Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain Rolls-Royce plc (RR) RB211-524B-02; -524B2-19; -524B3-02; -524B4-02; - 524C2-19; -524D4-19; -524D4-B-19; -524D4-39; -535C-37; -535E4-37; - 535E4-B-37, and -535E4-B-75 turbofan engines, and all RB211-524G2-19; - 524G3-19; -524H2-19; and -524H-36 turbofan engines. This AD requires a one-time inspection of the front combustion liner (FCL) metering panel to determine if it is made from N75 material and, if so, replacing it with an FCL made from C263 material. This AD was prompted by the discovery of a cracked and distorted FCL metering panel, which was made from N75 material. We are issuing this AD to prevent hot gases from burning through the engine casing, which could result in an under-cowl fire and damage to the airplane.