airworthiness · Rule · Final rule; request for comments. · Published 2012-07-02 · Effective 2012-07-17 · 77 FR 39157
Document
Document number
2012-15985
Federal Register citation
77 FR 39157
Type
Rule
Action
Final rule; request for comments.
Category
airworthiness
Manufacturer
Rolls-Royce plc Turbofan
Publication date
2012-07-02
Effective date
2012-07-17
FAA docket
Docket No. FAA-2010-0748
Abstract
We are superseding an existing airworthiness directive (AD) for 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. 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. We are 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.