Training

An engineering investigation found no fault with the aircraft that might have caused the accident. The investigation concluded that the most probable cause was an inadvertent retraction of the landing gear whilst the aircraft was still on the ground. The confusion over individual roles would have been resolved if the examiner had given a pre-flight briefing in line with the guidance contained in the FAA Designated Examiners' Handbook, but both pilots have stated that this briefing did not take place. In any event, the FAA Handbook and FARs are unclear on who should be the commander of the flight although FAR 61.47 states the examiner is not normally to be the Pilot in Command except by prior agreement with the applicant or other person who would normally be acting as Pilot in Command. Nevertheless, it is clear that the instructor should have been briefed that he was fulfilling the safety pilot role and was responsible for "protect(ing) the overall safety of the flight to whatever extent is necessary". If the instructor had clearly understood this responsibility, he might have monitored the owner's actions more closely during the touch-and-go and might have intervened earlier. Notwithstanding the confusion, the instructor took control when he considered that the owner was not taking appropriate action to control the aircraft, although the actual moment that he took control is in dispute. Given the owner's belief that the instructor was the commander and that the instructor was in any case by far the more experienced pilot, it is not surprising that he relinquished control even though, unknowingly, he had a more complete understanding of the aircraft's predicament. The flight time from the propeller strikes to the next ground impact was only a few seconds. Once the aircraft became airborne with a significant amount of power applied and a badly damaged left propeller, the situation was well beyond any emergency for which either pilot might have trained. The options for action were very limited and would have required a full appreciation of the circumstances, plus extremely rapid analysis and reactions if those actions were to be successful.

The flight crew's failure to cycle the deice boots prior to conducting a simulated forced landing and their failure to maintain adequate airspeed during the maneuver, which resulted in an inadvertent stall and subsequent loss of control. A contributing factor was the ice accumulation on the leading edges of the airfoils.

By clear and convincing evidence, the cause of this mishap was an uncharacteristic loss of situational awareness by the entire mishap flight deck crew and the subsequent lack of an appropriate response to obstacle warnings. The Board President further found the following factors substantially contributed to the mishap: overall crew preparation, a misdirected focus on the weather, crew resource management dynamics, and crew judgment as it relates to existing directives.

Engine failure for unknown reasons.

The accident was caused by the combination of the following factors:
- The erroneous actions of the flight engineer when trying to lower the landing gear,
- Failure of the flight crew to conduct the necessary (final approach) checks,
- The failure by the crew to check and respond to landing gear warning indications,
- The execution of a flight with an incomplete composition of crew, causing additional workload on the flight engineer during the approach (height and speed call outs),
- Late commands to go around by the air traffic controller,
- On the Yak-40 the landing gear handle moves to the opposite direction for retraction and lowering compared to the Antonov 24 (the flight mechanic had more, and recent, flight experience on the Yakovlev 40 jet),
- The large workload and fatigue of the crew during the recent six days before the incident.

It is estimated that the accident was caused as follows:
The aircraft was being operated on a training flight at Shimoji-Shima Airport, and was making a one-engine-out touch-and-go landing with the right engine simulated inoperative. The touchdown was late and beyond the normal aim point, and on the direction of the instructor, the trainee pilot attempted to go around on only the left engine. However, the trainee mishandled the aircraft, and then, seeing the instructor advance the right engine’s thrust lever, he applied right rudder pedal mechanically. This coincided with an increase in the rotation speed of the left engine, and the aircraft’s attitude suddenly changed towards the right. Because the trainee pilot could not fully correct this and the instructor was late in taking over control, the aircraft veered off the east side of the runway into a grass area and was damaged. Moreover, it is estimated that the following causal factors contributed to the accident:
1) The instructor did not take over when he directed the trainee to go around, or at an earlier stage, because he thought to allow the trainee pilot to handle the aircraft as much as possible, and because he did not sufficiently recognize that a go-around with one-engine simulated inoperative is a difficult maneuver for an inexperienced pilot.
2) Regarding the instructor’s intent to allow the trainee pilot to handle the aircraft as much as possible, the company’s instructional guidelines contained statements meaning that a judgment to go around should be made by the trainee pilot, and that during simulated one-engine-out touch-and-go training landings, the go-around after landing should continue with one engine simulated inoperative.
3) Regarding the instructor’s insufficient recognition of the difficulty of a go-around with one engine simulated inoperative for an inexperienced pilot, the instructor had not been trained to deal with the situation encountered in the accident, and the company’s regulations and manuals did not describe considerations on the difficulty of executing a go-around with one-engine simulated inoperative for an inexperienced pilot or on the effects of the wind on such maneuvers.
4) Regarding the delay in the instructor taking over control of the aircraft, the instructor was not following with his hands on the control wheel and was not in a position to take over immediately if necessary, and when the instructor had changed from being a simulator instructor to a flight instructor, he had not received sufficient training on cautionary matters regarding training in actual aircraft.