Operators of ATR turboprops are being instructed to conduct urgent checks for possible wrongly-assembled valves on the engine fire-extinguishing systems.
The European Union Aviation Safety Agency has ordered the checks in an emergency directive which covers both the ATR 42 and 72, up to the -500 variants.
EASA states that a scheduled maintenance operation identified incorrect marking and assembly of two-way valves in the left- and right-hand fire-extinguishing systems.
As a result, says the regulator, the systems “did not operate as intended”.
Similarly-affected systems could suffer from “reduced performance” in the event of an engine fire, it adds.
ATR has issued inspection and rework instructions for the parts involved.
EASA is requiring operators to carry out a functional check of these parts, within 21 days, and undertake corrective measures if necessary – including replacing affected components before the next flight.
Older-variant ATRs are powered by Pratt & Whitney Canada PW124 or PW127 engines.
