AD 97-05-11 R1

This amendment revises an existing airworthiness directive (AD), applicable to AlliedSignal Inc. ALF502 and LF507 series turbofan engines, that currently requires initial and repetitive inspections of the oil system chip detectors and oil filter bypass valve, and optional installation of an improved oil filter bypass valve, to ensure the integrity of the reduction gear system and overspeed protection system. This amendment adds an initial inspection threshold for the oil maintenance requirements that was inadvertently omitted from AD 97-05-11, and makes editorial corrections. Paragraphs (b) through (f) of AD 97-05-11 have been rearranged in this AD to make these corrections. This amendment is prompted by the inadvertent omission of the initial inspection threshold. The actions specified by this AD are intended to prevent No. 4 and 5 duplex bearing failure, which can result in a Stage 4 low pressure turbine (LPT) rotor failure, an uncontained engine failure, and damage tothe aircraft.

Final rule; request for comments.

97-05-11 R1 AlliedSignal Inc.: Amendment 39-10091. Docket 96-ANE-36. Revises AD 97-05-11, Amendment 39-9955.
Applicability: AlliedSignal Inc. and Textron Lycoming Model ALF502 and LF507 series turbofan engines, installed on but not limited to British Aerospace BAe146-100A, BAe146-200A, BAe146-300A, AVRO 146-RJ70A, AVRO 146-RJ85A, AVRO 146-RJ100A, and Canadair Model CL-600-1A11 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 (c) 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 No. 4 and 5 duplex bearing failure, which can result in a Stage 4 low pressure turbine (LPT) rotor failure, an uncontained engine failure, and damage to the aircraft, accomplish the following:
(a) For ALF502R series engines equipped with oil filter bypass valve, part number (P/N) 2-303-432-01, accomplish the following:
(1) Inspect the engine oil filter bypass valve for leakage within the next 25 engine hours or 25 flights in service, whichever occurs first, from the effective date of this AD, in accordance with Avco Lycoming Textron Service Bulletin (SB) No. ALF 502R-79-0162, Original, dated March 23, 1987, or Revision 1, dated May 26, 1987. Prior to further flight, remove from service oil filters exhibiting any leakage and replace with serviceable parts.
(2) Thereafter, inspect the oil filter bypass valve for any leakage in accordance with Avco Lycoming Textron SB No. ALF 502R-79-0162, Original, dated March 23, 1987, or Revision 1, dated May 26, 1987, at intervals not to exceed 50 engine hours or 50 flights in service since last inspection, whichever occurs first, and at the same time accomplish the following:
(i) Visually inspect the following engine chip detectors for metal contamination:
(A) For engines with a full flow chip detector installed, inspect the full flow chip detector.
(B) For engines without a full flow chip detector installed, inspect the chip detectors located in the accessory gearbox, Number 2 bearing scavenge line, and Number 4/5 bearing scavenge line.
(ii) For engines with engine chip detectors exhibiting Condition 3, or Condition 2, or Condition 1 where the oil filter bypass indicator is extended, prior to further flight, remove oil filter bypass valves exhibiting any leakage and replace with a serviceable part.
Note 2: Chip detector conditions are described in Avco Lycoming Textron SB No. ALF502R- 72-0160, Revision 1, dated March 23, 1987, Figures 1, 2 and 3.
(3) At the next engine shop visit, or within 2,500 engine hours after the effective date of this AD, whichever occurs first, conduct the oil filter bypass valve spring compression force check, in accordance with Avco Lycoming Textron SB No. ALF 502R-79-0162, Original, dated March 23, 1987. Oil filter bypass valves which do not comply with the spring compression force limits contained in Avco Lycoming Textron SB No. ALF 502R-79-0162, Original, dated March 23, 1987, must be removed and replaced with oil filter bypass valve, P/N 2-303-432-02. Replacement of oil filter bypass valve, P/N 2-303-432-01, with the improved oil filter bypass valve, P/N 2-303- 432-02, constitutes terminating action for the inspection requirements of paragraphs (a)(1) and (a)(2) of this AD.
(4) For the purpose of this AD, an engine shop visit is defined as engine maintenance that entails any of the following:
(i) Separation of a major engine flange (lettered or numbered) other than flanges mating with major sections of the nacelle reverser. Separation of flanges purely for purposes of shipment, without subsequent internal maintenance, is not a "shop visit."
(ii) Removal of a disk, hub, or spool.
(iii) Removal of the fuel nozzles.
(b) For ALF502R, ALF502L, LF507-1F, and LF507-1H series engines, equipped with the No. 4 and 5 duplex bearing assembly numbers 2-141-930-01, 2-141-930-02, or 2-141-930-03, perform the repetitive oil system maintenance and inspections in accordance with the intervals and procedures described in the Accomplishment Instructions paragraphs of the applicable AlliedSignal Inc. SBs referenced in paragraphs (b)(1), (b)(2), (b)(3), and (b)(4) of this AD, within the next 25 engine hours or 25 flights in service, whichever occurs first, from the effective date of this AD.
(1) For ALF502R series engines, in accordance with AlliedSignal Inc. SB No. ALF502R 79-9, Revision 1, dated November 27, 1996.
(2) For ALF502L series engines, in accordance with AlliedSignal Inc. SB No. ALF502L 79-0171, Revision 1, dated November 27, 1996.
(3) For LF507-1F series engines, in accordance with AlliedSignal Inc. SB No. LF507- 1F-79-5, Revision 1, dated November 27, 1996.
(4) For LF507-1H series engines, in accordance with AlliedSignal SB No. LF507-1H- 79-5, Revision 1, dated November 27, 1996.
(c) An alternative method of compliance or adjustment of the initial compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles Aircraft 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, Los Angeles Aircraft Certification Office.
Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.
(d) 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.
(e) The actions required by this AD shall be done in accordance with the accomplishment instructions paragraphs of the following documents:

Document No.
Pages
Revision
Date
Avco Lycoming Textron SB No. ALF 502R720160
1-7
2
May 26, 1987
Total Pages: 7

Avco Lycoming Textron SB No. ALF 502R-72-0160
1-7
1
March 23, 1987
Total Pages: 7

Avco Lycoming Textron SB No. ALF 502R-79-0162
1-5
2
September 8, 1987
Total Pages: 5

Avco Lycoming Textron SB No. ALF 502R-79-0162
1-4
1
May 26, 1987
Total Pages: 4

Avco Lycoming Textron SB No. ALF 502R-79-0162
1-6
Original
March 23, 1987
Total Pages: 6

AlliedSignal Inc. SB No. ALF502R 79-9
1
1
November 27, 1996

2
Original
June 29, 1995

3-7
1
November 27, 1996

8
Original
June 29, 1995

9-12
1
November 27, 1996

13,14
Original
June 29, 1995
Total Pages: 14

AlliedSignal Inc. SB No. LF507-1F 79-5
1
1
November 27, 1996

2
Original
June 29, 1995

3-7
1
November 27, 1996

8
Original
June 29, 1995

9-12
1
November 27, 1996

13-14
Original
June 29, 1995
Total Pages: 14

AlliedSignal Inc. SB No. LF507-1H 79-5
1
1
November 27, 1996

2
Original
June 29, 1995

3-7
1
November 27, 1996

8
Original
June 29, 1995

9-12
1
November 27, 1996

13-14
Original
November 3, 1995
Total Pages: 14

AlliedSignal Inc. SB ALF502L 79-0171
1
1
November 27, 1996

2
Original
November 3, 1996

3-7
1
November 27, 1996

8
Original
November 3, 1995

9-12
1
November 27, 1996

13-14
OriginalNovember 3, 1995
Total Pages: 14

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 AlliedSignal Aerospace, Attn: Data Distribution, M/S 64-3/2101-201, P.O. Box 29003, Phoenix, AZ 85038-9003; telephone (602) 365-2493, fax (602) 365-5577. 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.
(f) This amendment becomes effective on August 18, 1997.

On July 17, 1987, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 87-06-52 R1, Amendment 39-5688 (52 FR 31979, August 25, 1987), applicable to AlliedSignal Inc. (formerly Avco Lycoming Textron) ALF502R series turbofan engines, to require initial and repetitive inspections of the oil system chip detectors and oil filter bypass valve, and optional installation of an improved oil filter bypass valve, to ensure the integrity of the reduction gear system and overspeed protection system. The optional installation of the improved oil filter bypass valve provides terminating action for the repetitive oil filter bypass valve spring compression test also required by AD 87-06-52 R1. That action was prompted by reports of power turbine (PT) overspeed and uncontained PT blade failure resulting from reduction gear system decouple and inaccurate PT overspeed signal generation. That condition, if not corrected, could result in No. 4 and 5 duplex bearing failure, which can result in a Stage 4 low pressure turbine (LPT) rotor failure, an uncontained engine failure, and damage to the aircraft.
Since the issuance of AD 87-06-52 R1, the FAA has received reports of four additional failures of the Stage 4 low pressure turbine (LPT) rotor on AlliedSignal Inc. ALF502 series turbofan engines. The LPT failures were caused by failure of the No. 4 and 5 duplex bearing, causing bearing seizure and LPT shaft separation between the two bearings forward of the Stage 4 LPT rotor. In one incident the Stage 4 LPT shaft separation caused an uncontained rotor failure.
On March 27, 1997, the FAA issued AD 97-05-11, Amendment 39-9955 (62 FR 15378, April 1, 1997), to supersede AD 87-06-52 R1 to require more stringent oil system inspection requirements, including inspection of the full flow chip detector, oil filter impending bypass button, oil acid number, oil color, and oil quantity.
Since the issuance of AD 97-05-11, the FAA has determined that the initial inspection threshold for the oil maintenance requirements were inadvertently omitted. This amendment adds the initial inspection threshold for the oil maintenance requirements and corrects the service bulletin numbers referenced in the AD.
The FAA has reviewed and approved the technical contents of AlliedSignal Inc. Service Bulletins (SBs): No. ALF502L 79-0171, Revision 1, dated November 27, 1996; No. LF507-1F 79-5, Revision 1, dated November 27, 1996; No. LF507-1H 79-5, Revision 1, dated November 27, 1996; and No. ALF502R 79-9, Revision 1, dated November 27, 1996. These SBs describe procedures for oil system inspection. In addition, FAA has reviewed and approved the technical content of Textron Lycoming SB No. ALF 502R-79-0162, Revision 2, dated September 8, 1987, to ensure that portions of the accomplishment instructions paragraph of this SB continues to provide the terminating action for the oil filter bypass valve compression spring test. Also, the FAA has reviewed and approved the technical contents of Avco Lycoming Textron SB No. ALF 502R-72-0160, Revision 2, dated May 26, 1987, and Revision 1, dated March 23, 1987, that describe procedures for chip detector inspections. Finally, the FAA has reviewed and approved the technical contents of Avco Lycoming Textron SB No. ALF 502R-79-0162, Revision 1, dated May 26, 1987, and Original, dated March 23, 1987, that describe procedures of inspection of the oil filter bypass valve.
Since an unsafe condition has been identified that is likely to exist or develop on other engines of this same type design, this AD revises AD 97-05-11 to add the initial inspection threshold for the oil maintenance requirements which was inadvertently omitted from AD 97-05-11, Amendment 39-9955, paragraphs (b) through (e), and corrects the editorial errors in paragraph (a)(1) and (c). Paragraphs (b) through (f) are re-arranged as a result of these corrections. The actions are required to be accomplished inaccordance 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 96-ANE-36." The postcard will be date stamped and returned to the commenter.
The regulations adopted herein will not have substantial directeffects 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 removing Amendment 39-9955 (62 FR 15378, April 1, 1997) and by adding a new airworthiness directive, Amendment 39-10091, to read as follows: