Summary
We propose to adopt 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 proposed AD was prompted by the discovery of a cracked and distorted front combustion liner (FCL) metering panel, which was made from the wrong material. This proposed AD would require a one-time inspection of the FCL metering panel to determine if it was made from N75 material and replacing it with one made from C263 material if it was made from N75 material. We are proposing this AD to prevent hot gas burning through the engine casing, which could result in an under-cowl fire and damage to the airplane.