[CORRECTED VERSION] Insufficient clearance between a wire-bundle bracket screw and a hydraulic pipe feeding an engine component on certain ATR aircraft is causing damage to the pipe, leading the European Aviation Safety Agency (EASA) to call for modifications of the bundles.

“Several occurrences were reported of finding interference and chafing between a propeller brake hydraulic pipe and an electrical wire bundle bracket screw installed in the underwing box of the right-hand (RH) engine nacelle,” EASA explained in a draft directive published Sept. 4.

EASA did not cite any reports of in-service leaks, but said the risk of a ruptured tube and subsequent fire in “a non-fire resistant area of the RH engine nacelle” is sufficient enough to warrant action.

The pipe is only pressurized on the ground, and the risk of leakage is only during propeller brake activation or deactivation, EASA explained.

The proposed remedy: adjust the wire bundles and conduct follow-up inspections. EASA proposes modifying the wire-bundle routing within 5,000 hours or 24 months after the directive’s effective date, whichever comes later. Operators would then perform a one-time inspection to ensure proper clearance between the bundle bracket screw and pipe.

EASA’s draft directive is based on recommendations made by ATR in-service instructions sent to operators in July and August. Affected models include both ATR 42s and ATR 72s with ATR modifications 01872 and 07953 done during production, EASA said.

Sean Broderick, sean.broderick@aviationweek.comSean Broderick, sean.broderick@aviationweek.com

This story has been corrected to reflect the proposed directive’s actions, including an inspection following the proposed modification.