AD NUMBER: 2012-12-03

PRODUCT: All Rolls-Royce plc (RR) models RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and 980-84 turbofan engines.
SUBJECT: Airworthiness Directive 2012-12-03
ACTION: Final Rule; request for comments.

SUMMARY: The FAA is superseding an existing airworthiness directive (AD) for the products listed above.

 That AD currently requires inspecting the intermediate-pressure (IP) shaft rigid coupling splines for wear resulting in rearward movement of the IP turbine.

This AD requires the same inspections, and new inspections based on possible changes in wear rate. This AD was prompted by RR identifying wear beyond engine manual limits on the abutment faces of the splines. RR also determined that an additional IP shaft rigid coupling configuration requires inspection.

The FAA is issuing this AD to detect wear on the abutment faces of the splines, which could result in loss of disc integrity, an uncontained failure of the engine, and damage to the airplane.

DATES: This AD is effective July 17, 2012. Comments are due no later than August 16, 2012.

FMI: AD