CEN21LA335

The airplane owner and the other pilot met each other at an aviation event just before the accident flight. After a short discussion, the two pilots decided to conduct a local flight in the accident airplane. After takeoff, while on the downwind leg of the traffic pattern, the right seat pilot (non-owner) asked to take the airplane’s controls from the owner (seated in the left seat), and a positive exchange of controls was accomplished. The right seat pilot then flew a low approach over a temporary grass runway with 40° of flaps extended. The right seat pilot did not intend to land; instead, he performed a go-around about 100 ft above the ground with full engine power and carburetor heat in the OFF position. The right seat pilot then attempted to retract the flaps, and he reported the flaps would not retract. The left seat pilot attempted to cycle the flap switch and was unsuccessful in retracting the flaps. Unable to maintain altitude, the right seat pilot performed an off airport landing to a corn field. The airplane impacted the corn field, flipped over, and came to rest inverted. The airplane sustained substantial damage to the engine firewall and engine mount. Postaccident examination of the airframe and engine, which included testing of the flap system, revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. A four-port universal serial bus (USB) power supply adapter was found plugged into a power port located just below the cockpit flap switch. It was undetermined if the adapter conflicted with the operation of the flap switch. Based on available evidence, a reason for the reported flap issue was not determined.

On July 24, 2021, about 1830 central daylight time, a Cessna 150F, N7893F, was substantially damaged when it was involved in an accident near Rock Falls, Illinois. The two pilots were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the airplane owner, he and the other pilot met each other at an aviation event just before the accident flight. After a short discussion, the two pilots decided to conduct a local flight in the accident airplane. The owner, who was seated in the left seat, stated that the airplane’s engine needed to be hand-propped due to a starter that “wasn’t very powerful.” After the engine start-up, the pilots monitored the airplane’s electrical system and performed an engine run-up with no issues noted. After takeoff, while on the downwind leg of the traffic pattern, the right seat pilot asked to take the airplane’s controls from the left seat pilot, and a positive exchange of controls was accomplished. The right seat pilot then flew a low approach over a temporary grass runway with 40° of flaps extended. The right seat pilot did not intend to land and performed a go-around about 100 ft above the ground with full engine power and carburetor heat in the OFF position. The right seat pilot then attempted to retract the flaps; however, the flaps would not retract. The left seat pilot attempted to cycle the flap switch and was unsuccessful in retracting the flaps. Unable to maintain altitude, the right seat pilot performed an off airport landing to a corn field. The airplane impacted the corn field, flipped over, and came to rest inverted. According to a Federal Aviation Administration (FAA) inspector, the airplane sustained substantial damage to the engine firewall and engine mount. The inspector also noted a four-port USB power supply adapter was plugged into a power port just below the flap switch (see figure 1). Figure 1. Instrument Panel (photograph provided by the FAA) A review of the airplane logbooks revealed that the airplane had been disassembled, inspected, and reassembled; all work was completed on July 1, 2014. Part of the aircraft reassembly included the replacement of the instrument panel and some aircraft wiring. The flap switch was relocated from its original position and was also changed to a new flap switch design. A circuit breaker had been installed in the flap wiring, which replaced the original fuse. A cigarette style power port was installed below the flap handle. The total tachometer time from the July 2014 maintenance to the accident was about 150 hours. Postaccident examination of the airplane was conducted by a FAA inspector and a representative of Textron Aviation. The examination revealed that the flaps were in the full-down or 40° extended position. The airplane battery was connected (disconnected for recovery purposes) and the master switch was turned on. The flap system was tested multiple times, flaps retracted and extended withcockpit flap switch, and no anomalies were noted with the function of the flap system. No visual abnormalities were noted during the examination of the flap wiring. The wiring in the wing was manipulated by hand during the flap extension and retraction cycles, and no problems were noted. The flap circuit breaker was pulled during a flap cycle, and the flap movement stopped. When the circuit breaker was reset, the flaps began to operate. At some point after the FAA’s initial examination of the airplane, the four-port USB power supply adapter had been removed from the power port and was located in the aft baggage area. According to the Cessna’s 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.” Multiple requests to obtain a completed National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident form and a statement from the right seat pilot were unsuccessful.