CEN17FA111 · Cessna 172S

The flight instructor and the commercial pilot receiving instruction were conducting a local training flight to practice aerodynamic spins. A review of air traffic control radar track data established that the airplane entered two aerodynamic spins during the flight. The first aerodynamic spin began at 10,300 ft mean sea level (msl), and the airplane descended about 1,000 ft before it recovered into a climb. The airplane then made a series of climbing turns until reaching 10,800 ft msl where it entered a second aerodynamic spin. The airplane did not recover from the second spin before it descended below available radar coverage at 6,800 ft msl (about 1,700 ft above the ground). Multiple witnesses reported seeing the airplane descending in a nose-down spin. One witness stated that the airplane completed about 5 turns in the spin before it descended behind a tree line into a reservoir.

The airplane's Pilot Operating Handbook specified that at least 1,000 ft of altitude loss should be expected for a one-turn spin and recovery and that a six-turn spin and recovery may require more than twice that altitude loss because the airplane can develop a rapid rate of rotation and a steep nose-down pitch attitude. A postaccident examination revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation during the flight. Additionally, the examination did not identify any foreign object debris that would have limited full movement of the flight controls during the flight, and the airplane's weight and balance were within the specified limits to conduct aerodynamic spins. It is likely that the pilots did not apply prompt and/or correct flight control inputs to adequately recover from the intentional aerodynamic spin.

Verbatim NTSB analysis and probable cause from the NTSB dataset