AD 98-17-10

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 98-17-10 that was sent previously to all known U.S. owners and operators of Pratt & Whitney Canada (PWC) PW530A series turbofan engines by individual letters. This AD requires recording engine surge events in the aircraft maintenance records. If an engine surge event is experienced, this AD requires, prior to the next flight, inspecting that engine for evidence of second stage stator vanes rubbing on the compressor rotor. In addition, this AD requires reworking all affected engines to increase the clearance between the second stage stator vanes and the compressor rotor. This amendment is prompted by reports of 4 inflight engine shutdowns and 2 additional unscheduled engine removals for significant compressor rotor damage. The actions specified by this AD are intended to prevent an inflight engine shutdown due to rubbing of the second stage stator vanes on the compressor rotor.

Final rule, request for comments.

98-17-10 Pratt & Whitney Canada: Amendment 39-10817. Docket 98-ANE-58-AD.
Applicability: Pratt & Whitney Canada (PWC) PW530A series turbofan engines, with serial numbers (S/Ns) PCE-DA0001 through PCE-DA0059, and S/Ns PCE-DA0061 through PCE-DA0064 (S/N PCE-DA0060 is not affected, as it was shipped with the increased type design clearance). These engines are installed on but not limited to Cessna Citation Model 550 Bravo 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 inflight engine shutdown due to rubbing of the second stage stator vanes on the compressor rotor, accomplish the following:
(a) In the event of an engine surge, make a record of the engine which surged and the date and approximate time of the event in the aircraft maintenance records. For this purpose, an engine surge is defined as unstable engine operation which is accompanied by unusual sounds which could be described as bangs, pops, growls, or rumbles and which may also be accompanied by increased engine vibration levels.
(b) If an engine surge event is experienced, prior to the next flight, inspect that engine for evidence of rubbing of the second stage stator vanes on the compressor rotor inaccordance with PWC Service Bulletin (SB) No. PW500-72-30063, Revision 2, dated July 10, 1998.
(c) If evidence of rubbing is discovered, prior to further flight, remove from service the engine that experienced rubbing and replace with a serviceable engine.
(d) Within 200 hours time in service (TIS) after the effective date of this AD, or prior to December 31, 1998, whichever occurs first, rework all affected engines identified by S/N in the applicability of this AD to increase the clearance between the second stage stator vanes and the compressor rotor, in accordance with PWC SB No. PW500-72-30044, Revision 2, dated July 10, 1998. Completion of this rework constitutes terminating action to the inspection requirements 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 appropriateFAA 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) The requirements of this AD shall be done in accordance with the following PWC SBs:

Document No.
Pages
Revision
Date
PW500-72-30063
1-5
2
July 10, 1998
Total pages: 5.

PW500-72-30044
1-6
2
July 10, 1998
Total pages: 6.

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 Canada, Inc., 1000 Marie-Victorin, Longueuil, Quebec, Canada J4G 1A1; Attn.: Supervisor, Publications Customer Service (01CA4); telephone (514) 647-2705, fax (514) 647-2702. Copies may be inspected at the FAA, New England Region, Officeof 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.
(g) This amendment becomes effective October 21, 1998, to all persons except those persons to whom it was made immediately effective by priority letter AD 98-17-10, issued August 7, 1998, which contained the requirements of this amendment.

Transport Canada, which is the airworthiness authority for Canada, recently notified the Federal Aviation Administration (FAA) that an unsafe condition may exist on certain Pratt & Whitney Canada (PWC) PW530A series turbofan engines. Transport Canada advises that they have received reports of 4 inflight engine shutdowns and 2 additional unscheduled engine removals for significant compressor rotor damage. The investigation revealed that compressor rotor damage and a high rate of inflight engine shutdowns result from rubbing of the second stage stator vanes on the compressor rotor. The original type design second stage stator clearance was insufficient to prevent rubbing of the stator vanes on the compressor rotor during all phases of engine operation. This condition, if not corrected, can result in an inflight engine shutdown due to rubbing of the second stage stator vanes on the compressor rotor.
PWC has issued Service Bulletin (SB) No. PW500-72-30063, Revision 2, dated July 10, 1998, that specifies inspection procedures for rubbing of the second stage stator vanes on the compressor rotor, and SB No. PW500-72-30044, Revision 2, dated July 10, 1998, that specifies procedures for reworking the engine to increase the clearance between the second stage stator vanes and the compressor rotor. Transport Canada classified these SBs as mandatory and issued airworthiness directive (AD) CF-98-18, dated July 16, 1998, in order to assure the airworthiness of these engines in Canada.
This engine model is manufactured in Canada and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, Transport Canada has kept the FAA informed of the situation described above. The FAA has examined the findings of Transport Canada, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
On August 7, 1998, the Federal Aviation Administration (FAA) issued priority letter airworthiness directive (AD) 98-17-10, applicable to PWC PW530A series turbofan engines.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of this same type design, this AD requires, for aircraft with one or more affected engines identified by serial numbers (S/Ns) in the applicability section of this AD, recording engine surge events in the aircraft maintenance records. If an engine surge event is experienced, this AD requires, prior to the next flight, inspecting that engine for evidence of second stage stator vanes rubbing on the compressor rotor. If evidence of rubbing is discovered, this AD requires, prior to further flight, removal from service of the engine that experienced rubbing and replacement with a serviceable engine. In addition, this AD requires, within 200 hours time in service (TIS) after the effective date of this AD, or prior to December 31, 1998, whichever occurs first, reworking all affected engines to increase the clearance between the second stage stator vanes and the compressor rotor. The calendar end-date was determined based upon risk analysis. The actions are required to be accomplished in accordance with the SBs described previously.
Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on August 7, 1998, to all known U.S. owners and operators of PWC PW530A series turbofan engines. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to Section 39.13 of part 39 of the Federal Aviation Regulations (14 CFRpart 39) to make it effective to all persons. 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 98-ANE-58-AD." 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. 106(g), 40113, 44701. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: