2008-23-04 Rolls-Royce plc: Amendment 39-15725.; Docket No. FAA- 2008-1063; Directorate Identifier 2008-NE-32-AD.
Effective Date
(a) This airworthiness directive (AD) becomes effective December 1, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Rolls-Royce plc (RR) RB211 Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, and 560A2-61 turbofan engines that have not incorporated RR Service Bulletin (SB) No. RB.211-72-D733, dated August 21, 2002, or Revision 1 of that SB, dated March 6, 2008. These engines are installed on, but not limited to, Airbus A340-500 and -600 series airplanes.
Reason
(d) European Aviation Safety Agency (EASA) AD No. 2008-0109 R1, dated June 17, 2008, states that for RB211 Trent 500 series turbofan engines that have not incorporated RR SB No. RB.211-72-D733, dated August 21, 2002, or Revision 1 of that SB, dated March 6, 2008, the unsafe condition is as follows:
The intermediate-pressure (IP) turbine blade shrouds of the RB211 Trent 500 series engines feature closure welds (dust caps). Development engine testing has revealed the potential for dust caps to crack, lift and release. The latter may potentially allow hot annulus gas to be ingested down the core passages of IP turbine blades. Radial inflow of annulus gas into the IP disc rim region could cause local heating of the disc firtree, resulting in creep of the disc material. Failure of the disc rim in creep could simultaneously release two blades and a disc post. Failure to this extent could be beyond the containment capabilities of the casing. Consequently, release of the dust caps would constitute a potentially unsafe condition.
We are issuing this AD to prevent uncontained release of IP turbine blades and disc posts, resulting in damage to the airplane.
Actions and Compliance
(e) Unless already done, do the following actions.
(1) Within 5 flight cycles, on engines installed or not installed, carry out the initial borescope inspection of the IP turbine blade outer shroud dust caps, using Section 3, Accomplishment Instructions of RR Alert Service Bulletin (ASB) No. RB.211-72-AF994, Revision 1, dated September 1, 2008.
(2) Thereafter, depending on the results of the inspection specified in paragraph (e)(1) of this AD, follow the appropriate action in the following Table 1:
Table 1--Required Actions and Compliance Times
Results of Borescope Inspection
Actions That Must Be Carried Out
(i) Total number of IP turbine blade outer shroud dust caps lifting is 0.
At intervals not to exceed 100 cycles, re-inspect the dust caps using Section 3, Accomplishment Instructions of Rolls-Royce plc ASB No. RB.211-72-AF994, Revision 1, dated September 1, 2008.
(ii) Total number of IP turbine blade outer shroud dust caps lifting exceeds 0 but is equal to or fewer than 10.
At intervals not to exceed 20 cycles, re-inspect the dust caps using Section 3, Accomplishment Instructionsof Rolls-Royce plc ASB No. RB.211-72-AF994, Revision 1, dated September 1, 2008.
(iii) Total number of IP turbine blade outer shroud dust caps lifting exceeds 10 but is equal to or fewer than 20.
At intervals not to exceed 10 cycles, re-inspect the dust caps using Section 3, Accomplishment Instructions of Rolls-Royce plc ASB No. RB.211-72-AF994, Revision 1, dated September 1, 2008.
(iv) Total number of IP turbine blade outer shroud dust caps lifting exceeds 20.
Within 10 cycles, remove the engine from service and install core restrictor plugs in the IP turbine blade roots, using Section 3, Accomplishment Instructions of RR Service Bulletin (SB) No. RB.211-72-D733, Revision 1, dated March 6, 2008.
(v) Total number of IP turbine blade outer shroud dust caps missing exceeds 1.
Before further flight, remove the engine from service and install core restrictor plugs in the IP turbine blade roots, using Section 3, Accomplishment Instructions of RR SB No. RB.211-72-D733, Revision 1, dated March 6, 2008.
FAA AD Differences
(f) This AD differs from the Mandatory Continuing Airworthiness Information (MCAI) EASA AD by requiring the initial borescope inspection to be done within 5 flight cycles. The MCAI required the initial inspection to be done before July 1, 2008, which has already passed.
(g) Alternative Methods of Compliance (AMOCs): The Manager, Engine Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.
Related Information
(h) Refer to MCAI EASA AD 2008-0109 R1, dated June 17, 2008, for related information.
(i) Contact James Lawrence, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail:
[email protected]; telephone (781) 238-7176; fax (781) 238- 7199, for more information about this AD.
Material Incorporated by Reference
(j) You must use the Rolls-Royce plc service information specified in the following Table 2 to do the actions required by this AD.
Table 2--Material Incorporated by Reference
Document No.
Page
Revision
Date
Alert Service Bulletin No. RB.211-72-AF994
Total Pages: 24
All
1
September 1, 2008
Service Bulletin No. RB.211-72-D733
Total Pages: 8
All
1
March 6, 2008
Supplement to
Service Bulletin No. RB.211-72-D733
Total Pages: 1
All
1
March 6, 2008
(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) For service information identified in this AD, contact Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, UK, telephone 44-0- 1332 242424; fax 44-0-1332 249936.
(3) You may review copies at the FAA, New England Region, 12 New England Executive Park, Burlington, MA; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.
