Toussus-le-Noble

Investigation did not reveal any technical element that could have contributed to the accident. However, considering the fact that the aircraft was totally destroyed upon impact, it was not possible to carry out all the examinations generally carried out on a wreck. It is possible the aircraft was flying in moderate icing conditions. Investigation could not determine if the deicing systems were activated. However, analysis of the flight path shows that the cruising speed was stable until the descent, which tends to indicate an absence of icing of the aircraft in normal cruise. A rapid and heavy icing of the aircraft during the descent making the aircraft to be difficult to control seems unlikely given the icing conditions predicted by Météo France. Investigations were unable to determine the reasons for the loss of control. Maybe it occurred during an unusual situation or any failure. Whatever the reasons, the lack of experience of the pilot on TBM-700, especially in the absence of visual references, may increase his workload beyond his capabilities, not allowing him to regain control of the aircraft. Once the loss of control occurred, given the weather conditions, it is very likely that the pilot did not recover any visual references until the collision with the ground.

The trace from the radar data shows that the aircraft followed the ILS Z 26 procedure track in the horizontal plane to about 6.4 NM from the runway threshold. This observation is consistent with the autopilot tracking of the ILS Z 26 procedure entered into the FMS in GPS mode. The transition from GPS to LOC occurred after the FAP. Although the APP mode was engaged, the aircraft did not descend as expected by the pilot. It continued in line with the localizer but in level flight at 4000 feet for more than 1 nm. The pilot attempted to catch up with the glide path from above. Unable to stabilize his course, he aborted the approach without following the prescribed go-around path or the heading and altitude instructions provided by the controller. He made a succession of left and right turns and climbs and descents. The track and readbacks show that he lost situational awareness. The airspeed regression following the last climb caused the pilot to lose control of the aircraft, which collided with the ground. The entire approach was flown with no outside visibility.
Contributing factors (may have contributed to the loss of control):
- A coding error in the Garmin 1000 avionics suite database that prevented the automatic transition from GPS mode to LOC mode. Thus the automatic interception of the descent plan did not occur, which probably surprised the pilot and led him to resume manual piloting with excessive corrections.
- The pilot's overconfidence in the aircraft's autopilot system.
- Lack of knowledge of the conditions required for the aircraft autopilot system to capture and track the glide path.
- Lack of consistency verification by the pilot between the coded procedure in the avionics suite and his breakthrough sheet.
- The pilot's lack of total and recent instrument flight experience without external visual reference, which may have contributed to his increased stress, lack of availability, and spatial disorientation.
- Sensory illusions that the pilot may have been confronted with, given the numerous changes in aircraft attitude, without external visual reference.
- The acquisition of additional experience and skills with safety pilots after obtaining the SET class rating, which is ineffective and outside the regulatory training framework, which can lead pilots to free themselves from this support when it is considered to be restrictive.

Loss of control while approaching at a speed close to stall speed in clouds without any external visual references, in a phase of flight where the pilot encountered difficulties. Investigations were unable to determine the exact cause of the loss of control and the reason why the pilot was unable to regain control.

Examination of the engine revealed a tightening defect in the connecting rod heads. The rupture of one of them caused a loss of oil pressure and damage to the movable coupling of the engine, which had been subject to repairs in March 2000 following a belly landing.

The loss of control is probably the consequence of a rapid icing of the airframe insufficiently or belatedly taken into account by the pilot. The following factors may have contributed to the accident:
- The pilot's fatigue generated by a flight period of 8 hours and 30 minutes in a single pilot configuration,
- The single pilot configuration imposes a high workload during a VOR-DME approach.

The accident was due to the loss of control of the aircraft during the initial climb phase, which may be linked to a power asymmetry between the two engines. He was not possible to determine the origin of this asymmetry, nor its effective contribution to the accident.

The pilot was completing the approach under VFR mode in IMC conditions, resulting in a controlled flight into terrain.

The exact cause of the loss of control could not be established. Technical analysis did not reveal any anomalies on the engine and other aircraft's equipments. Brand new, the aircraft had just been delivered and completed 50 flying hours only. The pilot, relatively inexperienced, totalized 150 hours on type. It is possible that he mismanaged the engine and other equipments.