[Federal Register Volume 60, Number 201 (Wednesday, October 18, 1995)]
[Rules and Regulations]
[Pages 53866-53868]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25034]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 85-ANE-34; Amendment 39-9385; AD 86-09-02 R2]
Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan
Engines
agency: Federal Aviation Administration, DOT.
action: Final rule.
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summary: This amendment revises an existing airworthiness directive
(AD), applicable to Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7, -
7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan
engines, that currently requires inspections to detect cracks in the
combustion chambers. This amendment relaxes the current removal
criteria for cracks in the combustion chamber 2-3 liner seam joint,
which will allow additional revenue service for combustion chambers
with certain 2-3 liner seam joint cracks beyond the limits of AD 86-09-
02 R1. This amendment also includes a simplified compliance section and
references the latest revision level of PW Alert Service Bulletin No.
5639. The actions specified by this AD are intended to prevent
uncontained combustion chamber outer case failure due to cracking and
distress of combustion chambers.
dates: Effective November 17, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 17, 1995.
addresses: The service information referenced in this AD may be
obtained from Pratt & Whitney, Publications Department, M/S 132-30, 400
Main St, East Hartford, CT 06108. 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; or at the Office of the Federal Register, 800 North
Capitol Street, NW., 7th Floor, suite 700, Washington, DC.
for further information contact: Mark A. Rumizen, Aerospace Engineer,
Aircraft Certification Office, FAA, Engine and Propeller Directorate,
12 New England Executive Park, Burlington, MA 01803-5299; telephone
(617) 238-7137, fax (617) 238-7199.
supplementary information: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by revising AD 86-09-02 R1,
Amendment 39-5372 (51 FR 28807, August 12, 1986), which is applicable
to certain Pratt & Whitney (PW) JT8D series turbofan engines, was
published in the Federal Register on August 1, 1989 (54 FR 31693). The
action proposed to allow additional revenue service for combustion
chambers with certain 2-3 liner seam joint cracks in excess of 8
inches.
Since issuing AD 86-09-02 R1, the FAA has received reports that
several operators have experienced scheduling difficulties caused by
immediate engine removal due to circumferential cracking in the 2-3
liner seam joint. The FAA has determined by field service experience
and engine test data that the removal criteria for circumferential
cracking in the 2-3 liner seam joint can be relaxed. In addition, the
FAA has determined that a simplified compliance section (relative to
the NPRM), and the latest revision of the associated PW Alert Service
Bulletin (ASB) can now be incorporated.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due
[[Page 53867]]
consideration has been given to the one comment received.
The commenter states unanimous support to relax the current removal
criteria for cracks in the combustion chamber 2-3 liner seam joint.
Since the issuance of the NPRM, PW has introduced new low emission
combustion chamber assemblies. The FAA has determined that this AD is
not applicable to engines with these new low emission combustion
chamber assemblies installed.
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the publication
interest require the adoption of the rule with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
The FAA estimates that 7,120 engines installed on aircraft of U.S.
registry will be affected by this AD, and that this revised amendment
adds no additional costs.
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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-5372 (51 FR
28807, August 12, 1986) and by adding a new airworthiness directive,
Amendment 39-9385, to read as follows:
86-09-02 R2 Pratt & Whitney: Amendment 39-9385. Docket 85-ANE-34.
Revises AD 86-09-02 R1, Amendment 39-5372.
Applicability: Pratt & Whitney (PW) JT8D-1, -1A, -1B, -7, -7A, -
7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR turbofan
engines that do not have low emission combustion chamber assemblies,
Part Number (P/N) 5001958-02, -022, and 5001959-02, -022 installed.
These engines are installed on but not limited to Boeing 727, 737,
and McDonnell Douglas DC-9 series aircraft.
Note: This airworthiness directive (AD) applies to each engine
identified in the preceding applicability provision, regardless of
whether it has been modified, altered, or repaired in the area
subject to the requirements of this AD. For engines that have been
modified, altered, or repaired so that the performance of the
requirements of this AD is affected, the owner/operator must use the
authority provided in paragraph (h) to request approval from the
Federal Aviation Administration (FAA). This approval may address
either no action, if the current configuration eliminates the unsafe
condition, or different actions necessary to address the unsafe
condition described in this AD. Such a request should include an
assessment of the effect of the changed configuration on the unsafe
condition addressed by this AD. In no case does the presence of any
modification, alteration, or repair remove any engine from the
applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
(a) Perform an initial borescope, visual, or radiographic
inspection of the combustion chamber liners for cracking or other
types of distress in accordance with the inspection procedures of
paragraph 2.C.(1) and (2), and Table 1 or 1A, and the inspection
techniques of paragraph B, whichever is applicable, of PW Alert
Service Bulletin (ASB) No. 5639, Revision 10, dated July 7, 1995.
Determine reinspection interval or engine removal requirements in
accordance with paragraph 2.C.(3), (4), (5), or (6), whichever is
applicable, of PW ASB No. 5639, Revision 10, dated July 7, 1995.
(b) Reinspect combustion chamber liners for cracking or other
types of distress in accordance with the inspection procedures of
paragraph 2.C.(3) through (7), and the inspection techniques of
paragraph B, whichever is applicable, of PW ASB No. 5639, Revision
10, dated July 7, 1995, as follows:
(1) For liners initially inspected by borescope or visual means,
reinspect in accordance with Table 2 of PW ASB No. 5639, Revision
10, dated July 7, 1995.
(2) For liners initially inspected by radiographic means,
reinspect in accordance with Table 3 of PW ASB No. 5639, Revision
10, dated July 7, 1995.
(3) Determine reinspection interval or engine removal
requirements in accordance with paragraph 2.C.(3), (4), (5), or (6)
whichever is applicable, of PW ASB No. 5639, Revision 10, dated July
7, 1995.
(c) For liners removed from service in accordance with
paragraphs (a) or (b) of this airworthiness directive (AD), scrap or
repair in accordance with paragraph 2.D of PW ASB No. 5639, Revision
10, dated July 7, 1995.
(d) For the purpose of this AD, an engine condition monitoring
(ECM) program is defined as described in Appendix A of PW ASB No.
5639, Revision 10, dated July 7, 1995, of FAA-approved equivalent.
Should stable cruise data be unavailable for a period exceeding 48
hours (2 calendar days), 12 cycles in service (CIS), or 14 hours
time in service (TIS), whichever occurs later; and should the
combustion chambers be beyond the non-ECM inspection category hour
or cycles limit, the chambers must be inspected within the next 10
CIS. In the event that stable cruise data again becomes available
prior to the expiration of the 10 CIS limit, return to the ECM
inspection category is permitted if the following conditions are
met:
(1) The period during which stable cruise data is unavailable
does not include any one period of data loss that exceeds 72 hours
(3 calendar days), and;
(2) One stable cruise point is recorded for each day that stable
cruise data were unavailable, and that the rate of data acquisition
not exceed one data point per cycle, and;
(3) No maintenance was accomplished on the fuel flow, exhaust
gas temperature (EGT), or N1/N2 rotor speed engine instrumentation,
and;
(4) The stable cruise data recorded in accordance with paragraph
(d)(2) of this AD shall be processed by the ECM program and
evaluated by a qualified analyst to confirm that no significant
parameter shifts have occurred.
(e) The radiographic inspection techniques referenced in
telegraphic AD T85-17-51 R1 as an approved alternative method of
compliance to that telegraphic AD is not considered an alternative
method of compliance with this AD.
(f) Combustion chambers that are removed from service
prematurely, inspected in accordance with this AD, and that do not
require repair, may be returned to service to continue their run to
the appropriate initial inspection threshold or the applicable
repetitive inspection interval, whichever is greater.
(g) Magnesium zirconate heat resistant coating must be applied
in accordance with the PW JT8D Restructured Engine Manual, Part
Number 481762, Chapter 72-41-14,
[[Page 53868]]
Repair Number 28, or FAA-approved equivalent. To meet the requirement
for magnesium zirconate in a given combustion chamber category, the
coating must have been completely renewed on at least the 2 through
5 liners at that repair rather than locally patched.
Note: PW All Operators Wire Number JT8D/72-41/PSE:JKS: 5-8-23-1,
dated August 23, 1985, and Flight Operations Engineering Report
Number RFT5-8-30-1, dated August 30, 1985, contain further
information relevant to combustion chamber distress and the symptoms
that manifest themselves as a result of excessive combustion chamber
cracking and misalignment.
(h) An alternative method of compliance or adjustment of the
initial 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
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 AD, 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, replacement, and repair, shall be done in
accordance with the following alert service bulletin:
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Document No. Pages Revision Date
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PW ASB No. 5639............... 1 and 2 10 July 7, 1995.
3 1 March 21, 1986.
4 10 July 7, 1995.
5 2 January 16, 1987.
6-26 10 July 7, 1995.
Appendix...................... 27-29 10 July 7, 1995.
30 Blank
31-64 10 July 7, 1995.
Total pages: 64.
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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 Pratt & Whitney, Publications
Department, M/S 132-30, 400 Main St, East Hartford, CT 06108. 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.
(k) This amendment becomes effective on November 17, 1995.
Issued in Burlington, Massachusetts, on September 27, 1995.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 95-25034 Filed 10-17-95; 8:45 am]
BILLING CODE 4910-13-M
