Accident to the Centrair ASW20 registered F-CFFF on 03/06/2023 at Bailleau-Armenonville
Loss of pitch control during take-off, collision with ground, during a competition flight
The elevator ball of the glider showed abnormal wear requiring it to be replaced according to the criterion defined in the maintenance instructions included in the maintenance manual. This wear had not been detected during the last annual inspection. Furthermore, the ball and socket had been installed for more than 30 years, exceeding the replacement time limit indicated by the manufacturer, by more than 20 years.
The manufacturer, L’Hotellier, had introduced this periodic replacement criterion in an update of the maintenance instructions. The glider manufacturer, Centrair, had had knowledge of this. It had considered that it was not necessary to systematically carry out this replacement and had not transmitted this information to the operators of the ASW 20 F.
Centrair had not had knowledge of the following updates and as a consequence, neither had the users of its gliders.
The morning of the accident, the pilot had rigged the glider. As usual, he did not use a locking pin for the elevator ball and socket connector. He visually checked the connection. In the afternoon, during the take-off, the pilot lost pitch control of the glider which collided with the ground.
The observations made of the elevator ball and socket connector seem to show that it was incorrectly or not connected following the rigging of the glider the day of the accident.
However, abnormal wear of the ball, associated with the take-off bounces may have created excessive loads on the connector. The disconnection of the elevator ball and socket connector cannot therefore be totally excluded.
The BEA issues three safety recommendations:
- Recommendation FRAN-2025-002 / Securing L'hotellier ball and socket connectors
The BEA recommends that:
- whereas the use of a locking pin is indicated by L’Hotellier in the ball and socket maintenance instructions;
- whereas Airworthiness Directives were issued by several civil aviation authorities including the German (before the creation of EASA) and American authorities to make the securing of the L’Hotellier connectors mandatory;
- whereas these Directives were not adopted by EASA and are not applicable in France;
EASA impose the locking of L’Hotellier connectors, notably by means of a locking pin, on aircraft using these connectors for critical parts such as the flight controls.
- Recommendation FRAN-2025-003 & FRAN-2025-004 / Distribution of maintenance instructions
The BEA recommends that:
- whereas the L’Hotellier procedures do not provide for the distribution of updates to IMA 10.01 to type certificate holders;
- whereas L’Hotellier and Centrair have not formalized by contract or arrangement, the distribution of these maintenance instructions;
- whereas at the time of the certification of the ASW 20 F, the drawing up of a contract between light aircraft manufacturers and their part suppliers was unusual;
- whereas the updates to IMA 10.01 have a safety benefit, in particular with the addition of a periodic replacement criterion for balls and sockets implying a service life limit for these parts;
- whereas there are many type certificate holders using L'Hotellier balls and sockets;
- whereas for certain aircraft, these parts are installed on flight controls;
- whereas the several manufacturers contacted during the investigation did not have knowledge of the updated maintenance instructions introducing a periodic replacement criterion;
EASA, in coordination with L’Hotellier, ensure that the maintenance instructions contained in IMA 10.01 are effectively distributed to all type certificate holders using L'Hotellier connectors on their aircraft;
EASA raise awareness among type certificate holders of light aircraft about the need to monitor updates to maintenance information published by critical component suppliers.
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.