Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Model 777-200 and -300 series airplanes. This proposed AD would require repetitive inspections of all thrust reverser (T/R) structure and sealant for degradation, and related investigative and corrective actions if necessary. This proposed AD results from reports of thrust reverser events related to thermal damage of the thrust reverser inner wall. We are proposing this AD to detect and correct a degraded T/R inner wall panel, which could lead to failure of a T/R and adjacent components and their consequent separation from the airplane, which could result in a rejected takeoff (RTO) and cause asymmetric thrust and consequent loss of control of the airplane during reverse thrust operation. If a T/R inner wall overheats, separated components could cause structural damage to the airplane, damage to other airplanes, or possible injury to people on the ground.