Luray, VA, USA
N738CD
CESSNA 172
The private pilot/owner used a checklist to conduct a preflight inspection of the airplane and did not note any anomalies. She started the engine, taxied to the fuel dock, and filled both fuel tanks. Her inspection of fuel samples from the two wing drains and the gascolator did not reveal any contaminants. After she conducted the engine run-up she determined that everything was normal with the airplane, then "applied full power" and "rotated [about] 50-52" knots. However, the airplane "did not want to climb," and she reconfirmed that the engine indications were appropriate and that the flaps were retracted. She aborted the takeoff and steered the airplane off the side of the runway in order to avoid the drop-off at the end of the runway. A pilot-rated witness reported that he did not observe an engine run-up and that the airplane became airborne two separate times before the takeoff was aborted. The airplane struck a fence, descended a grassy embankment, and came to rest. No mechanical deficiencies or other anomalies that could account for the accident were detected with the airplane. The airplane manufacturer's normal takeoff procedure specifies that the pilot should lift the nosewheel at 55 knots and climb out at a speed between 70 and 80 knots. The aerodynamic phenomenon known as ground effect likely enabled the airplane to become airborne at a speed less than the manufacturer's specified liftoff speed.
HISTORY OF FLIGHT On November 8, 2009, about 1040 eastern standard time, a Cessna 172N, N738CD, was substantially damaged during an aborted takeoff from runway 22 at Luray Caverns Airport (W45), Luray, Virginia. The private pilot/owner and her passenger were not injured. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the flight. According to the pilot, she conducted a preflight inspection using a checklist, with no anomalies noted. She then pulled the airplane from its hangar, started the engine, and taxied to the fuel dock, where she filled both fuel tanks. She sampled fuel from the two wing drains and the gascolator to check for water or other contaminants, and none were noted. She and the passenger, her son, then boarded the airplane. The pilot stated that she then started the airplane, checked via radio for airport advisory and traffic information, and "taxied to the end of runway 22 and did the run-up." The flaps were set to the retracted position for the takeoff. She determined that "everything was normal" with the airplane, "applied full power" and "rotated [about] 50-52" knots. She "sensed something was wrong," and when asked to elaborate, she stated that the airplane "did not want to climb." In an attempt to diagnose the problem, the pilot reconfirmed that the engine indications were appropriate, and that the flaps were retracted. She then "cut the power" and "landed back on the [runway] centerline." She recognized that she would not be able to stop the airplane on the remaining runway, and in order to avoid the drop-off at the end of the runway, she steered the airplane onto the grass to the right of the runway. The airplane struck a fence, descended a grassy embankment, and came to rest. The passenger's account mirrored the pilot's account. According to an airline transport pilot-rated witness, he was standing outside at the fuel dock approximately mid-field, while the airport manager was fueling his airplane. The witness was facing the runway, watching the Cessna, and was "surprised to hear no run-up." He stated that the airplane taxied onto the runway and headed for the approach end of runway 22 for its departure. The airplane initiated its takeoff roll and became airborne "just short of the windsock," which was also approximately midfield. The witness stated that this seemed "normal" to him. The airplane "climbed 8-10 feet," but then "settled" back onto the runway on all three landing gear. The airplane immediately became airborne again, and at this point the witness believed that the engine "still sounded normal." However, the airplane only climbed to approximately 4 feet above the runway, and it then descended, and touched down nose-gear first on the runway. The witness saw the airplane drift to the right, and heard the power "come off" as the airplane departed the paved runway surface. The witness believed that the pilot would not be able to stop safely, and then he and the airport manager began to run in the direction of the airplane. By the time they arrived at the accident location, the pilot and passenger had exited the airplane. The witness stated that when he checked the cockpit, the "mag[neto]s, electrics, and fuel were still on." PERSONNEL INFORMATION Federal Aviation Administration (FAA) records indicated that the pilot held a private certificate with an airplane single engine land rating. Her most recent FAA third-class medical certificate was issued in January 2009. The pilot reported 299 total hours of flight experience, which included 278 hours in the accident airplane make and model. She reported 87 hours as pilot in command, all of which was in the accident airplane make and model. She reported 4 hours of flight experience in the 90 days preceding the accident, all of which was in the accident airplane make and model. She reported that she had no flight experience in the 60 days preceding the accident. Her most recent flight review was completed in October 2008. AIRCRAFT INFORMATION FAA records indicated that the airplane was manufactured in 1977, and that it was equipped with a Lycoming O-320 series piston engine. The airplane was co-registered to the pilot and another individual in November 2005. According to the FAA inspector, the airplane's most recent annual inspection was completed in December 2008, at which time the airplane had 4,226.4 total hours in service. At the time of the accident, the airplane had accumulated 4,253.6 total hours in service. The airplane manufacturer's pilots operating handbook (POH) stated that "normal and short field takeoffs are performed with flaps up," and that 10 degrees of flaps were to be used for soft-field takeoffs, or takeoffs with a minimum ground roll. The POH "Normal Procedures" stated that for a normal takeoff, the procedure was to use the elevator control to lift the nose wheel at 55 knots, and climb out at a speed between 70 and 80 knots. The POH specified a climb speed of 59 knots for obstacle clearance takeoffs. The pilot estimated that the airplane gross weight at the time of the accident was 1,945 pounds, and within the allowable center of gravity limits. Performance tables in the POH indicated that for the ambient atmospheric conditions, the distance to clear a 50 foot obstacle was approximately 1,600 feet at the airplane's maximum certificated takeoff weight of 2,300 pounds, and approximately 1,300 feet at a gross weight of 2,100 pounds. METEOROLOGICAL INFORMATION According to the FAA inspector, the 1030 recorded weather observation at W45 reported winds from 220 degrees at 3 knots, 10 miles visibility, temperature 66 degrees F (approximately 19 degrees C), dew point 42 degrees F (approximately 6 degrees C). The 1040 recorded weather information at an airport 20 miles east-southeast of W45 reported clear skies, and an altimeter setting of 30.29 inches of mercury. AIRPORT INFORMATION FAA records indicated that W45 was equipped with a single asphalt runway, designated 4-22, that measured 3,125 feet by 75 feet. Airport elevation was listed as 902 feet above mean sea level. The airport had two ramp areas, one located towards the north end on the east side of the runway, and one approximately mid-field, also on the east side of the runway. The hangars were located between the two ramps, just south of the north ramp. The fuel dock was located on the midfield ramp, and the windsock was across the runway from this ramp. The airport was not equipped with a parallel taxiway, which required pilots to taxi on the runway when they needed to transit between the two ramps, and to back-taxi on the runway before takeoff or after landing. The airport was not equipped with any turn-around or run-up areas at either end of the runway. WRECKAGE AND IMPACT INFORMATION According to information provided by the FAA inspector who responded to the accident scene, the airplane came to rest approximately 575 feet from the point where it departed the paved surface. The airplane remained upright, facing approximately west. The right wing and nose landing gear incurred substantial impact damage, and there was no fire. The wing flaps were found extended approximately 10 degrees, but the cockpit flap handle was in the position that corresponded to flaps retracted. The FAA inspector established control continuity for the elevator and rudder, but movement of either yoke did not result in corresponding aileron movement. The inspector noted that roll inputs to the yoke did result in noises in the wing. The pitch trim indicator in the cockpit was in the takeoff range. One propeller blade was bent aft, and one appeared undamaged. The inspector obtained a fuel sample from the gascolator, and it appeared clear, with no contaminants. No evidence of any pre-accident mechanical failures or malfunctions was detected with the airplane. ADDITIONAL INFORMATION Ground Effect According to the Airplane Flying Handbook (FAA-H-8083-3A) "ground effect" was defined as "a condition of improved performance encountered when an airplane is operating very close to the ground. When an airplane's wing is under the influence of ground effect, there is a reduction in upwash, downwash, and wingtip vortices. As a result of the reduced wingtip vortices, induced drag is reduced." The "Pilots Handbook of Aeronautical Knowledge" (FAA-H-8083-25) provided the following information regarding ground effect. "It is possible to fly an airplane just clear of the ground (or water) at a slightly slower airspeed than that required to sustain level flight" further from the ground. When an airplane in flight gets within several feet from the ground surface, a change occurs in the three dimensional flow pattern around the airplane." The aerodynamic interference is referred to as "ground effect," and the primary result is a significant drag reduction. According to the Handbook, an airplane leaving ground effect after takeoff will require an increased angle of attack to maintain the same lift coefficient, and will experience increased drag, increased thrust required, increased nose-up pitching moment, and decreased pitch stability. The Handbook cautioned that "these general effects should point out the possible danger in attempting takeoff prior to achieving the recommended takeoff speed. Due to the reduced drag in ground effect, the airplane may seem capable of takeoff well below the recommended speed. However, as the airplane rises out of ground effect with a deficiency of speed, the greater induced drag may result in very marginal initial climb performance...The airplane may become airborne initially with a deficiency of speed, and then settle back to the runway. It is important that no attempt be made to force the airplane to become airborne with a deficiency of speed; the recommended takeoff speed is necessary to provide adequate initial climb performance."
The pilot's premature rotation and liftoff and her subsequent failure to recognize and correct for the influence of ground effect on the airplane's takeoff performance.
Source: NTSB Aviation Accident Database
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