[Federal Register Volume 67, Number 178 (Friday, September 13, 2002)]
[Proposed Rules]
[Pages 57986-57989]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-23290]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-44-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The Federal Aviation Administration (FAA) proposes to revise 
an existing airworthiness directive (AD), applicable to Pratt & Whitney 
PW4164, PW4168, and PW4168A series turbofan engines. That AD currently 
requires initial and repetitive torque checks for loose or broken front 
pylon mount bolts made from INCO 718 material and MP159 material. That 
AD also requires initial and repetitive visual inspections of the 
primary mount thrust load path. This proposal extends the cycles 
accumulated before performing the initial inspection, and reduces the 
frequency of repetitive inspections for MP159 material bolts, and adds 
a terminating action to the primary mount thrust load path inspections 
by introducing a new increased durability engine mount forward mount 
bearing housing. This proposed revision is prompted by component 
testing to assess the low cycle fatigue (LCF) life of the MP159 
material bolts and the development of a new design forward engine mount 
bearing housing that meets the 8,000 flight cycle design intent for 
inspection. The actions specified by the proposed 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: Comments must be received by November 12, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 57987]]

Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 97-ANE-44-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected].'' 
Comments sent via the Internet must contain the docket number in the 
subject line.
    The service information referenced in the proposed rule 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, by appointment, at the Federal Aviation Administration (FAA), 
New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-ANE-44-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 97-ANE-44-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On August 1, 2000, the FAA issued AD 2000-16-02, Amendment 39-11856 
(65 FR 49730, August 15, 2000), applicable to Pratt & Whitney PW4164, 
PW4168, and PW4168A series turbofan engines. That AD requires initial 
and repetitive torque checks for loose or broken front pylon mount 
bolts made from INCO 718 material and MP159 material. That AD also 
requires initial and repetitive visual inspections of the primary mount 
thrust load path. That condition, if not corrected, could result in an 
engine separating from the airplane.
    Since AD 2000-16-02 was issued, Pratt & Whitney has determined that 
the cycles accumulated before performing the intitial inspections 
should be extended from 1,250 cycles to 4,100 cycles and that the 1,250 
cycle maximum inspection interval specified in paragraph (c) of that AD 
should be increased to a 4,350 cycle maximum inspection interval for 
MP159 material bolts. In addition, Pratt & Whitney is introducing a new 
forward mount bearing housing (monoball housing) which constitutes 
terminating action for repetitive inspections. This improved housing 
will eliminate the 1,250 cycle maximum inspection interval of the 
forward engine mount primary thrust load path, presently being 
performed in accordance with Alert Service Bulletin (ASB) PW4G-100-A71-
18, allowing the improved housing to achieve the 8,000 flight cycle 
inspection goal. This proposed revision is prompted by component 
testing that assessed the low cycle fatigue (LCF) life of MP159 
material bolts, and the development of a new design forward engine 
mount bearing housing that meets the 8,000 flight cycle design intent 
for inspection. The FAA reviewed this analysis and agrees with it.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of the 
following Pratt & Whitney alert service bulletins (ASB's) and service 
bulletin (SB):
    [sbull] ASB PW4G-100-A71-9, Revision 1, dated November 24, 1997, 
that describes the repetitive inspection procedures for the forward 
mount pylon bolts and adds a note to Part B of the Accomplishment 
Instructions.
    [sbull] ASB PW4G-100-A71-20, Revision 1, dated January 15, 2002, 
that describes the repetitive inspection procedures for engines with 
the MP159 material forward mount pylon bolts, part number (P/N) 51U615, 
to verify the integrity of the bolts to identify a bolt-out condition. 
In addition, the 1,250 maximum cycle inspection interval is increased 
to 4,350 cycles maximum.
    [sbull] ASB PW4G-100-A71-18, Revision 2, dated January 15, 2002, 
that describes the procedures for visually inspecting the primary mount 
thrust load path; and adds Pratt & Whitney ASB PW4G-100-A71-22, dated 
January 15, 2002, to the references section. ASB PW4G-100-71-18 also 
lists ASB PW4G-100-71-22, dated January 15, 2002, as an alternate 
method of compliance for the periodic inspection of the primary thrust 
load path components.
    [sbull] SB PW4G-100-A71-22, dated January 15, 2002, that introduces 
a new increased durability forward mount bearing housing (monoball 
housing), P/N 52U420.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Pratt & Whitney PW4164, PW4168, and PW4168A 
series turbofan engines of this same type design, the proposed AD would 
revise AD 2000-16-02 to:
    [sbull] Require extension of the cycles accumulated for performing 
initial inspection.
    [sbull] Require an extension of the frequency of performing 
repetitive inspections for MP159 material bolts.
    [sbull] Add a terminating action to the primary mount thrust load 
path inspections by introducing a new increased durability engine mount 
forward mount bearing housing.

Economic Analysis

    There are approximately 226 engines of the affected design in the 
worldwide fleet. The FAA estimates that 21 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD. The 
FAA also estimates that it would take approximately 3 work hours per 
engine to perform the proposed actions, and that the average labor rate 
is $60 per work hour. Required parts would cost approximately $19,000 
per engine. Based on these figures, the total cost of the proposed AD 
to U.S. operators is estimated to be $402,780.

[[Page 57988]]

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it would 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 proposed rule.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 39-11856 (65 FR 
49730, August 15, 2000), and by adding a new airworthiness directive, 
to read as follows:

Pratt & Whitney: Docket No. 97-ANE-44-AD. Revises AD 2000-16-02, 
Amendment 39-11856.

Applicability

    This airworthiness directive (AD) is applicable to Pratt & 
Whitney PW4164, PW4168, and PW4168A series turbofan engines, with 
front pylon mount bolts, part numbers (P/N's) 54T670 or 51U615, 
installed. These engines are installed on but not limited to Airbus 
Industrie A330 series airplanes.

    Note 1: 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 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

    Compliance with this AD is required as indicated, unless already 
done.
    To prevent front pylon mount bolt and primary mount thrust load 
path failure, which could result in engine separation from the 
airplane, do 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 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 ASB:
    (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 of not less 
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 less 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 ASB:
    (i) Perform an initial torque check within 250 CIS after the 
effective date of this AD, or at the next engine removal for any 
cause, whichever occurs first.
    (ii) Thereafter, perform torque checks at intervals of not less 
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 
ASB:
    (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 of not less 
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 ASB, 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 Pratt & Whitney ASB PW4G-100-A71-20, Revision 1, 
dated January 15, 2002, as follows:
    (1) For front pylon mount bolts with less than 4,100 CSN on the 
effective date of this AD, perform the initial torque inspection at 
the earlier of the following:
    (i) Before accumulating 4,350 CSN; or
    (ii) The next engine removal for any cause.
    (2) For front pylon mount bolts with 4,100 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 to 
exceed 4,350 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 2, 
dated January 15, 2002, 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 of not 
less 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.

Terminating Action

    Replacement of the forward engine mount housing, part number, P/
N 59T794 or P/N 54T659 with P/N 52U420 in accordance with Service 
Bulletin (SB) PW 4G-100-71-22, dated January 15, 2002, constitutes

[[Page 57989]]

terminating action to the inspection requirements of paragraph (d) 
of this AD.

Alternative Methods 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 must submit their request 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 
Sec. Sec.  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 done.

    Issued in Burlington, Massachusetts, on September 5, 2002.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-23290 Filed 9-12-02; 8:45 am]
BILLING CODE 4910-13-P