airworthiness · Rule · Final rule; request for comments. · Published 2013-01-30 · Effective 2013-02-14 · 78 FR 6206
Document
Document number
2013-01361
Federal Register citation
78 FR 6206
Type
Rule
Action
Final rule; request for comments.
Category
airworthiness
Manufacturer
Rolls-Royce plc Turbofan
Publication date
2013-01-30
Effective date
2013-02-14
FAA docket
Docket No. FAA-2013-0030
Abstract
We are adopting a new airworthiness directive (AD) for all Rolls-Royce plc RB211-Trent 970-84, RB211-Trent 970B-84, RB211-Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84 and RB211-Trent 980-84 turbofan engines. This AD requires on-wing inspections of low-pressure turbine (LPT) disk seal fins and interstage seals when post-flight review indicates Engine Health Monitoring (EHM) vibratory maintenance-alert limits were exceeded in flight. The AD also requires in-shop inspections of the LPT disk seal fins and interstage seals to detect cracks or damage and, depending on the findings, accomplishment of corrective action. This AD is prompted by a Trent 900 engine experiencing LPT stage 2 disk interstage seal material loss and increased low-pressure rotor vibration while in flight. We are issuing this AD to prevent cracks in the LPT disk, which could result in uncontained engine failure and damage to the airplane.