Cessna 172 N90559 accident near Branchville, New Jersey

Probable cause

The flight instructor’s failure to recover from a steep spiral turn during an instructional flight.

NTSB analysis

While on an instructional flight, control of the airplane was lost during a flight maneuver, and the airplane impacted the terrain in a heavily wooded area. Data recovered from the Garmin G1000 integrated flight instrument system revealed that the airplane climbed to a cruise altitude of about 6,400 ft and remained on a northwesterly heading for the first 17 minutes of the flight. The airplane’s airspeed began to decrease due to an engine power reduction from 2,400 rpm to 1,300 rpm. The airplane began to pitch nose up, ultimately reaching a maximum pitch attitude of about 37° as the airspeed slowed to 28 knots indicated. The airplane reached a left-wing-down bank angle of 102° and a nose-down pitch attitude of 79°. The G1000 recorded the airplane’s descent rate at over 8,000 ft/minute 3 seconds later. A surveillance security video showed the airplane in a very steep spiral turn that continued until the airplane was out of view of the camera. Based on the data recovered from the G1000, the reduction of power was intentional, and the aerodynamic stall was induced. The flight instructor’s logbook and receipts from previous flights show the flight instructor and private pilot had practiced steep spiral turns on several occasions.

All the major airplane components were located at the accident site. Examination of the airplane and the engine did not reveal any anomalies with the flight controls that would have precluded normal operation.

Although toxicological testing of the flight instructor’s blood was positive for THC and the THC metabolite THC-COOH, given the circumstances of this accident and the low concentration found in his blood, it is unlikely that the flight instructor’s performance was impaired by THC at the time of the accident.

Text from the NTSB. Open the NTSB docket for ERA22FA058 for the full record.