[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]



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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.

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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:

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     Document No.         Pages        Revision             Date        
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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.                                                      
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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, 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]
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