Cessna 172 N3090U accident near Waxhaw, North Carolina

Probable cause

The pilot’s failure to abort the takeoff in sufficient time to stop the airplane on the runway remaining. Contributing to the accident was the lack of airplane takeoff performance due to the pilot’s failure to assure that the carburetor heat control was in the off position and the elevated density altitude.

NTSB analysis

The accident occurred while the flight was taking off during an aviation youth camp. The pilot reported the airplane became airborne and climbed in ground effect to an altitude of about 50 ft above ground level (agl). He stated the airplane climb rate seemed sluggish, so he transitioned the airspeed from the best rate of climb to the best angle of climb, but he still did not get the climb performance he expected. The pilot momentarily reduced the power to land, then realized there were trees and a fence off the end of the runway, so he added power to land on a lawn just beyond the airport. The pilot applied rudder during the landing roll to avoid trees and in doing so, the airplane nosed over and came to rest nose down, leaning up against a tree. During the impact sequence, the airplane was substantially damaged. The pilot and the two passengers received minor injuries.

According to witnesses, during the takeoff the angle of climb was much less than expected and the airplane never climbed above 10 to 20 ft above the runway. One witness reported the engine sounded sluggish. Several of the witnesses reported seeing the airplane bank to the right before they lost sight of it. One stated the airplane pitched down and rolled to the right, then pitched up and rolled to the left before impact.

Review of weight and balance information revealed that the airplane was within the weight and balance envelope during the flight. Examination of the wreckage did not reveal evidence of any preimpact failures or malfunctions that would have precluded normal operation. However, the carburetor heat control knob was found to not be fully closed and the carburetor heat door was found to be open.

The airplane’s performance charts indicated that the airplane would need a 950-ft ground roll for takeoff and 1,680 ft to clear a 50-ft obstacle. The takeoff was being conducted from a runway that was 3,309 ft long. There were two takeoff abort points designated in the briefing for the event, one for each runway. The pilot confused the abort points and was using the abort point designated for the opposite direction runway. The abort point for he should have used was 830 ft from the beginning of the runway, while the abort point he actually used was 1,300 ft from the beginning of the runway. This confusion regarding abort points reduced the amount of available runway remaining for the pilot to stop the airplane once he realized the airplane was not going to clear the trees at the end of the runway.

Based on the available evidence, a loss of engine performance likely occurred during the takeoff because the carburetor heat control knob was not fully closed. This loss of power would also have been compounded by the elevated density altitude, which also would have decreased the airplane’s takeoff performance. The pilot’s delay in aborting the takeoff left the airplane airborne but with insufficient distance and performance to clear the tree line.

Text from the NTSB. Open the NTSB docket for ERA21LA313 for the full record.