13 October 2011
An Emergency Airworthiness Directive has been issued by the Direction Générale de l’Aviation Civile (France) with reference to the ‘abnormal wear’ on the flaperon system of the Dyn’Aero MCR Sportster. The AD currently applies to French registered aircraft only. The AD refers to two accidents involving MCR Sportsters – ‘In both cases, an abnormal wear of the leading screw and carriage of the aileron / flaps (flaperon) system has been identified. Such a wear could result in the loss of the aileron control and in the loss of control of the aeroplane (although the cause of the second accident has not been
formally identified at this stage).
The aim of this Airworthiness Directive (AD) is to mandate a periodic inspection of the flaperon control system. Depending on the BEA investigations and actions from the manufacturer, further measures, or a revision to the present measures, may be mandated at a later stage.’
Under the heading ‘Mandatory Actions and Compliance Times’, the AD continues:
The following measures are rendered mandatory from the effective date of this AD.
3.1 Before the next flight, disassemble and inspect the leading screw and the carriage of the flaperon control system, in accordance with the procedure described in DYN’AERO Service Bulletin in reference.
In addition to the instructions of the SB, the following instructions shall apply:
– No corrosion evidence of the screw is allowed
– No mechanical damage (tool impact, scratch) of the screw is allowed
– No material transfer between the screw and the bronze bushing is allowed
– Bronze bushing condition: use a new M6 screw and screw 5 turns, in one direction and in the other. No axial, radial play, backlash, is allowed.
– Leading screw thread: use a new H nut, screw in the full pitch of the screw. No axial, radial play, backlash, is allowed.
– Shape defect of the leading screw: roll the screw on a surface plate to check its straightness.
Any defect on one of the concerned parts necessitates the replacement of the leading screw and carriage concerned, before any further flight.
3.2 Repeat the inspection every 25 flight hours or 3 months, whichever occurs first.
3.3 In all cases, the result of the inspections shall be provided to DYN’AERO. The parts removed following a defect shall be returned to DYN’AERO. <a href=”http://http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=detail&id=4735″>Click here for more</a>
