[Federal Register Volume 65, Number 158 (Tuesday, August 15, 2000)]
[Rules and Regulations]
[Pages 49730-49732]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-20241]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-44-AD; Amendment 39-11856; AD 2000-16-02]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney PW4164, PW4168, and 
PW4168A Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Pratt & Whitney PW4164, PW4168, and PW4168A series 
turbofan engines. The current AD requires initial and repetitive torque 
checks for loose or broken bolts used to secure the engine to the 
airplane made from INCO 718 material (front pylon mount bolts). The 
current AD also requires the replacement of the bolts, if necessary, 
with new bolts, and establishes a new cyclic life limit for the front 
pylon mount bolt. This amendment adds requirements for initial and 
repetitive torque checks of front pylon mount bolts made from a new 
material, MP159, and initial and repetitive visual inspections of the 
primary mount thrust load path. This amendment is prompted by the use 
of front pylon mount bolts made from MP159 material and fatigue testing 
that shows that the forward engine mount bearing housings have 
insufficient fatigue life expectancy.
    The actions specified by this AD are intended to prevent front 
pylon mount bolt and primary mount thrust load path failure, which 
could result in an engine separating from the airplane.

DATES: Effective date October 16, 2000. The incorporation by reference 
of certain publications listed in the rule is approved by the Director 
of the Federal Register as of October 16, 2000.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; 
telephone (860) 565-8860, fax (860) 565-4503. This information may be 
examined at the Federal Aviation Administration (FAA), New England 
Region, Office of the Regional 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: Tara Goodman, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7130, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD-98-04-14, 
Amendment 39-10326 (63 FR 9730, February 26, 1998), applicable to Pratt 
& Whitney (PW) PW4164, PW4168, and PW4168A series turbofan engines was 
published in the Federal Register on March 24, 2000 (65 FR 15878). That 
action proposed to require, in addition to the requirements of the 
current AD, initial and repetitive torque checks of front pylon mount 
bolts made from MP159 material, and initial and repetitive visual 
inspections of the primary mount thrust load path.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Changes to the Required Actions

    One comment suggests wording changes to the required actions in an 
effort to make them similar to the published service bulletins. The 
comment suggests that paragraph (a)(1) be modified to read ``* * *, 
with fewer than 1,000 cycles-since-new (CSN) on the effective date of 
this AD, * * *''.
    The FAA agrees. The proposed initial and reptitive inspections for 
bolts made from INCO 718 material with 1,000 or fewer cycles in service 
(CSN) on the effective date of the AD were added in response to a 
comment received following the publication of the current AD. That 
comment pointed out that bolts with 1,000 or fewer CSN on the effective 
date of that AD have no initial or repetitive inspection requirement. 
Since the current AD address bolts with ``more than 1,000'' CSN, the 
proposal added the younger bolt population by using the term ``1,000 or 
fewer'' CSN. The comment merely asks the FAA to adjust the dividing 
line between those two populations of bolts to conform to the service 
bulletin. Therefore, subparagraph (a)(1) has been changed to read 
``fewer than 1,000'' CSN and the subparagraph that defines the next 
older population of bolts has been changed to read ``1,000 or more'' 
CSN.
    Another comment recommends that subparagraph (a)(1)(ii), which 
reads, ``Within 250 cycles-in-service (CIS) after the effective date of 
this AD,'' be deleted.
    The FAA agrees. For the population of bolts that have fewer than 
1,000 CSN on the effective date of the AD, the initial inspection is 
generally not required until after the bolt reaches 1,000 CSN. The only 
exception would be if the engine were removed for cause.
    Another comment recommends that proposed subparagraph (a)(4)(ii) be 
changed to read ``thereafter, perform torque checks at intervals not 
less than 5,750 or greater than 6,250 CIS since last torque check, not 
to exceed 11,000 CSN.''
    The FAA does not agree. The reinspection interval suggested is 
significantly different than the requirement proposed, which was to 
reinspect not less than 750 CIS or greater than 1,250 CIS since last 
torque check. The reinspection requirements for INCO 718 material bolts 
should be identical with the original AD published February 26, 1998, 
AD 98-04-14. The structure of the wording in the NPRM to supersede was 
inadvertently changed from the structure of the wording of the 
requirements of the original AD.
    Another comment recommends that proposed paragraph (c), requiring 
inspections for bolts made from MP159 material, be revised to separate 
bolts into younger and older populations in the same manner as with 
bolts made from INCO 718 material.
    The FAA agrees and has revised paragraph (c) to reflect two 
populations of bolts, those with fewer than 1,000 CSN on the effective 
date of the AD and those with 1,000 or more CSN on the effective date 
of the AD.
    Another comment recommends that proposed paragraph (d), requiring 
inspections of the primary mount thrust load path, also reflect engines 
with fewer than 1,000 CSN on the effective date of the AD and those 
with 1,000 or more CSN on the effective date of the AD.
    The FAA agrees and has revised paragraph (d) accordingly.
    Lastly, a comment suggests that paragraph (d)(3) be changed to read 
``prior to further flight, inspect and replace mount details in 
accordance with paragraph 4 of the accomplishment

[[Page 49731]]

instructions of the service bulletin, if the visual inspection 
indicates the secondary thrust load path was activated.''
    The FAA agrees in part. The suggested wording is not specific as to 
what constitutes activation of the secondary thrust load path. The 
service bulletin uses the word ``damage'' while the proposed paragraph 
(d)(3) uses the word ``crack'' to be more specific. The FAA does not 
agree that the word ``crack'' should be replaced with the word 
``damaged.'' The FAA agrees, however, that paragraph 4 of the 
accomplishment instructions of the service bulletin should be 
referenced in order to specify the manner in which cracked components 
must be replaced. That change has been made, but with a more specific 
citation to the SB referenced.

Concurrence With the Rule

    Another comment expressed no objection to the proposed rule, as 
there should not be any adverse operational impact.

Other Changes to the Proposed Rule

    A further review of the proposed rule has revealed the need for 
some additional minor changes that neither alter the scope of the rule 
nor change the substance of the required actions. Proposed paragraph 
(a)(2) provides repetitive inspections that were intended to be 
applicable for only those bolts inspected under paragraph (a)(1). 
Therefore, paragraph (a)(1) has been restructured to include both the 
initial and repetitive inspection requirements in a manner similar to 
proposed subparagraphs (a)(3) and (a)(4). Proposed subparagraph (a)(2) 
has been deleted and the remaining subparagraphs renumbered.
    Also, proposed subparagraph (a)(5), which addresses bolts made from 
INCO 718 material that have 8,000 or more CSN on the effective date of 
the AD, has been deleted. The original AD and the NPRM included a 
requirement to accomplish a full system inspection as referenced in the 
Appendix of the SB. This requirement is not necessary because a full 
torque check of the bolts is required at 6,000 CSN and the bolts will 
be retired by 11,000 CSN. The full system inspection is part of the 
normal maintenance requirements for the airplane.

Conclusion

    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.

Economic Impact

    There are approximately 75 engines of the affected design in the 
worldwide fleet. The FAA estimates that 10 engines installed on 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 3 work hours per engine to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $18,832 per engine. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $190,120.

Regulatory Impact

    This rule does not have federalism implications, as defined in 
Executive Order 13132, because it does not have a substantial direct 
effect 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this rule.
    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 removing Amendment 39-10326 (63 FR 
9730, February 26, 1998) and by adding a new airworthiness directive, 
Amendment 39-11856, to read as follows:

2000-16-02  Pratt & Whitney: Amendment 39-11856. Docket 97-ANE-44-
AD. Supersedes AD 98-04-14, Amendment 39-10326.

    Applicability: Pratt & Whitney (PW) PW4164, PW4168, and PW4168A 
series turbofan engines, with front pylon mount bolts, part numbers 
(P/Ns) 54T670 or 51U615, installed. These engines are installed on 
but not limited to Airbus Industrie A330 series airplances.

    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 (e) 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 front pylon mount bolt and primary mount thrust load 
path failure, which could result in engine separation from the 
airplance, accomplish the following:

INCO 718  Material Bolts Torque Checks

    (a) Perform initial and repetitive torque checks of INCO 718 
material front pylon mount bolts, P/N 54T670, and replace, if 
necessary, with new bolts, in accordance with the Accomplishment 
Instructions of Pratt & Whitney (PW) Alert Service Bulletin (ASB) 
No. PW4G-100-A71-9, Revision 1, dated November 24, 1997, as follows:
    (1) For front pylon mount bolts, P/N 54T670, with fewer than 
1,000 cycles-in-service-since-new (CSN) on the effective date of 
this AD, accomplish the following in accordance with Part (A) of the 
Accomplishment Instructions of the SB:
    (i) Perform an initial torque check prior to accumulating 1,250 
CSN or at the next engine removal for cause, whichever occurs first.
    (ii) Thereafter, perform torque checks at intervals not fewer 
than 750 or greater than 1,250 cycles in service (CIS) since last 
torque check, not to exceed 11,000 CSN.
    (2) For front pylon mount bolts, P/N 54T670, with 1,000 or more 
CSN but fewer than 5,750 CSN on the effective date of this AD, 
accomplish the following in accordance with Part (A) of the 
Accomplishment Instructions of the SB:
    (i) Perform an initial torque check within 250 CIS after the 
effective date of this AD, or

[[Page 49732]]

at the next engine removal for any cause, whichever occurs first.
    (ii) Thereafter, perform torque checks at intervals not fewer 
than 750 or greater than 1,250 CIS since last torque check, not to 
exceed 11,000 CSN.
    (3) For front pylon mount bolts, P/N 54T670, with 5,750 or more 
CSN on the effective date of this AD, accomplish the following in 
accordance with Part (B) of the Accomplishment Instructions of the 
SB:
    (i) Perform an initial torque check within 250 CIS after the 
effective date of this AD, or prior to the next engine removal for 
any cause, whichever occurs first.
    (ii) Thereafter, perform torque checks at intervals not fewer 
than 750 or greater than 1,250 CIS since last torque check, not to 
exceed 11,000 CSN.
    (4) Prior to further flight, replace all four bolts in 
accordance with Part (A), Paragraph 1(D) of the Accomplishment 
Instructions of the SB, if any of the bolts are loose or broken.

INCO 718  Material Bolts Life Limit

    (b) This AD establishes a new life limit of 11,000 CSN for front 
pylon mount bolts, P/N 54T670. Except as provided in paragraph (e) 
of this AD, no front pylon mount bolts, P/N 54T670, may exceed this 
new life limit after the effective date of this AD.

MP159  Material Bolts Inspections

    (c) Perform initial and repetitive torque inspections of front 
pylon mount bolts, P/N 51U615, in accordance with the Accomplishment 
Instructions of PW ASB PW4G-100-A71-20, dated December 9, 1999, as 
follows:
    (1) For front pylon mount bolts with fewer than 1,000 CSN on the 
effective date of this AD, perform the initial torque inspection at 
the earlier of the following:
    (i) Before accumulating 1,250 CSN, or
    (ii) The next engine removal for any cause.
    (2) For front pylon mount bolts with 1,000 or more CSN on the 
effective date of this AD, perform the initial torque check at the 
earlier of the following:
    (i) Within 250 CIS after the effective date of this AD, or
    (ii) The next engine removal for any cause.
    (3) Thereafter, perform torque inspections at intervals not 
fewer than 750 or greater than 1,250 CIS since last torque 
inspection.
    (4) Prior to further flight, replace all four bolts, in 
accordance with Paragraph 1(D) of the Accomplishment Instructions of 
the ASB, if any are loose or broken.

Primary Mount Thrust Load Path Inspections

    (d) Perform initial and repetitive visual inspections of the 
primary mount thrust load path, in accordance with the 
Accomplishment Instructions of PW ASB PW4G-100-A71-18, Revision 1, 
dated December 9, 1999, as follows:
    (1) For forward engine mount assemblies with fewer than 1,000 
CSN on the effective date of this AD, perform the initial visual 
inspection at the earlier of the following:
    (i) Before accumulating 1,250 CSN, or
    (ii) The next engine removal for any cause.
    (2) For forward engine mount assemblies with 1,000 or more CSN 
on the effective date of this AD, perform the initial visual 
inspection at the earlier of the following:
    (i) Within 250 CIS after the effective date of this AD, or
    (ii) The next engine removal for any cause.
    (3) Thereafter, perform visual inspections at intervals not 
fewer than 750 or greater than 1,250 CIS since last visual 
inspection.
    (4) Prior to further flight, replace all cracked parts with 
serviceable parts and inspect the primary thrust load path 
components in accordance with Paragraph 4 of the accomplishment 
instructions of the SB.

Alternative Method of Compliance

    (e) 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 (ECO). 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (f) 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 airplane to a location where 
the requirements of this AD can be accomplished.

Incorporation by Reference

    (g) The inspection shall be done in accordance with the 
following PW ASBs:

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             Document No.                 Pages             Revision                         Date
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PW4G-100-A71-9.......................           11  Rev. 1..................  November 24, 1997
PW4G-100-A71-20......................           10  ........................  December 9, 1999
PW4G-100-A71-18......................           12  Rev. 1..................  December 9, 1999
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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; telephone (860) 565-8860, fax (860) 565-4503. 
Copies may be inspected at the FAA, New England Region, Office of 
the Regional 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.

Effective Date

    This amendment becomes effective on October 16, 2000.

    Issued in Burlington, Massachusetts, on August 1, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-20241 Filed 8-14-00; 8:45 am]
BILLING CODE 4910-13-U