Beech 76 N6718X accident near Perris, California

Probable cause

The pilot’s failure to maintain airplane control and the resulting encounter with an aerodynamic stall. Also causal were the pilot’s inadequate preflight planning and preflight inspection, his failure to ensure the pitch trim was positioned correctly for takeoff, his decision to operate the airplane over maximum allowable gross weight, and his attempt to operate the airplane with a center of gravity aft of the rear CG limit.

NTSB analysis

According to the pilot, he loaded the airplane to near its maximum certificated gross weight before departing from near the 5,100-foot-long runway's midfield location. The pilot selected runway 15, which had a 6-knot tailwind component at the time of the attempted takeoff. During the engine run-up, no mechanical discrepancies were noted. The engine attained full power before the pilot released the brakes to commence the takeoff roll. Prior to reaching the prescribed rotation airspeed, the airplane's nose pitched up and the airplane became airborne. The pilot reported that he continued attempting to maintain control of the airplane while in ground effect. The airplane then climbed above ground effect, and the left cockpit door inadvertently opened. Just as the pilot closed the door, the airplane stalled, impacted an estimated 6-foot high dirt berm, and crashed into an open field about 1,000 feet south of the runway's departure end. During the postaccident examination, about 40 gallons of fuel were found in each of the two wing tanks, for a total of 80 gallons onboard at the time of the accident. The elevator trim tab was found in the full nose-up position, and examination of that system disclosed normal function. All of the items from the baggage compartment were removed and weighed on a scale; the baggage compartment contents weighed 288 pounds, which is 88 pounds above the compartment limit. Using the airplane’s empty weight and center of gravity listed in the weight and balance section of the airplane flight manual (AFM), the actual weights of the occupants, the fuel load found on the airplane, and the weight of the baggage compartment contents, the investigation determined that the airplane’s gross weight at the accident site was 4,173.41 pounds, with a center of gravity (CG) 117.9 inches aft of the datum. The AFM and the FAA-approved Type Certificate Data sheet list the maximum allowable gross weight as 3,900 pounds with an aft CG limit at 117.5 inches. Airplanes at or aft of the rear CG limit are very sensitive in pitch control, and may even be at or near a dynamically unstable flight regime in terms of pitch handling and dampening characteristics. Accordingly, the airplane would have been especially sensitive to the full nose-up trim tab adjustment. Additionally, stall speeds increase as gross weight increases, so in the takeoff condition the airplane would have stalled at a higher airspeed, sooner than the pilot would have normally experienced and expected.

Text from the NTSB. Open the NTSB docket for WPR11LA361 for the full record.