[Federal Register Volume 59, Number 234 (Wednesday, December 7, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-28378]


[[Page Unknown]]

[Federal Register: December 7, 1994]


-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-ANE-31; Amendment 39-9072; AD 94-23-09]

 

Airworthiness Directives; Rolls-Royce, plc Spey Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment supersedes telegraphic airworthiness directive 
(AD) T89-02-52, which superseded Telegraphic AD T88-22-51 (AD), 
applicable to Rolls-Royce, plc (R-R) Spey series turbofan engines. 
Telegraphic AD T88-22-51 reduced cyclic life limits for seventh stage 
high pressure compressor (HPC) disks from 40,000 total part cycles in 
service (TPC) to 35,000 TPC for the R-R Spey Model 506-14 and -14D 
engines. Telegraphic AD T89-02-52 currently requires repetitive 
inspections or further reduced cyclic life limits for seventh stage HPC 
disks. This amendment increases the AD's effectivity to include 
additional   R-R Spey engine models, eliminates the option for 
repetitive inspections, and further reduces the cyclic life limits. 
This amendment is prompted by further investigation into disk bore 
cracking that was caused by corrosion. The actions specified by this AD 
are intended to prevent a seventh stage HPC disk burst due to cracking 
attributed to corrosion, which may result in an uncontained engine 
failure.

DATES: Effective January 6, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 6, 1995.

ADDRESSES: The service information referenced in this AD may be 
obtained from Service Manager, Spey engines, Rolls-Royce, plc, East 
Kilbride, Glasgow G74 4PY, Scotland. This information may be examined 
at the Federal Aviation Administration (FAA), New England Region, 
Office of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA 01803-5299; or at the Office of the Federal Register, 
800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Fisher, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7149, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: The Civil Aviation Authority (CAA), which is 
the airworthiness authority of the United Kingdom, notified the Federal 
Aviation Administration (FAA) that an unsafe condition may exist on 
Rolls-Royce, plc (R-R) Spey series turbofan engines. The CAA advised 
that they received a report of a three-inch crack extending radially 
outward from the bore on a seventh stage high pressure compressor (HPC) 
disk installed in a R-R Spey Model 506-14D engine. The crack originated 
from a corrosion pit that apparently had been present at the disk's 
entry into service. Investigation indicated that failure of the engine 
due to disk burst was imminent. That condition, if not corrected, could 
result in a seventh stage HPC disk burst due to cracking attributed to 
corrosion, which may result in an uncontained engine failure.
    This engine model is manufactured in the United Kingdom and is type 
certificated for operation in the United States under the provisions of 
Section 21.29 of the Federal Aviation Regulations and the applicable 
bilateral airworthiness agreement. Pursuant to this bilateral 
airworthiness agreement, the CAA has kept the FAA informed of the 
situation described above. The FAA has examined the findings of the 
CAA, reviewed all available information, and determined that 
airworthiness directive (AD) action is necessary for products of this 
type design that are certificated for operation in the United States.
    On October 20, 1988, the FAA issued Telegraphic AD T88-22-51, which 
reduced cyclic life limits for seventh stage HPC disks from 40,000 
total part cycles in service (TPC) to 35,000 TPC for the R-R Spey Model 
506-14 and -14D engines. On January 26, 1989, the FAA issued 
Telegraphic AD T89-02-52, which supersedes Telegraphic AD T88-22-51, 
and currently requires repetitive inspections or further reduced cyclic 
life limits for seventh stage HPC disks.
    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) by superseding Telegraphic AD T89-02-52 was published in 
the Federal Register on January 11, 1994 (59 FR 1500). That action 
proposed to increase the AD's effectivity to include additional R-R 
Spey engine models, eliminate the option for repetitive inspections of 
seventh stage HPC disks, further reduce the cyclic life limits, and 
require removing from service disks that exceed the revised cyclic life 
limits following the schedule established in this AD.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comment received.
    The commenter concurs with the rule as proposed.
    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    The FAA estimates that 173 engines installed on aircraft of U.S. 
registry will be affected by this AD, and that it will not take any 
additional work hours per engine to accomplish the required actions. 
Replacement parts, prorated for the reduced life, will cost 
approximately $1,718 per engine. Based on these figures, the total cost 
impact of the AD on U.S. operators is estimated to be $297,214.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air Transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-23-09  Rolls-Royce, plc: Amendment 39-9072. Docket 93-ANE-31. 
Supersedes Telegraphic AD T89-02-52, dated January 26, 1989.

    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 and Fokker F28 aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a seventh stage high pressure compressor (HPC) disk 
burst due to cracking attributed to corrosion, which may result in 
an uncontained engine failure, accomplish the following:
    (a) For seventh stage HPC disks that on the effective date of 
this airworthiness directive (AD) exceed the revised cyclic life 
limits described in R-R Mandatory Service Bulletin (SB) Sp72-1034, 
Revision 1, dated May 1990, remove from service and replace with a 
serviceable part within 60 days after the effective date of this AD.
    (b) For seventh stage HPC disks that on the effective date of 
this AD do not exceed the revised cyclic life limits described in R-
R Mandatory SB Sp72-1034, Revision 1, dated May 4, 1990, remove from 
service and replace with a serviceable part: either prior to 
exceeding the revised cyclic life limits, or within 60 days after 
the effective date of this AD, whichever occurs later.
    (c) 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 method of compliance with this AD, if any, may be 
obtained from the Engine Certification Office.

    (d) 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.
    (e) The actions required by this AD shall be done in accordance 
with the following   R-R service bulletin:

------------------------------------------------------------------------
            Document No.              Pages   Revision        Date      
------------------------------------------------------------------------
Mandatory SB No. Sp72-1034.........      1-3         1  May 1990.       
Total pages: 3.                                                         
------------------------------------------------------------------------

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 be inspected 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.
    (f) This amendment becomes effective on January 6, 1995.

    Issued in Burlington, Massachusetts, on November 9, 1994.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 94-28378 Filed 12-06-94; 8:45 am]
BILLING CODE 4910-13-P