Aviation Accident Summaries

Aviation Accident Summary CEN15LA183

Gordonville, TX, USA

Aircraft #1

N80462

BEECH 35

Analysis

**This report was modified on August 7, 2020. Please see the docket for this accident to view the original report.** The commercial pilot and three passengers were departing in the single-engine airplane from a 3,000-ft-long grass runway. The pilot reported that he thought that the windsock showed light and variable winds, but a nearby airport reported gusting wind conditions about the time of the accident.  He considered taking off downhill toward a lake, but because of the possibility of a tailwind after passing the tree line, he chose to do a soft field takeoff uphill. The airplane lifted off at an indicated airspeed of 80 mph. As it neared the departure end of the runway, the pilot noticed that the airplane was not climbing as expected, the indicated airspeed seemed unreliable, and the controls felt mushy and near stall speed. Witnesses stated that the airplane traveled about halfway down the runway before it became airborne. One witness stated that he didn't think the engine speed was right and that the airplane was gaining altitude slowly. The other witness reported that the airplane wasn't gaining any altitude and that the engine sounded "strong," and did not cut out.  The airplane collided with trees and a building just beyond the runway before impacting terrain.  An examination of the airplane did not reveal any pre-impact abnormalities. Given the pilot's reported weight and the weight of the 28 gallons of fuel that the pilot reported were onboard, the airplane had a remaining useful load of 379 lbs to account for the 3 other passengers. Therefore, it is likely that the airplane was operating at or near its maximum gross weight at the time of the accident. With the additional factors of an upsloping, grass runway, the airplane's performance would have been degraded and the takeoff distance required would likely have been significantly increased. Although the pilot's operating handbook for the airplane did not contain information about takeoff performance from unpaved runways, Federal Aviation Administration (FAA) guidance states that any surface that is not hard and smooth increases the ground roll during takeoff due to the inability of the tires to roll smoothly along the runway. FAA guidance also states that the effect of an airplane's gross weight on takeoff distance is significant. Increased gross weight produces several effects on takeoff performance, including higher lift-off speed, greater mass to accelerate, and an increased retarding force (drag and ground friction). According to the airplane's takeoff distance chart, at its maximum gross weight and the atmospheric conditions at the time of the accident, the airplane would have required a ground roll of about 800 ft and a takeoff distance of about 1,400 ft to clear a 50-ft obstacle at the end of the runway. Additionally, the density altitude was about 2,249 feet. Although the exact point of rotation from the runway could not be determined, witnesses reported the airplane lifted off after traveling about 1,500 ft—much longer than the ground roll estimate in the airplane's takeoff distance chart. Even with the extended ground roll, the airplane should have been capable of climbing well above the 40 to 80 ft trees at the end of the runway in the 1,500 ft remaining after liftoff if it had been within its maximum gross weight limits. It is possible that, as the airplane approached the tree line with no margin for error in altitude, the wind gust reported by the pilot could have affected the airplane's ability to maneuver when it was so close to the trees, resulting in the impact. Ultimately, however, the pilot's decision to takeoff without accounting for the effect of the runway condition and the airplane's high gross weight and high density altitude on takeoff performance resulted in a long takeoff ground roll, reduced climb capability, and impact with trees at the end of the runway in gusting wind conditions.

Factual Information

On March 29, 2015, about 1600 central daylight time, a Beech 35 single-engine airplane, N80462, impacted terrain, after departing the Cedar Mills Airport (3T0), Gordonville, Texas. The pilot and one passenger were seriously injured, and two passengers received minor injuries. The airplane sustained substantial damage. The airplane was registered to and operated by a private individual. Day visual meteorological conditions prevailed at the time of the accident and a flight plan had not been filed for the 14 Code of Federal Regulations Part 91 personal cross-country flight which was destined for the Tyler Pounds Regional Airport (TYR), Tyler, Texas. The pilot reported that he performed a soft field takeoff from the turf runway, and the airplane lifted off at an indicated airspeed of 80 mph. As the airplane neared the departure end of the runway, the pilot noticed the airplane was not climbing as expected, the indicated airspeed seemed unreliable, and the controls felt mushy and near stall speed. The airplane impacted trees and the roof of an unoccupied home. The airplane then impacted terrain, about 50 ft from the house and came to rest upright after impacting two propane storage tanks. There was no release of propane and there was no postimpact fire at the main wreckage. Two witnesses observed the airplane depart from the runway. They stated that the airplane traveled quite a distance, or halfway down the runway before it became airborne. They added the right wing dropped, with one witness stating that he thought the airplane, "was going to crash right there". The witness stated he didn't think the engine speed was right and the airplane was slowly gaining altitude. The other witness reported that the airplane wasn't gaining any altitude and the engine sounded "strong" and did not cut out. In a post-accident interview, the pilot stated that that it took longer than expected to get airborne because the ground was soft, but the engine was developing full power. Adding that he thought that a gust of wind hit the airplane, causing the right wing to dip and lose airspeed. He added that the windsock showed light and variable winds. The runway was lined with thick trees on both sides. He added that he considered doing a downhill takeoff toward the lake, but because of the possibility of a tail wind after passing tree line, he chose to do a soft field takeoff in the other direction. Additionally, the pilot reported that he intended to request flight-following services from air traffic control once airborne. The engine and airframe were examined by an inspector from the Federal Aviation Administration (FAA) and technical representatives from the engine and airframe manufacturers. The exam noted that the landing gear was in the down position and the flap actuator corresponded to flaps up (retracted) position. The constant speed, two-bladed propeller remained attached to the crankshaft. One blade was twisted and bent rearward beginning about 8 inches from the hub. The other blade had chordwise scratching with a portion of the blade tip broken off. The engine received thermal and impact damage; however, no preimpact abnormalities were noted with the engine or airframe. A review of aircraft maintenance records revealed the last annual inspection was conducted on November 21, 2014. The last weight and balance sheet was completed on June 18, 2013, with an airplane empty weight of 1,765 lbs. The maximum gross weight of the airplane is 2,500 lbs. Using the pilot's listed weight and 28 gallons of fuel on-board, the remaining useful load for the remaining three passengers and any cargo would be about 379 lbs. The automated weather reporting station located about 10 miles southeast of the accident site recorded wind from 210 degrees at 9 knots, gusting to 15 knots. Based upon weather conditions near the accident site, the density altitude was about 2,249 ft. 3T0's runway 7/25, is described as a turf/grass runway 3,000 ft long by 60 ft wide. Runway 7/25 is surrounded by trees on three sides, and a lake on the departure end of runway 7. The chart supplement notes: 40 ft and 80 ft trees north and south of runway 25's centerline. According to the airplane's takeoff distance chart, at its maximum gross weight and the atmospheric conditions at the time of the accident, the airplane would have required a ground roll of about 800 ft and a takeoff distance of about 1,400 ft to accelerate to a safe takeoff speed and clear a 50-ft obstacle at the end of the runway.

Probable Cause and Findings

The pilot's decision to depart from an upsloping, soft grass runway at or near the airplane's maximum gross weight and with a high density altitude, which increased the airplane's ground roll and placed the airplane in close proximity to trees during the initial climb, and the pilot's subsequent inability to adequately compensate for gusting wind conditions, which resulted in a stall/mush and impact with trees and terrain during takeoff.

 

Source: NTSB Aviation Accident Database

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