Incident Overview
On July 24, 2021, at approximately 1830 central daylight time, a Cessna 150F, registration N7893F, sustained substantial damage during an accident near Rock Falls, Illinois. The two occupants, both pilots, were not injured. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Flight Sequence
The airplane owner met the other pilot at an aviation event earlier that day. After a brief discussion, they decided to conduct a local flight in the owner's airplane. The owner, seated in the left seat, reported that the airplane's engine required hand-propping because the starter "wasn't very powerful." Following engine start, the pilots checked the electrical system and performed an engine run-up without issues.
After takeoff, during the downwind leg of the traffic pattern, the right-seat pilot requested control of the airplane from the left-seat pilot, and a positive exchange of controls was executed. The right-seat pilot then flew a low approach over a temporary grass runway with 40° of flaps extended. The pilot did not intend to land and initiated a go-around at about 100 feet above ground level with full engine power and carburetor heat off. Attempting to retract the flaps, the right-seat pilot found them unresponsive. The left-seat pilot also tried to cycle the flap switch without success. Unable to maintain altitude, the right-seat pilot performed an off-airport landing in a corn field. The airplane impacted the field, flipped over, and came to rest inverted.
Post-Accident Examination
A Federal Aviation Administration (FAA) inspector noted substantial damage to the engine firewall and engine mount. A four-port USB power supply adapter was observed plugged into a power port just below the flap switch. Review of the aircraft logbooks indicated that the airplane had been disassembled, inspected, and reassembled on July 1, 2014, which included replacement of the instrument panel and some wiring. The flap switch was relocated and changed to a new design; a circuit breaker replaced the original fuse in the flap wiring. A cigarette-style power port was installed below the flap handle. Total tachometer time from that maintenance to the accident was about 150 hours.
Post-accident examination by an FAA inspector and a Textron Aviation representative found the flaps in the full-down (40°) position. With the battery connected and master switch on, the flap system was tested multiple times; the flaps retracted and extended normally using the cockpit switch. No wiring abnormalities were observed. Manipulating the wiring in the wing during flap cycles caused no issues. When the flap circuit breaker was pulled, flap movement stopped; resetting it restored operation. At some point after initial FAA examination, the USB adapter had been removed from the power port and was found in the aft baggage area.
Relevant Manual Guidance
According to the Cessna Owner's Manual, Section 2, Flap Settings: "Normal and obstacle clearance take-offs are performed with flaps up…flap deflections of 30° and 40° are not recommended at any time for take-off…In a balked landing (go-around) climb, the wing flap setting should be reduced to 20° immediately after full power is applied. Upon reaching a safe airspeed, the flaps should be slowly retracted to the full up position."
Additional Information
Multiple attempts to obtain a completed NTSB Pilot/Operator Aircraft Accident/Incident form and a statement from the right-seat pilot were unsuccessful.