AD 97-11-06

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Pratt & Whitney PW4164 and PW4168 series turbofan engines. This action requires initial and repetitive visual inspections of the fan blades for surface damage and cracks, initial and repetitive lubrication of the fan blade part span shrouds, a one time ultrasonic inspection (UI) of the fan blade root attachment area for cracks, and a one time fan blade root attachment front corner radii inspection for proper dimension. Also, this AD requires visual inspection of the fan blades and removal of fan blades damaged by a bird strike as well as removal of blades immediately adjacent to damaged blades. In addition, this AD requires installation of an improved fan blade assembly as terminating action to the inspection requirements of this AD. This amendment is prompted by a report of a high N1 rotor imbalance and liberation of the fan containment system causing loss of structural support of theengine inlet cowl, following loss of a fan blade during a test. The actions specified in this AD are intended to prevent fan blade failure and separation at the root section, which could result in high N1 rotor imbalance, and liberation of the fan containment system, which can hazard the aircraft.

Final rule; request for comments.

97-11-06 Pratt & Whitney: Amendment 39-10035. Docket 97-ANE-10.
Applicability: Pratt & Whitney (PW) PW4164 and PW4168 series turbofan engines, installed on but not limited to Airbus Industrie A330 series aircraft.
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 fan blade failure and separation at the root section, which could result in high N1 rotor imbalance, and liberation of the fan containment system, which can hazard the aircraft, accomplish the following:
(a) Perform visual inspections of fan blades, Part Number (P/N) 55A221, for surface damage and cracks, and lubricate the fan blade shrouds, in accordance with the Accomplishment Instructions of PW SB No. PW4G-100-72-69, dated August 6, 1996, as follows:
(1) At the next "A" check inspection, not to exceed 500 hours time in service (TIS) after the effective date of this AD, whichever occurs first, perform the initial inspection of the fan blades and lubricate the fan blade shrouds.
(2) Thereafter, at each "A" check inspection, but not to exceed 500 hours TIS since last inspection and lubrication, whichever occurs first, inspect the fan blades and lubricate the fan blade shrouds.
(3) Prior to further flight, remove from service fan blades that do not meet the return to service criteria stated in the SB, and replace with serviceable parts.
(b) Perform an ultrasonic inspection (UI) of the fan blade root attachment area of fan blades, P/N 55A221, for cracks and perform a radius dimension inspection in accordance with Attachments 1 and 2 of PW SB No. PW4G-100-72-81, dated December 18, 1996, as follows:
(1) Prior to accumulating 2,500 total part cycles (TPC), or within 250 part cycles after the effective date of this AD, whichever occurs later.
(2) Prior to further flight, remove from service fan blades that do not meet the return to service criteria stated in the SB, and replace with serviceable parts.
(c) Following a bird strike, prior to further flight remove from service undamaged fan blades immediately adjacent on both sides to any fan blades exhibiting bird ingestion damage in addition to the damaged fan blades, in accordance with Airbus A330 Aircraft Maintenance Manual, Section 72-00-00, Subtask 72-00-00-210-093, Paragraph (A)(1), dated October 1, 1996, and replace with serviceable parts.
(d) Install a new or a modified fan blade assembly, in accordance with the requirements of PW SB No. PW4G-100-72-92, dated April 24, 1997, prior to December 31, 1998. Installation of a new or modified fan blade assembly, in accordance with PW SB No. PW4G-100-72-92, dated April 24, 1997, constitutes terminating action to the inspection requirements of paragraphs (a), (b), and (c) of this AD.
(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. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Engine Certification Office.
Note 2: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Engine Certification Office.
(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 aircraft to a location where the requirements of this AD can be accomplished.
(g) The actions required by this AD shall be done in accordance with the following PW SBs:

Document No.
Pages
Date
PW4G-100-72-69
1-10
August 6, 1996
Total pages: 10.

PW4G-100-72-81
1-8
December 18, 1996
NDIP-883
1-27
December 11, 1996
NDIP-893
1-9
December 11, 1996
Total pages: 44.

PW4G-100-72-92
1-24
April 24, 1997
Total pages: 24.

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) 565-6600, fax (860) 565-4503. 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.
(h) This amendment becomes effective on June 11, 1997.

The Federal Aviation Administration (FAA) received a report of a high level of N1 rotor imbalance on a Pratt & Whitney (PW) PW4164/PW4168 series turbofan engine during a fan blade out test. The high N1 rotor imbalance resulted from the loss of several fan blades after fan blade, Part Number (P/N) 55A221, was intentionally released for test purposes. This high imbalance of the N1 rotor also caused liberation of the fan blade containment system and loss of structural support to the engine inlet cowl. In revenue service, failure of the fan blade near the root attachment could be caused by metal fatigue. This condition, if not corrected, could result in fan blade failure and separation at the root section, which could result in high N1 rotor imbalance, and liberation of the fan containment system, which can hazard the aircraft.
The FAA has reviewed and approved the technical contents of PW Service Bulletin (SB) No. PW4G-100-72-69, dated August 6, 1996, that describes procedures for visual inspections of fan blades for cracks and surface damage, and lubrication of fan blade shrouds; PW SB No. PW4G-100- 72-81, dated December 18, 1996, that describes procedures for ultrasonic inspection (UI) of the fan blade root attachment area for cracks and fan blade root attachment front corner radii for proper dimension; and PW SB No. PW4G-100-72-92, dated April 24, 1997, that provides a new or a modified fan blade assembly design.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of the same type design, this AD is being issued to prevent fan blade failure and separation at the root section. This AD requires initial and repetitive visual inspections of the fan blades for surface damage and cracks, initial and repetitive lubrication of the fan blade shrouds, a one-time UI of the fan blade root attachment area for cracks, and a one-time fan blade root attachment front corner radii inspection for proper dimension. Fan blades that do not meet the return to service criteria specified in the applicable SBs must be replaced with serviceable parts. Also, this AD would require visual inspection of the fan blades and removal of damaged blades as well as removal of blades immediately adjacent to damaged blades following a bird strike. Additionally, this AD would require incorporation of a new or modified fan blade assembly prior to December 31, 1998. The actions are required to be accomplished in accordance with the SBs 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 97-ANE-10." 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 anunsafe 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. 106(g), 40113, 44701. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: