapsed time of 96.5 hours. A copy of the engine logbook entry for this inspection is contained in the NTSB public docket. The VA85 Airport is a privately owned airport that has one grass runway designated 18/36, which is 2,400 feet long and 100 feet wide. According to the airplane's Owner's Manual, the use of 5 degree of flaps is not specified for takeoff; however, the use of 10 degree of flaps is documented to shorten the ground run approximately 10 percent but this advantage is lost in the climb to a 50-foot obstacle. Review of the takeoff performance charts specify that when operating on a dry grass runway, to increase the distances for ground run and total to clear a 50 foot obstacle by 7 percent of the figure for the total to clear a 50 foot obstacle. Based on the provided weight at the time of the accident (2,104 pounds), the 15 knot headwind reported by the pilot, and the 7 percent adjustment for grass runway, the ground run distance was calculated to be 492 feet while the total distance to clear a 50 foot obstacle was calculated to be 914 feet. Because the performance chart does not specify how to adjust the distances for an upsloping runway, no determination could be made on the total distances.
The pilot's failure to abort the takeoff after recognizing that the airplane was not accelerating properly, which led to an aerodynamic stall. The reason for the lack of acceleration could not be determined because postaccident examinations did not reveal any anomalies that would have precluded normal operation.
Source: NTSB Aviation Accident Database
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