Ajaccio

Environmental area:
The load case studied during the investigations did not explain the observed fuselage failure. However, the characteristics of the upward aerological disturbance caused by the fire are likely to have generated airframe stresses of an order of magnitude close to that of the loads capable of causing the fuselage to fail. Given the uncertainties encountered during the evaluation of the parameters of the rising air column that affected the accuracy of the research results concerning the effects of the stresses on the airframe, the aerological phenomenon encountered represents a possible cause of the event.
Technical Area:
The research undertaken to find in-flight loads capable, in the context of the event, of breaking the intact fuselage without damaging the empennage was unsuccessful. Detailed observation of the airframe did not reveal any damage prior to the occurrence. However, the results of these investigations do not rule out the existence of such damage, so the hypothesis of prior damage to the airframe cannot be totally rejected.

Failure of the left engine during initial climb for unknown reasons.

The Committee considers that the cause of this accident was that the descent undertaken by the crew led the aircraft to find itself in clouds below the instruments safety altitude for that part of the flight path. The Committee noted that when the crew, alerted by the GPWS, tried to regain altitude, the maneuver proved to be insufficient to overcome the effect of strong descending air currents due to relief and strong wind, present in the area where the aircraft was flying at that time. The following contributing factors were reported:
- The committee felt that the crew did not show the necessary rigor when preparing its approach. It does not appear that a logical order has guided the crew in the revision and memorization of various parameters, including the safe altitude and the maximum speed of the holding circuit, which in any case, did not catch the attention of the crew in an appropriate manner. In addition, the presence of a young child on the observer seat cockpit, until the end of the flight was a dispersion factor of attention;
- The misunderstandings which have developed in the exchange of messages between the captain and the approach controller could disrupt, at certain times, the working conditions of the crew. The controller consequently did not have an accurate representation of the progress of the aircraft in the performance of its procedure and, therefore, did not intervene when two messages "call you inbound on radial two forty seven", and then "rolling inbound out of six thousand" would have told him, if he had better interpreted them, an ambiguous situation for the first and abnormal and dangerous for the second;
- The advice to the commission on vectoring habits and on habits supposedly used by some national air traffic services to systematically take into account the safety altitudes in formulating control permissions, leads to the suspicion that some crew have a slightest concern about the safe altitudes;
- Airspeed of the aircraft was greater than the maximum speed of the holding pattern and crew did not adopt the correction factors adapted to altitude wind they had encountered during the previous segment th flight. This led to the airplane overfly an area where, although it is included in the protected area of the holding pattern, the upper air movements were particularly important;
- The symbolic representation of the holding pattern on the approach chart used by the crew corresponds to a path, with no wind, and an aircraft which would have approximately 150 knots indicated airspeed. It calls not evident attention to Airmen on the actual dimensions of the actually travelled circuits in flight, nor therefore on altitude over the terrain reliefs.

The accident was the consequence of a controlled flight with ground during a night approach under CAT I conditions. The following contributing factors were reported:
- The pilot's experience on this type of aircraft was insufficient,
- The pilot failed to monitor his instruments,
- The aircraft was unstable on final approach,
- The airplane struck the ground without any corrective manoeuvre on part of the pilot who failed to initiate a go-around procedure,
- Poor weather conditions,
- Visibility below minimums,
- A CAT I approach to runway 14 was thoughtless,
- Excessive approach speed, 180 knots instead of the recommended 105-115 knots.

The exact cause of the accident could not be determined with certainty. At the beginning of the investigations, the board of inquiry reported that the following assumptions were not ruled out: pilot error, fire in the cockpit, aircraft shot down by a surface-to-air missile or the rupture of the hydraulic reservoir. Nevertheless, the aircraft totally disintegrated upon impact with the water surface as it was extremely violent, at a considerable speed and with a high rate of descent. It is believed the loss of control was the consequence of a fire that erupted in the rear part of the cabin, by the right lavatory and galley. Maybe the pilot became incapacitated by fumes but this was not confirmed. About 50 years after the accident, the French government may release some classified documents regarding this tragedy, reinforcing the assumption that the aircraft may have been shut down by a surface-to-air missile fired by the French Navy which was completing local exercises in the area at that time. In 2018, the real cause of this accident remains unclear.

The accident was attributed to a series of errors by the crew who:
- Made insufficient preparation for the flight and committed a serious error in estimating the duration of the flight,
- Failed to observe the cruising altitude entered on the flight plan,
- Failed to check properly the navigation of the aircraft which resulted in a wrong estimation of the position of the aircraft,
- Failed to maintain the safety altitude, and
- Started the descent prematurely, subsequently entering into instrument flight conditions.
The errors of the crew were made possible:
- By a lack of supervision of the flights on the part of the operator; and
- By a lack of correct route instructions for the segment Bastia-Ajaccio. The Board was led to conclude that the crew of F-BEIZ did not have the necessary instructions for the route via the turning point. Even supposing that the instructions supplied to the Board by the operator were issued before the accident, and that they were available to the pilot-in-command, the Board considered that these instructions were inaccurate and dangerous since they did not give the altitude at the turning point and they provided for a flight time between Bastia and Ajaccio which was incompatible with the attainment of safety altitudes.
- By a certain fatigue of the crew. Although the regulations concerning flight time limitations were strictly observed, it is worth mentioning that the flight activity of the crew was fairly strenuous during the three days preceding the accident.

Engine failure on approach.