Aviation Accident Summaries

Aviation Accident Summary WPR11LA361

Perris, CA, USA

Aircraft #1

N6718X

BEECH 76

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.

Factual Information

On July 30, 2011, about 0825 Pacific daylight time, a Beech 76 (Duchess), N6718X, impacted terrain during initial climb seconds after takeoff from runway 15 at the Perris Valley Airport, Perris, California. Of the four occupants on board the airplane, the private pilot was seriously injured, one passenger received minor injuries, and two passengers were not injured. The airplane's fuselage and wings were deformed during the impact, and the airplane was substantially damaged. California Flight Center, Inc., Long Beach, California, operated the airplane and had rented it to the pilot for his personal flight. The flight was performed under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed. No flight plan was filed for the planned cross-country flight to Paso Robles, California. The flight was originating at the time of the crash. The pilot reported to the National Transportation Safety Board investigator that he performed a preflight inspection of the airplane and was familiar with the airplane's takeoff performance and runway distance requirements. According to the pilot, he loaded the airplane to near its maximum certificated gross weight, and he elected to depart from near the 5,100-foot-long runway's mid-field location. The pilot stated that he adhered to the prescribed procedures written in the airplane's check lists. During the engine run-up, no mechanical discrepancies were noted. Full engine power was attained, the brakes were released, and the takeoff roll commenced. However, prior to reaching the prescribed rotation airspeed, the airplane's nose pitched up, and the airplane became airborne. The pilot further reported that he continued attempting to maintain control of the airplane while in ground effect. The airplane climbed over one wingspan above the ground. When the left side cockpit door inadvertently opened, he was able to close it. Thereafter, 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. The winds at a nearby airport 6 miles away was from 330 degrees at 6 knots a the time of the accident. FAA inspectors from the Riverside, California, Flight Standards District Office responded to the accident site. The Chief Pilot for the operator also responded to assist in the recovery and removal of the aircraft from the site. 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 the system disclosed normal function. The FAA inspectors removed all the items from the baggage compartment and weighed them on a scale; the baggage compartment contents weighed 288 pounds. The baggage compartment structural limit is listed as 200 pounds in the airplane flight manual (AFM). Utilizing the aircraft empty weight and center of gravity listed in the weight and balance section of the AFM, the actual weights of the occupants, the fuel load found on the airplane, and the weight of the baggage compartment contents, the inspectors determined that the aircraft gross weight at the accident site was 4,173.41 pounds with a center of gravity at 117.9 inches aft of the datum. The AFM and the FAA approved Type Certificate Data sheet lists the maximum allowable gross weight as 3,900 pounds with an aft center of gravity limit at 117.5 inches.

Probable Cause and Findings

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.

 

Source: NTSB Aviation Accident Database

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