[Federal Register Volume 60, Number 78 (Monday, April 24, 1995)]
[Rules and Regulations]
[Pages 20019-20021]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-9471]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-ANE-04; Amendment 39-9204; AD 95-08-15]


Airworthiness Directives; Pratt & Whitney JT8D Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to Pratt & Whitney (PW) JT8D series turbofan engines. 
This action requires a one-time borescope inspection of certain 
combustion chamber outer cases (CCOC) installed only on McDonnell 
Douglas DC-9 series and Boeing 737 series aircraft, and an ultrasonic 
inspection of all affected CCOC's at every accessibility. This 
amendment is prompted by reports of two CCOC ruptures in service and of 
two CCOC's discovered during maintenance with intergranular cracks. The 
actions specified in this AD are intended to prevent CCOC rupture, 
which can result in an uncontained engine failure and damage to the 
aircraft.

DATES: Effective May 9, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 9, 1995.
    Comments for inclusion in the Rules Docket must be received on or 
before June 23, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 95-ANE-04, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    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 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: 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: The Federal Aviation Administration (FAA) 
has received reports of two uncontained engine failures on Pratt & 
Whitney (PW) JT8D series turbofan engines. Investigation revealed that 
the engine failures were due to combustion chamber outer case (CCOC) 
ruptures that exhibited intergranular cracking. The CCOC ruptures 
resulted from the low cycle fatigue (LCF) propagation of the 
intergranular crack. In addition, intergranular cracking on two other 
CCOC's was discovered during in-shop maintenance. The FAA has 
determined that intergranular cracks may develop from an initiation 
site on the case during assembly of the CCOC to the high pressure 
turbine (HPT) case, or during engine operation in which an impact load 
is imposed on the CCOC. During subsequent engine operation, the crack 
can then propagate to failure due to normal LCF loads. Analysis of 
operating experience relative to CCOC ruptures indicated that only 
engines installed on McDonnell Douglas DC-9 series and Boeing 737 
series aircraft have a significant risk of CCOC rupture, whereas 
engines installed on other aircraft have been statistically proven to 
have less risk of CCOC rupture. Therefore, the FAA has determined that 
a borescope inspection of CCOC's installed only on McDonnell Douglas 
DC-9 series and Boeing 737 series aircraft is required to meet safety 
of flight criteria. However, the FAA has determined that an ultrasonic 
inspection of all affected CCOC's during in-shop maintenance is also 
required, regardless of intended aircraft installation, to meet safety 
of flight criteria. This condition, if not corrected, could result in 
CCOC rupture, which can result in an uncontained engine failure and 
damage to the aircraft.
    The FAA has reviewed and approved the technical contents of PW 
Alert Service Bulletin (ASB) No. A6202, dated February 20, 1995, that 
describes procedures for a one-time borescope inspection of certain 
CCOC's installed [[Page 20020]] only on McDonnell Douglas DC-9 series 
and Boeing 737 series aircraft, and an ultrasonic inspection of all 
affected CCOC's at every accessibility when the ``J'' and ``K'' flanges 
are separated and the outer split fan ducts are removed.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other PW JT8D series turbofan engines of the same 
type design, this AD is being issued to prevent CCOC rupture, which can 
result in an uncontained engine failure and damage to the aircraft. 
This AD requires a one-time borescope inspection of certain CCOC's 
installed only on McDonnell Douglas DC-9 series and Boeing 737 series 
aircraft, and an ultrasonic inspection of all affected CCOC's at every 
accessibility when the ``J'' and ``K'' flanges are separated and the 
outer split fan ducts are removed. However, performing the ultrasonic 
inspection in the shop or on-wing is an acceptable alternative to 
performing the borescope inspection. The actions are required to be 
accomplished in accordance with the ASB described previously.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-ANE-04.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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:

95-08-15  Pratt & Whitney: Amendment 39-9204. Docket 95-ANE-04.

    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 cases (CCOC) Part 
Numbers (P/N) 490547, 542155, 616315, 728829, 728829-001, 730413, 
730413-001, 730414, 730414-001, 767197, 767279, and 767279-001. 
These engines are installed on but not limited to Boeing 737 series 
and 727 series, and McDonnell Douglas DC-9 series aircraft.

    Note: This 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 (f) to 
request approval from the FAA. This approval may address either no 
action, if the current configuration eliminates the unsafe 
condition, or different action 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.
    To prevent CCOC rupture, which can result in an uncontained 
engine failure and damage to the aircraft, accomplish the following:
    (a) For engines installed on McDonnell Douglas DC-9 series 
aircraft, perform the following:
    (1) Perform a borescope inspection of the CCOC for cracking 
within 1,000 cycles in service (CIS) after the effective date of 
this airworthiness directive (AD), in accordance with Section 2.A of 
PW Alert Service Bulletin (ASB) No. A6202, dated February 20, 1995.
    (2) Remove from service CCOC's that exhibit cracking in 
accordance with Section 2.A of PW ASB No. A6202, dated February 20, 
1995.
    (b) For engines installed on Boeing 737 series aircraft, perform 
the following:
    (1) Perform a borescope inspection of the CCOC for cracking 
within 1,500 CIS after the effective date of this AD, in accordance 
with Section 2.A of PW ASB No. A6202, dated February 20, 1995.
    (2) Remove from service CCOC's that exhibit cracking in 
accordance with section 2.A of PW ASB No. A6202, dated February 20, 
1995.
    (c) At every accessibility of the CCOC after the effective date 
of this AD, perform the following:
    (1) Prior to reassembly of the outer split fan ducts, perform an 
ultrasonic inspection for cracking in accordance with Section 2.B of 
[[Page 20021]] PW ASB No. A6202, dated February 20, 1995.

    (2) Remove from service CCOC's that exhibit cracking in 
accordance with Section 2.B of PW ASB No. A6202, dated February 20, 
1995.

    (d) Compliance with paragraph (c) of this AD is an acceptable 
alternative to performing the borescope inspection required by 
paragraph (a) or (b) of this AD, as applicable.

    (e) For the purpose of this AD, accessibility of the CCOC is 
defined as separation of the ``J'' and ``K'' flanges and removal of 
the outer split fan ducts.

    (f) 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 methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (g) 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.

    (h) The inspections of the CCOC shall be done in accordance with 
the following service document:


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               Document No.                 Pages           Date        
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PW ASB No. A6202.........................     1-11  Feb. 20, 1995.      
  Total pages: 11.                                                      
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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.

    (i) This amendment becomes effective on May 9, 1995.

    Issued in Burlington, Massachusetts, on April 11, 1995.

James C. Jones,

Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.

[FR Doc. 95-9471 Filed 4-21-95; 8:45 am]

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