ERA11LA240

The pilot’s failure to maintain adequate airspeed during the initial climb, which resulted in an aerodynamic stall and subsequent impact with the ground.

The twin-engine airplane was scheduled for a routine night cargo flight. Witnesses and radar data described the airplane accelerating down the runway to a maximum ground speed of 97 knots, then entering an aggressive climb before leveling and pitching down. The airplane subsequently impacted a parallel taxiway with its landing gear retracted. Slash marks observed on the taxiway pavement, as well as rotation signatures observed on the remaining propeller blades, indicated that both engines were operating at impact. Additionally, postaccident examination of the wreckage revealed no evidence of any preimpact mechanical failures or malfunctions of the airframe or either engine. The as-found position of the cargo placed the airplane within the normal weight and balance envelope, with no evidence of a cargo-shift having occurred, and the as-found position of the elevator trim jackscrew was consistent with a neutral pitch trim setting. According to the airframe manufacturer's prescribed takeoff procedure, the pilot was to accelerate the airplane to an airspeed of 85 knots, increase the pitch to a climb angle that would allow the airplane to accelerate past 96 knots, and retract the landing gear before accelerating past 128 knots. Given the loading and environmental conditions that existed on the night of the accident, the airplane's calculated climb performance should have been 1,800 feet per minute. Applying the prevailing wind conditions about time of the accident to the airplane's radar-observed ground speed during the takeoff revealed a maximum estimated airspeed of 111 knots, and the airplane's maximum calculated climb rate briefly exceeded 3,000 feet per minute. The airplane then leveled for a brief time, decelerated, and began descending, a profile that suggested that the airplane likely entered an aerodynamic stall during the initial climb.

HISTORY OF FLIGHT On April 11, 2011, at 2127 eastern daylight time, a Piper PA-31-350, N3547C, operated by Airnet Systems, Inc. as U.S. Check flight 901, was substantially damaged when it impacted a taxiway after takeoff from Richmond International Airport (RIC), Richmond, Virginia. The certificated commercial pilot was seriously injured. Night visual meteorological conditions prevailed, and an instrument flight rules (IFR) flight plan was filed for the flight, which was destined for Charlotte/Douglas International Airport (CLT), Charlotte, North Carolina. The non-scheduled cargo flight was conducted under the provisions of 14 Code of Federal Regulations Part 135. Two airport firefighters observed the airplane during its attempted departure from runway 20, and during separate interviews, recounted a similar series of events. Both of the firefighters were standing on the airport fire station ramp, located about 1,000 feet east of the intersection between runway 20 and taxiway C. The firefighters reported that the airplane began the takeoff roll normally, but became alarmed as the airplane became airborne before reaching taxiway C, and its pitch increased to an extreme angle. At its maximum pitch angle, the airplane was climbing near vertically, and one of the firefighters remarked that the airplane appeared similar in attitude to an airplane at an air show. He found the airplane's pitch attitude so unusual, he began running toward the airport fire truck with the intent of responding to a crash. The other firefighter continued to watch as the airplane climbed to an estimated altitude about 300 feet above the ground, before it pitched down and briefly leveled. The airplane then pitched down further, and briefly leveled again. The second firefighter then also realized that the airplane would crash, and began preparing to respond. One of the firefighters remarked that during the initial portion of the takeoff, the airplane's engines sounded normal, smooth, and continuous. The sound then changed as the airplane pitched vertically, giving him the impressions that the engines had "throttled up." He also remarked that the airplane's pitch upward began just about the time the airplane crossed taxiway C, which was located about 2,300 feet from the runway 20 threshold. According to radar and voice communication data provided by the Federal Aviation Administration (FAA), a radar target correlated to the accident airplane's assigned transponder code began moving from the northern ramp area at RIC toward runway 20 at 2127. About that time the pilot contacted the air traffic control tower and was cleared for takeoff. About 2128:10, the airplane began its takeoff roll from runway 20. Measurement and calculation of the airplane's radar-derived position showed that about 9 seconds later, the airplane had traveled about 950 feet down the runway and reached a maximum groundspeed of about 97 knots. The airplane's reported altitude did not change for another 9 seconds, at which time the altitude increased by 200 feet, about the time the airplane crossed the point where runway 20 intersected taxiway C, and about 1,900 feet from the point where the airplane began the takeoff roll. About 4 seconds later, at 0128:32, the airplane's altitude had increased by another 300 feet, and the calculated groundspeed had decreased to 44 knots. The airplane's calculated climb rate during this timeframe was 3,920 feet per minute. During the next 4 seconds the airplane only traveled 103 feet, and its reported altitude remained constant. The airplane then descended 200 feet during the following 4 seconds, and traveled 270 feet across the ground. No further transponder-correlated radar targets were recorded; however an uncorrelated radar target recorded 5 seconds later placed the airplane 325 feet from the previous correlated radar target and about 200 feet from the initial impact point. The pilot was seriously injured during the accident sequence and did not regain consciousness until about 1 month after the accident. During a telephone interview conducted about 4 months after the accident, the pilot recalled the sequence of events that transpired immediately prior to and during the accident flight. After performing a preflight inspection of the airplane, the pilot confirmed the airplane's weight and balance as well as the fuel load. The inboard fuel tanks were full and the outboard fuel tanks were about 1/4 full. The pilot then started the engines and performed a run-up check, noting no anomalies. He then taxied the airplane to the fixed base operator where he loaded the cargo. Once the airplane was loaded, he again started the engines, obtained an IFR clearance, and taxied for departure. After taxiing onto runway 20, the pilot held the brakes and increased engine power to 2,000 rpm, after which he released the brakes and continued increasing the engine power to full. During the takeoff run he rotated the nose upward within the first 1,500 feet of runway, and around 65 knots indicated airspeed. He then pitched the airplane for the climb out airspeed, the blue line on the airspeed indicator. He then tapped the brakes and retracted the landing gear. He also stated that customarily he would retract the landing gear about 3 to 5 seconds after rotation, at an altitude about 200 feet above the ground, and that the landing gear retraction cycle took about 5 seconds. Once the landing gear had retracted, the pilot stated that he perceived a yawing sensation, with the nose of the airplane gradually pulling to the left, and noted a change in engine sound. He did not note any loud sounds or banging, but did notice a definite difference. He then looked at the manifold pressure gauge and noted that the left engine indicated 0 inches of manifold pressure and the needle was "fluttering." He responded by reducing the throttles of both engines to idle as he wanted to avoid a roll induced when the airplane's airspeed was degraded below the minimum single engine controllable airspeed. The pilot reported that he did not have time to extend the landing gear before the conclusion of the event, and could not recall any of the events that transpired after he closed the engines' throttles. PERSONNEL INFORMATION The pilot held a commercial pilot certificate with ratings for airplane singe and multiengine land, and instrument airplane. He also held a flight instructor certificate with ratings for airplane single and multiengine, and instrument airplane. His most recent FAA first-class medical certificate was issued on January 1, 2011 with the limitation, "must wear corrective lenses." According to the operator, the pilot had accumulated 1,946 total hours of flight experience, 88 of which had been accrued in the 90 days preceding the accident. The pilot had accumulated 31 total hours of flight experience in the accident airplane make and model, all of which were accrued in the 90 days preceding the accident. The pilot began training with the operator on January 27, 2011, and was hired on February 11, 2011. Between February 8 and 10, the pilot completed 4.9 hours of initial flight training in the Beech BE-58, and completed transition training in the accident airplane make and model on February 17, 2011 after 2.1 hours of training. AIRCRAFT INFORMATION The accident airplane was manufactured in 1979, and was powered by two Lycoming (L)TIO-540-J2BD engines driving counter-rotating propellers. The airplane's originally certificated maximum takeoff weight was 7,000 pounds; however the airplane had been modified by a supplemental type certificate that increased the maximum takeoff weight to 7,368 pounds. According to the operator, at the time of the accident the airplane was loaded to a gross weight of 6,700 pounds. The airplane's most recent annual inspection was completed on October 13, 2010, and on that date the airplane had accumulated 17,265 total flight hours. The airplane had ac