[Federal Register Volume 60, Number 39 (Tuesday, February 28, 1995)]
[Rules and Regulations]
[Pages 10803-10805]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-2693]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 93-ANE-81; Amendment 39-9091; AD 94-25-07]
Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment supersedes an existing telegraphic
airworthiness directive (AD), applicable to Pratt & Whitney (PW) JT8D
series turbofan engines, that currently requires repetitive ultrasonic
inspections of a combustion chamber outer case (CCOC) weld, but also
allows visual inspection or fluorescent magnetic penetrant inspection
(FMPI) of certain CCOC's under specified conditions. This amendment
allows ultrasonic inspections only. This amendment is prompted by the
greater availability of ultrasonic inspection equipment, which provides
a more definitive means of discovering cracks than either visual
inspections or FMPI. The actions specified by this AD are intended to
prevent rupture of the CCOC, which could result in fire, engine cowl
release, or aircraft damage.
DATES: Effective March 30, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 30, 1995.
ADDRESSES: The service information referenced in this AD may be
obtained from Pratt & Whitney, 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 01803-5299; or at the Office
of the Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: Mark A. Rumizen, Aerospace Engineer,
Engine 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: On March 1, 1989, the Federal Aviation
Administration (FAA) issued telegraphic airworthiness directive (AD)
T89-05-52, applicable to Pratt & Whitney (PW) JT8D series turbofan
engines, which requires repetitive ultrasonic inspections for cracks in
the combustion chamber outer case (CCOC). In addition, that telegraphic
AD allowed operators who did not have ultrasonic inspection capability
to perform visual inspections and fluorescent magnetic penetrant
inspections (FMPI) of CCOC's. That action was prompted by reports of
two CCOC's, both part number (P/N) 796761, which were found in service
with severe cracking and distress at the weld which joins the forward
case detail to the rear flange detail. These cracks initiated from an
area of incomplete weld created during the manufacturing process and
were not detected during the final inspection process. Another CCOC, P/
N 806675, is manufactured using a similar process and has the same
potential for incomplete welds, but to date have not been found
cracked. That condition, if not corrected, could result in rupture of
the CCOC, which could result in fire, engine cowl release, or aircraft
damage.
Since the issuance of that telegraphic AD, the FAA has received
reports that most operators now have the capability to perform
ultrasonic inspections, which provides a more definitive means of
discovering cracks than either visual inspections or FMPI. In
telegraphic AD T89-05-52, reinspection of all CCOC's is required,
including reinspection of those CCOC's that exhibited minimal
ultrasonic indications during initial inspection. The FAA has
determined analytically that CCOC's that exhibit maximum signal
amplitudes of less than 40 percent are not life limited at the defined
weld area. Therefore, CCOC's that meet this signal criteria for two
consecutive ultrasonic inspections may be marked with a new P/N,
provided the second ultrasonic inspection is accomplished at least
2,500 cycles in service (CIS) after the first inspection and the second
inspection is performed in accordance with Appendix C of PW Alert
Service Bulletin (ASB) No. 5842, Revision 3, dated October 10, 1990.
Finally, the FAA has determined that certain CCOC's, P/N 806675,
were ultrasonically inspected by PW during the manufacturing process,
and therefore do not need to be inspected again until they are
accessible in the shop.
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) by superseding telegraphic AD T89-05-52 was published in
the Federal Register on January 27, 1994 (59 FR 3797). That action
proposed to require repetitive ultrasonic inspections of CCOC's for
cracks. The proposed AD would also allow CCOC's that meet certain
signal criteria for two consecutive ultrasonic inspections to be marked
with a new P/N. Once remarked, those CCOC's would not need to meet the
repetitive ultrasonic inspection requirements of this AD. Finally, the
proposed AD would require ultrasonic inspections on certain CCOC's, P/N
806675, identified by serial number, that were ultrasonically inspected
by PW during the manufacturing process, when they are accessible in the
shop.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Two commenters state that operators should be exempt from the
initial 10 days or 75 cycles in service (CIS) after the effective date
of this AD, whichever occurs later, ultrasonic inspection if they have
already accomplished the inspection in accordance with telegraphic AD
T89-05-52. The FAA concurs and paragraphs (a) and (b) of the compliance
section of this final rule have been revised in accordance with this
comment.
Three commenters state that they agree with eliminating visual
inspections and only allowing [[Page 10804]] ultrasonic inspections.
The FAA concurs.
One commenter states that the proposed rule will have negligible
effect on operations and maintenance. The FAA concurs.
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 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 1,000 engines installed on aircraft of U.S.
registry will be affected by this AD, that it will take approximately 2
work hours per engine to accomplish the required actions, and that the
average labor rate is $55 per work hour. Based on these figures, the
total cost impact of the AD on U.S. operators is estimated to be
$110,000.
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 a new airworthiness
directive, Amendment 39-9091, to read as follows:
94-25-07 Pratt & Whitney: Amendment 39-9091. Docket 93-ANE-81.
Supersedes telegraphic airworthiness directive (AD) T89-05-52.
Applicability: Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7,
-7A, -7B, -9, -9A, -11, -15, -15A, -17, -17A, -17R, and -17AR
turbofan engines, with combustion chamber outer case (CCOC), Part
Number (P/N) 796761 or 806675. These engines are installed on but
not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9
series aircraft.
Compliance: Required as indicated, unless accomplished
previously.
To prevent rupture of the CCOC, which could result in fire,
engine cowl release, or aircraft damage, accomplish the following:
(a) Except for CCOC's cited in paragraph (c) of this
airworthiness directive (AD), ultrasonically inspect CCOC's
installed in engines that have not previously been ultrasonically
inspected in accordance with telegraphic AD T89-05-52 for cracks
within 10 days or 75 cycles in service (CIS) after the effective
date of this AD, whichever occurs later, in accordance with
paragraph 2.A.(3) and Appendix B of PW Alert Service Bulletin (ASB)
No. 5842, Revision 3, dated October 10, 1990.
(b) For CCOC's not installed in engines and not cited in
paragraph (c) of this AD, and that have not previously been
ultrasonically inspected in accordance with telegraphic AD T89-05-
52, ultrasonically inspect for cracks prior to returning the CCOC's
to service in accordance with paragraph 2.A.(5) and Appendix C of PW
ASB No. 5842, Revision 3, dated October 10, 1990.
(c) For CCOC's, P/N 806675, listed by serial number in Table 1
and paragraph 2.A.(10) of PW ASB No. 5842, Revision 3, dated October
10, 1990, accomplish the following:
(1) At the next removal of the CCOC from the engine after the
effective date of this AD, ultrasonically inspect CCOC's for cracks
in accordance with paragraph 2.A.(5) and Appendix C of PW ASB No.
5842, Revision 3, dated October 10, 1990.
(2) Remove from service or reinspect CCOC's in accordance with
paragraphs (d) and (e), respectively, of this AD.
(3) Mark CCOC's with new part numbers in accordance with
paragraphs 2.A.(5)(c) and 2.A.(11) of PW ASB No. 5842, Revision 3,
dated October 10, 1990, that;
(i) have accumulated at least 2,500 CIS since new; and
(ii) exhibit a maximum ultrasonic signal amplitude of less than
40% during the inspection conducted subsequent to 2,500 CIS since
new.
(d) Remove from service and replace with a serviceable part
CCOC's with maximum ultrasonic signal amplitude determined as
follows:
(1) CCOC's with greater than or equal to 360%, prior to further
flight, with no ferry flight permitted in accordance with paragraph
(i) of this AD below.
(2) CCOC's with less than 360%, but greater than or equal to
240%, prior to further flight, with ferry flight permitted, in
accordance with paragraph (i) of this AD below.
(e) Thereafter, ultrasonically inspect CCOC's, P/N's 796761 and
806675, for cracks at intervals determined by maximum ultrasonic
signal amplitude, in accordance with paragraph 2.A.(3) and Appendix
B of PW ASB No. 5842, Revision 3, dated October 10, 1990, for
installed CCOC's; or paragraph 2.A.(5) and Appendix C of PW ASB No.
5842, Revision 3, dated October 10, 1990, for uninstalled CCOC's; as
applicable, as follows:
(1) For those CCOC's that meet the criteria described in
paragraph (d) of this AD, remove from service and replace with a
serviceable part.
(2) For those CCOC's with less than 240%, but greater than or
equal to 100%, at intervals of 1,000 CIS since last inspection.
(3) For those CCOC's with less than 100%, but greater than or
equal to 40%, at intervals of 2,500 CIS since last inspection.
(4) For those CCOC's with less than 40%, inspect at the next
removal of the CCOC from the engine since last inspection.
(f) Mark CCOC's with new P/N's, in accordance with paragraphs
2.A.(5)(c) and 2.A.(11) of PW ASB No. 5842, Revision 3, dated
October 10, 1990, that meet the following criteria:
(1) At least two consecutive ultrasonic inspections have been
performed on the CCOC; and
(2) The second inspection was performed in accordance with
paragraph (b) of this AD; and
(3) Have accumulated at least 2,500 CIS since the first
ultrasonic inspection; and
(4) That exhibit a maximum ultrasonic signal amplitude of less
than 40% in both inspections.
(g) Remarking of CCOC's with a new P/N in accordance with
paragraph (f) of this AD constitutes terminating action to the
inspection requirements of this AD.
(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 method 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
Secs. 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.
[[Page 10805]]
(j) The actions required by this AD shall be done in accordance
with the following alert service bulletin:
------------------------------------------------------------------------
Document No. Pages Revision Date
------------------------------------------------------------------------
PW ASB No. 5842...... 1-17 3.............. Oct. 10, 1990.
Appendix A........... 1-2 Original....... May 26, 1989.
Appendix B........... 1-23 3.............. Oct. 10, 1990.
Appendix C........... 1-7 Original....... May 26, 1989.
Total pages: 49.
------------------------------------------------------------------------
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, 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 March 30, 1995.
Issued in Burlington, Massachusetts, on January 26, 1995.
Michael H. Borfitz,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 95-2693 Filed 2-27-95; 8:45 am]
BILLING CODE 4910-13-P
