[Federal Register: June 26, 2002 (Volume 67, Number 123)]
[Rules and Regulations]               
[Page 42981-42983]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26jn02-1]                         






Rules and Regulations
                                                Federal Register
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[[Page 42981]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-49-AD; Amendment 39-12787; AD 2002-12-15]
RIN 2120-AA64

 
Airworthiness Directives; Pratt & Whitney PW4000 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), that is applicable to Pratt & Whitney PW4000 series turbofan 
engines. That AD requires operators to perform initial and repetitive 
inspections for cracking of high pressure compressor (HPC) front drum 
rotors based on cycle usage. That AD also requires the removal from 
service of any cracked HPC front drum rotors. This amendment clarifies 
inspection requirements for cracking of HPC front drum rotors that have 
fewer than 1,000 cycles-since-new (CSN). This amendment is prompted by 
comments from operators seeking more clarity about the inspection 
requirements of paragraph (a)(1) of that AD. The actions specified by 
this AD are intended to prevent HPC drum rotor failure from cracks that 
could result in an uncontained engine failure and damage to the 
airplane.

DATES: Effective date July 31, 2002. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of July 31, 2002.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney, 400 Main Street, East Hartford, CT 
06108. This information may be examined, by appointment, at the FAA, 
New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA. 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; 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 2001-20-13, 
Amendment 39-12461 (66 FR 52023, October 12, 2001), which is applicable 
to Pratt & Whitney PW4000 series turbofan engines, was published in the 
Federal Register on January 15, 2002 (67 FR 1913). That action proposed 
to clarify inspection requirements for cracking of HPC front drum 
rotors that have fewer than 1,000 cycles-since-new (CSN), in accordance 
with Pratt & Whitney Alert Service Bulletin (ASB) PW4ENG A72-722, dated 
September 29, 2000 and ASB PW4ENG A72-722, Revision 1, dated June 7, 
2001.

Comments

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

Request for Inspection Clarification

    Two commenters state that in proposed paragraph (a), the inspection 
requirements are not clear for HPC front drum rotors with fewer than 
1,000 cycles-since-new (CSN). One of the commenters states that the 
requirements are not clear on how to fulfill the initial inspection for 
HPC front drum rotors with less than 1,000 CSN. The commenter states 
that proposed paragraph (a)(1) refers to an HPC front drum rotor with 
less than 1,000 CSN, but the front drum must have accumulated at least 
1,000 CSN before an initial inspection can be carried out. Therefore, 
it is not possible to fulfill the AD. The commenter suggests changing 
the wording of paragraph (a)(1) to say that HPC front drum rotors must 
have accumulated at least 1,000 CSN before an inspection can be carried 
out as an initial inspection.
    The FAA does not agree. Proposed paragraph (a)(1) states that HPC 
front drum rotors may have fewer than 1,000 cycles-since-new on the 
effective date of the AD, and further states that after the front drum 
rotors accumulate 1,000 cycles-since-new (CSN), the initial inspection 
must be done within 500 cycles-in-service. This is consistent with the 
requirements of Pratt & Whitney ASB PW4ENG A72-722, dated September 29, 
2000 and ASB PW4ENG A72-722, Revision 1, dated June 7, 2001. Proposed 
paragraph (a)(1) addresses front drum rotors that have fewer than 1,000 
cyles-since-new on the effective date of the AD in order to include 
them in the inspection program. Therefore, no changes are necessary and 
the proposed paragraph (a) is adopted without change.

Request for Same Effective Date

    One commenter requests that the effective date of the superseding 
AD be the same as the effective date of ASB PW4ENG A72-722, Revision 1, 
dated June 7, 2001. The commenter expresses concern that the effective 
date of the superseding AD would require changing the operators' 
ongoing inspection program.
    The FAA does not agree that the effective date of the superseding 
AD must be the same as the effective date of Revision 1 of the ASB. The 
actions in the AD are required unless already done. Also, the 
inspections are based on the number of cycles the HPC front drum rotor 
has accumulated since new. An on-going inspection program is not 
affected by a change in the effective date of the AD.

Incorporate Off-Wing Inspection Program

    One commenter notes that the proposal differs from the ASB, by not 
including the off-wing repetitive inspection program. The commenter 
states that when an engine is removed in accordance with another AD, AD 
2001-25-11, the engine may be returned to service without HPC 
disassembly. Therefore, the off-wing borescope inspection program is 
necessary in this

[[Page 42982]]

superseding AD and the commenter requests it be incorporated in the AD.
    The FAA partially agrees. The FAA does not agree that the off-wing 
borescope inspection program must be incorporated in the AD. In the 
discussion of comments section of AD 2001-20-13, published in the 
Federal Register on October 12, 2001, it was noted that there are 
differences between the manufacturer's service information and the AD. 
The FAA stated that ASB PW4ENG A72-722, Revision 1, dated June 7, 2001, 
provides procedures for operators to perform off-wing initial and 
repetitive HPC drum rotor inspections, and that the off-wing 
requirements are not mandated by AD 2001-20-13. The FAA evaluated a 20-
year cumulative risk assessment and determined that an acceptable level 
of safety will be met by requiring the on-wing inspections at the 
cyclic intervals detailed in the ASB. This description was not provided 
in the proposal. As the commenter states, operators performing the 
actions of AD 2001-20-13 have access to the HPC module, and can perform 
the off-wing HPC front drum rotor inspections of the ASB. It is noted 
in the ASB that the inspection program is intended for incorporation on 
engines installed on aircraft but may be incorporated on engines in the 
shop. The FAA agrees that using the off-wing procedures satisfies the 
repetitive inspection requirement. Therefore, paragraph (b) of the AD 
now reflects that option.

Concern Over Engines Already in ASB Compliance

    One commenter expresses concern that the proposal does not address 
engines that have met the requirements of the ASB before the effective 
date of the AD. Another commenter expresses concern that the proposal 
does not reference engines that have complied with the ASB during a 
shop visit before the effective date of the AD. The commenters request 
that paragraph (a) of the AD reference the off-wing borescope 
inspection in accordance with off-wing inspection paragraphs of ASB 
PW4ENG A72-722. The commenters also request that a paragraph be added 
to the AD to state that HPC drum rotors previously inspected in 
accordance with the on-wing and off-wing accomplishment instructions of 
the ASB's before the effective date of the AD, satisy the initial 
inspection requirements of the AD.
    The FAA partially agrees. The FAA does not agree that the off-wing 
borescope inspection program must be incorporated in the AD, as 
explained previously in the third comment response. The FAA agrees that 
inspection of HPC front drum rotors in accordance with the off-wing 
inspection instructions of the ASB before the effective date of the AD, 
satisfies the initial inspection requirements of the AD. Therefore, a 
new sub-paragraph (7) is added to paragraph (a) of the AD to allow the 
use of off-wing inspections of the HPC front drum rotors to satisfy the 
initial inspection requirement.

Inspect at Part Level

    One commenter states that the repetitive inspection program is not 
at part level and requests that the repetitive inspection program be at 
part level.
    The FAA disagrees that a part level inspection program should be 
added to the AD. Because the actions required by this AD are on-wing 
borescope inspections, the engine does not need to be disassembled to 
the part level in order to do the required actions.

Approve Proposal As Written

    Two commenters approve of the proposal as written. 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 Analysis

    The FAA estimates that this superseding AD will result in no 
additional costs to operators beyond those already incurred to comply 
with the current AD.

Regulatory Analysis

    This final 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 final 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 the 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 
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, 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 39-12461 (66 FR 
52023, October 12, 2001) and by adding a new airworthiness directive, 
Amendment 39-12787, to read as follows:

2002-12-15 Pratt & Whitney: Amendment 39-12787. Docket No. 2000-NE-
49-AD. Supersedes AD 2001-20-13, Amendment 39-12461.

    Applicability: This airworthiness directive (AD) applies to 
Pratt & Whitney (PW) models PW4052, PW4056, PW4060, PW4062, PW4152, 
PW4156A, PW4158, PW4460, and PW4462 turbofan engines. These engines 
are installed on but not limited to Boeing 747, 767, McDonnell 
Douglas MD-11, Airbus Industrie A300, and A310 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 (d) 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 failure of the high pressure compressor (HPC) front 
drum rotor from cracks, that could result in an uncontained engine 
failure and damage to the airplane, do the following:

[[Page 42983]]

Initial Inspection

    (a) Perform an initial borescope inspection for cracks in 
accordance with the Accomplishment Instructions, On-Wing paragraphs 
1 through 13, of Pratt & Whitney (PW) Alert Service Bulletin (ASB) 
No. PW4ENG A72-722, dated September 29, 2000 or Revision 1, dated 
June 7, 2001, as follows:
    (1) For HPC front drum rotors with fewer than 1,000 cycles-
since-new (CSN) on the effective date of this AD, perform an initial 
inspection within 500 cycles-in-service (CIS) after accumulating 
1,000 CSN.
    (2) For HPC front drum rotors with 1,000 CSN or more after the 
effective date of this AD, perform an initial inspection within 500 
CIS after the effective date of this AD.
    (3) If the presence of a crack needs to be confirmed, perform an 
eddy current inspection (ECI) within five flight cycles of the on-
wing borescope inspection.
    (4) If the presence of a crack needs to be confirmed and the 
suspect crack indication extends from the knife edges to the disk 
radius directly adjacent to the spacer wall of the sixth or seventh 
stage as shown in Figures 2 and 3 of PW ASB No. PW4ENG A72-722, 
dated September 29, 2000, or Revision 1, dated June 7, 2001, the ECI 
inspection must be done before further flight.
    (5) If the presence of a crack is confirmed, remove and replace 
the HPC front drum rotor with a serviceable part before further 
flight.
    (6) HPC front drum rotors fluorescent penetrant inspected at the 
last shop visit, as cited in the compliance section of the ASB, 
within 500 cycles of the effective date of this AD, satisfy the 
initial inspection requirement.
    (7) HPC front drum rotors inspected at the last shop visit, in 
accordance with Off-Wing paragraphs 1 through 13 of PW4ENG A72-722, 
dated September 29, 2000, or Revision 1, dated June 7, 2001, within 
500 cycles of the effective date of this AD, satisfy the initial 
inspection requirement.

Repetitive Inspections

    (b) Thereafter, perform borescope inspections within 2,200 
cycles-since-last-inspection, in accordance with the Accomplishment 
Instructions, On-Wing paragraphs 1 through 13, or Off-Wing 
paragraphs 1 through 13, of PW ASB No. PW4ENG A72-722, dated 
September 29, 2000, or Revision 1, dated June 7, 2001.
    (1) If the presence of a crack needs to be confirmed, perform an 
ECI within five flight cycles.
    (2) If the presence of a crack needs to be confirmed and the 
suspect crack indication extends from the knife edges to the disk 
radius directly adjacent to the spacer wall of the sixth or seventh 
stage as shown in Figures 2 and 3 of PW ASB No. PW4ENG A72-722, 
dated September 29, 2000, or Revision 1, dated June 7, 2001, the ECI 
inspection must be done before further flight.
    (3) If the presence of a crack is confirmed, remove and replace 
with a serviceable HPC front drum rotor before further flight.

Definition of Suspect Crack Indication

    (c) For the purposes of this AD, a suspect crack indication is 
defined as a response from the visual borescope inspection procedure 
that denotes the possible presence of a material discontinuity and 
requires interpretation to determine its significance.

Alternative Methods of Compliance

    (d) 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

    (e) 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 airplane to a location where the 
requirements of this AD can be done.

Documents That Have Been Incorporated by Reference

    (f) The inspections must be done in accordance with the 
following Pratt & Whitney Alert Service Bulletins (ASB's):

----------------------------------------------------------------------------------------------------------------
         Document No.                    Pages                 Revision                       Date
----------------------------------------------------------------------------------------------------------------
ASB PW4ENG A72-722............  All...................  Original..............  September 29, 2000.
    Total pages: 17.
ASB PW4ENG A72-722............  1-4...................  1.....................  June 7, 2001.
                                5.....................  Original..............  September 29, 2001.
                                6.....................  1.....................  June 7, 2001.
                                7-9...................  Original..............  September 29, 2001.
                                10-11.................  1.....................  June 7, 2001.
                                12-16.................  Original..............  September 29, 2001.
                                17....................  1.....................  June 7, 2001.
    Total pages: 17.
----------------------------------------------------------------------------------------------------------------

    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 
Street, East Hartford, CT 06108. Copies may be inspected, by 
appointment, 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

    (g) This amendment becomes effective on July 31, 2002.

    Issued in Burlington, Massachusetts, on June 14, 2002.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 02-15641 Filed 6-25-02; 8:45 am]
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