What happened
On July 28, 2017, at approximately 23:01 UTC, a Diamond DA20, registration TF-KFG, was performing landing training at Keflavík Airport. The flight, which included a flight instructor and a student, had completed several touch-and-go landings and one approach before attempting a final landing on runway 01.
During the landing approach, the instructor observed that the student was performing a late flare. To assist, the instructor applied back pressure on the elevator, which caused the aircraft's airspeed to decrease. When the student queried whether a go-around was necessary, the instructor initiated the maneuver. Upon applying full power, the aircraft experienced a significant leftward yaw. The instructor attempted to correct the heading using the rudder, but the aircraft continued to drift left of the runway centerline.
In an attempt to regain altitude and utilize ground effect, the instructor retracted the flaps from landing to takeoff configuration. However, the aircraft failed to maintain sufficient altitude, drifted off the runway, and traveled across taxiway E-2, eventually coming to a stop at the western edge of the taxiway. There were no injuries to the occupants, though the aircraft sustained minor damage.
The investigation
The RNSA investigation focused on the sequence of events during the missed approach and the flight crew's adherence to standard operating procedures (SOP). The investigation established that the instructor had recently resumed flight instruction after a hiatus.
The investigation examined the aircraft's maintenance history, finding that the 100-hour inspection had been completed seven days prior to the accident and no mechanical failures were identified. The investigators also reviewed the flight school's SOPs, noting that while the instructor attempted to take control, the formal verbal exchange for transferring control ("My controls" / "Your controls") was not properly executed as required by the school's procedures.
Findings
- The aircraft's leftward deviation during the go-around was likely caused by a combination of P-factor, torque, spiraling slipstream, and gyroscopic effects acting on the aircraft at low airspeed.
- The instructor retracted the flaps from landing to takeoff configuration while the aircraft was at an insufficient airspeed to maintain flight.
- The instructor's intervention to assist the student's flare likely contributed to the loss of airspeed prior to the go-around attempt.