Accident to the Mudry Cap10BK registered F-GGYC on 23/05/2021 at Peyrolles-en-Provence
Loss of control during an aerobatic flight, collision with surface of a lake
After five minutes and thirty seconds, during which the pilot performed several aerobatic figures under G-forces, he performed inverted flight for about ten seconds and then switched back to normal flight. During this manoeuvre, the G-force increased from approximately -1.9 g to +1.6 g in five seconds. The aircraft's flight path then curved sharply towards the ground as a result of a nose-down input on the elevator. The G-force decreased and reached -3.9 g. Based on the accelerometer data, this final path is similar to an English bunt manoeuvre. The aircraft continued its vertical path towards the ground until it collided with the surface of the lake.
The investigation was not able to determine with certainty whether the action on the controls was deliberate or not.
The following hypotheses can be envisaged to explain the loss of control by the pilot:
- The occurrence of partial or total incapacitation resulting from a succession of figures under negative and positive G-forces and which ended with a high negative G-force. This incapacitation may have taken the form of G-induced almost loss of consciousness (A-LOC), G-induced loss of consciousness (G-LOC), a malaise due to a heart problem or another type of problem, or spatial disorientation. The pilot's medication for high blood pressure may have reduced his tolerance to the acceleration changes.
- The uncontrolled performance of an aerobatic figure by the pilot.
- The occurrence of an untimely event on board during the performance of the figure after passing the vertical axis (e.g. object incorrectly secured in the cockpit, reflex action of the passenger) which could have disturbed the pilot.
The occurrence of a technical malfunction, which the investigation was unable to rule out with certainty.
Medical fitness criteria for performing aerobatics in a non-competition context
The investigation has shown that there is no particular medical requirement to define medical fitness criteria for performing aerobatics in a non-competition context. However, there are physiological characteristics that allow the assessing medical examiner to exclude the performance of aerobatics.
The pronouncing of a "no aerobatics" limitation is conditioned by the finding of a deviation from the standard and a referral to the authority, whereas the physiological conditions for exclusion from aerobatics can exist without a deviation from the standard. This is why these physiological conditions should be specifically sought, beyond the class 2 medical certificate standard.
The BEA recommends that:
- whereas there is no requirement beyond the class 2 medical certificate for performing aerobatics in a non-competition context;
- whereas aerobatic flight, whatever its performance level, exposes the pilot to physiological stress which exceeds that in everyday life and in light aviation;
- whereas performing aerobatics presents numerous risks, in particular cardiovascular risks, to be taken into account by medical examiners, in particular when issuing the
class 2 medical fitness certificate; - whereas the absence of identified medical criteria allowing medical examiners to refer a pilot's file to the authority in order to examine a possible aerobatic limitation;
- whereas there is no obligation to hold a certificate indicating that there is no contraindication to the pilot performing aerobatics in a non-competition context;
the DSAC, through its medical centre, raise the awareness of the approved aviation medical examiners so that they can give suitable advice corresponding to the state of health of the pilots performing aerobatics, and prescribe, if necessary, a medical examination to assess as fully as possible their ability to withstand the physiological stresses associated with this activity. [Recommendation FRAN-2023-011]
The follow-up of this recommendation has been completed. Please consult SRIS2 for information about the adequate response to this recommendation.
Consequences of “push-pull effect” and risks associated with G-LOC
The BEA recommends that:
- whereas aerobatic flight, whatever its performance level, exposes the pilot to physiological stress which exceeds that in everyday life and in light aviation;
- whereas there may be a succession of negative G-force manoeuvres followed by positive G-force manoeuvres even when performing basic aerobatics;
- whereas the harmful effects of this type of succession of manoeuvres is not
sufficiently known; - whereas a pilot's tolerance to G-forces may be affected by various factors related to his/her physical condition and lifestyle;
- whereas the potentially fatal consequences of an impairment or loss of consciousness
in flight:
the FFA make aerobatic pilots aware of the danger of certain manoeuvres which can lead to the physiological limits of the human body being reached. [Recommendation
FRAN-2023-012]
This recommendation is being processed. Its status can be consulted on SRIS2.
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Note: in accordance with the provisions of Article 17.3 of Regulation No 996/2010 of the European Parliament and of the Council of 20 October 2010 on the investigation and prevention of accidents and incidents in civil aviation, a safety recommendation in no case creates a presumption of fault or liability in an accident, serious incident or incident. The recipients of safety recommendations report to the issuing authority in charge of safety investigations, on the measures taken or being studied for their implementation, as provided for in Article 18 of the aforementioned regulation.