Piper PA-28-140 N6834W accident near Prescott, Arizona

Probable cause

The pilot-in-command’s inadequate preflight planning for the high density altitude and relative humidity conditions and his failure to recognize the need to reject the takeoff, allowing the student pilot to execute an abnormally long takeoff roll and apply excessive nose-high control inputs, which resulted in rotation with inadequate climb performance and an inflight collision with terrain.

NTSB analysis

The private pilot, who was pilot-in-command (PIC) and seated in the left seat, and the student pilot, who owned the airplane and was seated in the right seat, had landed at the airport with the two passengers to refuel the airplane. The airport had a field elevation of 5,045 ft mean sea level (msl) and the density altitude was calculated to be 6,375 ft. The PIC calculated that the airplane’s weight after fueling was about 38 lbs under its maximum gross weight and within the center of gravity envelope.

The student pilot taxied the airplane for departure and reported that the engine run-up was normal. He subsequently requested a “short delay” from the air traffic controller to review the takeoff checklist with the PIC, including verifying the flap setting, rotation airspeed, and climb airspeed.

During the takeoff roll, the airplane used about 3,000 ft of runway before rotating. When the airplane was about 200 ft above ground level (agl), it stopped climbing, and the stall warning light illuminated. The student pilot said he had “every intent of us pulling on the yoke to maintain the climb” but that, after a few seconds of trying to gain airspeed by leveling the nose, the airplane would not maintain airspeed or gain altitude.

The PIC took control of the airplane to attempt to maximize airspeed and glide distance but stated that his forward visibility was limited due to the airplane’s nose-high attitude and that he was unable to see a nearby road that the student pilot had identified as suitable for landing; the student pilot took control of the airplane and directed it toward the road. During the landing sequence, the airplane collided with treetops and a tree branch before coming to rest at the side of the road.

Postaccident examination of the airplane and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. Using an external fuel source, the engine was run uneventfully throughout various power settings.

According to the airplane performance charts in the owner’s handbook (OH) for the airplane, based on the density altitude conditions at the time of takeoff, the calculated takeoff distance ground run for the airplane was about 1,600 ft. Although the student pilot had mistakenly calculated that the ground run would be “around 2,700 ft,” the student pilot continued the takeoff after the airplane’s ground roll exceeded that distance, and the PIC did not call for a rejected takeoff. The 7,619-ft runway would have provided ample distance to stop the airplane on the runway had a rejected takeoff been initiated, even at the erroneously calculated ground roll distance.

The excessive ground roll before rotation, the illumination of the stall warning light shortly after rotation, and the student pilot’s statement that his intention was to pull on the yoke to maintain the climb all provide evidence that the student pilot excessively raised the airplane’s nose during the takeoff roll and climb; the PIC did not intervene until after the stall warning light illuminated. The excessive nose-high attitude degraded the airplane’s takeoff roll and climb performance.

Further, the PIC stated that the student pilot reported a loss of engine rpm during the climb. The pretakeoff engine run-up (ground check) procedures in the OH for the airplane specified the use of carburetor heat to melt any ice that may have formed during taxiing. However, as noted earlier, after completing the run-up, the PIC and the student pilot delayed initiating the takeoff roll. Given this extended ground time after run-up, and based on the carburetor icing probability charts that indicated the conditions were conducive to the formation of serious carburetor icing at glide power, it is possible that carburetor icing formed, further degrading the airplane’s takeoff and climb performance.

Text from the NTSB. Open the NTSB docket for WPR23LA334 for the full record.