Accident to the fixed-wing microlight WT9 DYNAMIC CLUB identified 67BVN on 12/04/24 at Peynier

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• Safety recommendations

During a stall exercise performed by the instructor, at a speed close to the stall speed, the microlight entered a right-hand roll. The instructor thought he had entered a left-hand spin. He briefly increased engine power to maximum and then returned to idle. The angle of attack continued to increase. The data recorded was unable to determine a potential asymmetry during the exercise.

When the microlight entered a right-hand roll, it is possible that the instructor made a reflex input on the stick to counter this start of roll.

Control of the microlight was lost and the instructor did not manage to regain it. Having heard a noise coming from the rear of the microlight, the instructor thought there was a structural failure and activated the airframe parachute.

The BEA issues two safety recommendations:

- Recommendation FRAN-2025-007 / Installation of stall strips on WT9s which are not so equipped

The BEA recommends that:

- whereas the stall behaviour of the "high performance" WT9 microlight can be disconcerting compared to an older design microlight with a substantially lower wing loading;
- whereas the tests conducted by Aerospool show that the installation of stall strips improves stall behaviour;
- whereas during the tests for obtaining the LSA certification for the WT9, the installation of stall strips was necessary to meet LSA stall requirements;
- whereas the French Directive dated 23 September 1998 as amended (Article 13) allows the DSAC to impose operational or airworthiness directives for safety reasons;
- whereas the French Directive dated 23 September 1998 as amended (Article 13) allows the DSAC to impose operational or airworthiness directives for safety reasons;
- whereas the WT9 microlights produced before 2018 were not originally equipped with stall strips and a large number of WT9 microlights produced before this date are identified
in France;
- whereas 130 to 150 WT9 microlights not equipped with stall strips are registered in France;
- whereas many WT9 microlights are used in flying schools, including for primary flight training, and stall exercises are therefore regularly performed;
- whereas the DSAC is the only authority provided with the possibility of making the implementation of a Service Bulletin mandatory for microlights in France;

the DSAC make the implementation of Service Bulletin ZBWT9 31A / 2024 (Installation of safety equipment - stall strips) mandatory for all Dynamic WT9 microlights which are not so equipped.

- Recommendation FRAN-2025-008 / Request for special airworthiness conditions for "high-performance" Class 3 microlights

The BEA recommends that:

- whereas a growing number of "high-performance" microlights is used, in particular in flying schools (including for primary flight training);
- whereas the stall behaviour of these "high performance" WT9 microlights can be disconcerting compared to a microlight with a substantially lower wing loading;
- whereas microlight pilots and instructors rarely train in spin recovery;
- whereas a substantial number of loss of control occurs in "high performance" microlights, in particular as part of the accidents mentioned in paragraph 2.9;
- whereas the French Directive dated 24 June 2019pertaining to motorised microlights provides the DSAC with the possibility of imposing special airworthiness conditions on the manufacturers of Class 3 microlights with a wing loading at maximum weight greater than 30 kg/m2;

the DSAC impose, for newly designed Class 3 microlights, special airworthiness conditions regarding the microlight's approach and stall behaviours.

The recommendations are being processed.

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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.

BEA is the French air safety investigation authority for civil aviation. The sole objective of the investigation is to improve air safety. It is intended neither to apportion blame nor to assess responsiblity.