Cessna 172 N734FT accident near St. Johns, Arizona

Probable cause

The pilot's inadequate preflight planning before takeoff in the high density altitude conditions, which resulted in the airplane being unable to maintain sufficient airspeed to continue to climb.

NTSB analysis

The pilot reported that he initially attempted to take off, but the airplane was not accelerating fast enough and he aborted the takeoff. The pilot then decided to take off from a longer runway at the airport. When the airplane was about 100 ft above ground level, he observed that it was not continuing to climb. The pilot-rated passenger/owner stated that the stall warning horn sounded. The airplane began to lose altitude and subsequently collided with a stand of trees. The airplane came to rest inverted and sustained substantial damage to both wings, the forward fuselage, and the empennage. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation and that the airplane's weight was about 50 lbs less than its maximum gross takeoff weight. The pilot-rated passenger reported that he thought that the high density altitude was the cause of the accident.

The calculated density altitude was about 8,600 ft at the time of the accident. According to the Federal Aviation Administration Koch Chart, given the surrounding temperature and field elevation, the airplane would have likely experienced a 68% decrease in the normal climb rate. Thus, it is likely that the airplane did not have sufficient airspeed to climb in those conditions.

Text from the NTSB. Open the NTSB docket for WPR18LA262 for the full record.