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94-25-09 Rolls-Royce, plc: Amendment 39-9093. Docket 93-ANE-43.
Applicability: Rolls-Royce, plc (R-R) Spey 506-14 series, 511-14 series, and 555-15 series turbofan engines, installed on but not limited to British Aerospace BAC 1-11 series and Fokker F28 series aircraft.
Compliance: Required as indicated, unless accomplished previously.
To prevent a high pressure turbine (HPT) or low pressure turbine (LPT) disk burst due to cracking attributed to corrosion, which may result in an uncontained engine failure, accomplish the following:
(a) Perform a one-time inspection for cracks and corrosion pitting in stage 1 and stage 2 HPT disks that on the effective date of this airworthiness directive (AD) have completed 40% or more of their published Group "A" lives, in accordance with the procedures and schedule described in R-R Service Bulletin (SB) No. Sp72-1044, dated September 1992, at the next shop visit after the effective date of this AD.
(b) Perform a one-time inspection for cracks and corrosion pitting in stage 1 and stage 2 HPT disks that on the effective date of this AD have completed less than 40% of their published Group "A" lives, in accordance with the procedures and schedule described in R-R SB No. Sp72- 1044, dated September 1992, at the first shop visit after completing 40% of their published Group "A" lives.
(c) Perform a one-time inspection for cracks and corrosion pitting in stage 1 and stage 2 LPT disks that on the effective date of this AD have completed 40% or more of their published Group "A" lives, in accordance with the procedures and schedule described in R-R SB No. Sp72- 1044, dated September 1992, at the next shop visit after the effective date of this AD.
(d) Perform a one-time inspection for cracks and corrosion pitting in stage 1 and stage 2 LPT disks that on the effective date of this AD have completed less than 40% of their published Group "A" lives, in accordance with the procedures and schedule described in R-R SB No. Sp72- 1044, dated September 1992, at the first shop visit after completing 40% of their published Group "A" lives.
(e) Replace with a serviceable part, disks that do not meet the inspection requirements described in section 72-50 of the applicable R-R Spey Engine Overhaul Manual, prior to return to service.
(f) Mark disks that meet the inspection requirements described in section 72-50 of the applicable R-R Spey Engine Overhaul Manual in accordance with R-R SB No. Sp72-1044, dated September 1992, prior to return to service.
(g) For the purpose of this AD, a shop visit is defined as an engine removal where engine maintenance entails removal of either HPT or LPT disks.
(h) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(i) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished.
(j) The inspection, and replacement, if necessary, of the disks, shall be done in accordance with the following service bulletin:
Document No.
Pages
Date
R-R SB No. Sp72-1044
1-2
September 1992
Total Pages: 2.
This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Service Manager, Spey engines, Rolls-Royce, plc, East Kilbride, Glasgow G74 4PY, Scotland. Copies may beinspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street NW., suite 700, Washington, DC.
(k) This amendment becomes effective on February 17, 1995.
