[Federal Register Volume 62, Number 182 (Friday, September 19, 1997)]
[Rules and Regulations]
[Pages 49133-49135]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24796]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-ANE-32; Amendment 39-10133; AD 97-19-12]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Pratt & Whitney JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A,
-11, -15, -17, and -17R series turbofan engines, that requires initial
and repetitive fluorescent penetrant and eddy current inspections of
4th stage low pressure turbine (LPT) hubs for cracks, and, if
necessary, replacement with serviceable parts. This amendment
[[Page 49134]]
is prompted by a report of an uncontained 4th stage LPT blade release.
The actions specified by this AD are intended to prevent a 4th stage
LPT blade release due to hub cracking, which can result in an
uncontained engine failure and damage to the aircraft.
DATES: Effective November 18, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 18, 1997.
ADDRESSES: The service information referenced in this AD may be
obtained from Pratt & Whitney, Publication Department, Supervisor
Technical Publications Distribution, M/S 132-30, 400 Main St., East
Hartford, CT 06108; telephone (860) 565-7700, fax (860) 565-4503. 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., suite 700, Washington,
DC.
FOR FURTHER INFORMATION CONTACT: Christopher Spinney, Aerospace
Engineer, Engine Certification Office, FAA, Engine and Propeller
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299;
telephone (781) 238-7175, fax (781) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to Pratt & Whitney JT8D-1, -1A, -1B,
-7, -7A, -7B, -9, -9A, -11, -15, -17, and -17R series turbofan engines
was published in the Federal Register on January 9, 1997 (62 FR 1299).
That action proposed to require initial and repetitive fluorescent
penetrant inspections (FPI) and eddy current inspections (ECI) of
affected 4th stage low pressure turbine (LPT) hubs for cracks, and, if
necessary, replacement with serviceable parts.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Four commenters support the rule as proposed.
One commenter states that the inspection should be performed in
less than 5,900 cycles in service (CIS), as that was the number of CIS
between the last FPI and the uncontained event that prompted this AD.
The FAA does not concur. The FAA has evaluated the data and risk
management plan supplied by PW that includes risk analysis, crack
growth analysis, and field experience for the 4th stage LPT hubs. That
data supports the FAA conclusion that the unsafe condition is an
uncontained release of an LPT blade. The FAA concludes the loads
introduced by the cracking of the 4th stage hub are not sufficient to
result in an uncontained release of the entire 4th stage hub. Further,
the analyses support the risk management plan, which includes a
focused, ultra high sensitivity FPI and ECI at the next piece part
exposure. The FAA has also concluded that the unsafe condition
resulting from an uncontained blade failure can be mitigated by a
reduced compliance time for installing LPT containment hardware on
engines in which certain 4th stage LPT hubs are installed. The revised
compliance requirement is described in AD 97-19-14.
After careful review of the available data, including the comments
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 381 engines installed on aircraft of U.S.
registry will be affected by this AD, that it will take approximately 6
work hours per engine to accomplish the required actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
total cost impact of the AD on U.S. operators is estimated to be
$137,160.
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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
97-19-12 Pratt & Whitney: Amendment 39-10133. Docket 96-ANE-32.
Applicability: Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7,
-7A, -7B, 9, -9A, -11, -15, -17, and -17R turbofan engines, with 4th
stage low pressure turbine (LPT) hubs identified by serial number
(S/N) in Table A of PW Alert Service Bulletin (ASB) No. A6274,
Revision 1, dated December 9, 1996. These engines are installed on
but not limited to Boeing 727 and 737 series, and McDonnell Douglas
DC-9 series aircraft.
Note 1: 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 request
approval for an alternative method of compliance in accordance with
paragraph (b) of this AD. The request should include an assessment
of the effect of the modification, alteration, or repair on the
unsafe condition addressed by this AD; and, if the unsafe condition
has not been eliminated, the request should include specific
proposed actions to address it.
Compliance: Required as indicated, unless accomplished
previously.
To prevent 4th stage LPT blade failure due to hub cracking,
which can result in an uncontained engine failure and damage to the
aircraft, accomplish the following:
(a) Perform fluorescent penetrant inspection (FPI) and eddy
current inspection (ECI) of affected 4th stage LPT hubs for cracks,
in accordance with Paragraph 2A of PW ASB No. A6274, Revision 1,
dated December 9, 1996, as follows:
(1) Inspect at the next time after the effective date of this AD
that the hub is removed from the module and has been debladed.
(2) Thereafter, inspect each time the hub is removed from the
module and has been debladed.
[[Page 49135]]
(3) Remove from service any cracked 4th stage LPT hub and
replace with a serviceable part.
(b) 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.
Operators shall forward their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(c) 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.
(d) The actions required by this AD shall be done in accordance
with the following PW ASB:
------------------------------------------------------------------------
Document No. Pages Revision Date
------------------------------------------------------------------------
A6274........................ 1-23 1 December 9, 1996.
------------------------------------------------------------------------
Total Pages: 23.
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, Publication Department,
Supervisor Technical Publications Distribution,
M/S 132-30, 400 Main St., East Hartford, CT 06108; telephone (860) 565-
7700, fax (860) 565-4503. 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.
(e) This amendment becomes effective on November 18, 1997.
Issued in Burlington, Massachusetts, on September 10, 1997.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 97-24796 Filed 9-18-97; 8:45 am]
BILLING CODE 4910-13-U
