[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]
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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.
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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(AD) T89-02-52, which superseded Telegraphic AD T88-22-51 (AD),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:
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Document No. Pages Revision Date
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Mandatory SB No. Sp72-1034......... 1-3 1 May 1990.
Total pages: 3.
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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]
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