Airworthiness directives: AlliedSignal Inc.,

[Federal Register: October 14, 1998 (Volume 63, Number 198)]

[Proposed Rules]

[Page 55056-55059]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr14oc98-20]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-ANE-36]

RIN 2120-AA64

Airworthiness Directives; AlliedSignal Inc. ALF502 and LF507 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the supersedure of two existing airworthiness directives (ADs), applicable to AlliedSignal Inc. ALF502 and LF507 series turbofan engines, that currently require rework or replacement of No. 4 and 5 bearing oil system hardware, initial and repetitive inspections of the oil system, optional installation of an improved oil filter bypass valve, and repetitive inspection of No. 4 and 5 bearing oil inlet tube, to ensure the integrity of the reduction gear system and overspeed protection system. This action would require replacement of the existing power turbine bearing housing assembly with a new, improved power turbine bearing housing assembly, and installation of a reworked or modified fourth turbine rotor disk assembly as a part of a design change to the new No. 4 bearing configuration that eliminates the requirement for repetitive inspections of oil system and No. 4 and 5 bearing oil inlet tube assembly. This proposal is prompted by one report of a contained power turbine rotor shaft separation forward of the Stage 4 low pressure turbine (LPT) rotor on an AlliedSignal

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Inc. ALF502R-5 engine. The LPT failure was caused by improper inspection of the engine oil system required by AD 97-05-11 R1. The actions specified by the proposed AD are intended to prevent No. 4 and 5 duplex bearing failure, which can result in a Stage 4 LPT rotor failure, an uncontained engine failure, and damage to the aircraft.

DATES: Comments must be received by December 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 96-ANE-36, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: ``9-ad- engineprop@faa.dot.gov''. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule 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. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Raymond Vakili, Aerospace Engineer, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone (562) 627-5262; fax (562) 627-5210.

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 notice 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 filedin 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.

Availability of NPRMs

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. 96-ANE-36, 12 New England Executive Park, Burlington, MA 01803-5299.

Discussion

On December 9, 1980, the Federal Aviation Administration (FAA) issued airworthiness directive (AD) 80-22-53, amendment 39-3995 (45 FR 83202, December 18, 1980), applicable to AlliedSignal Inc. (formerly Avco Lycoming) ALF502L and L2 series turbofan engines, to require installation of improved fourth turbine nozzle and fire shield, and replacement and repetitive inspection of the No. 4 and 5 bearing oil inlet tubes.

On July 17, 1987, the FAA also issued 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. That action was prompted by reports of power turbine overspeed and uncontained blade failure resulting from reduction gear system decouple and inaccurate power turbine 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 received reports of four additional failures of the stage 4 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 seizures 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 July 23, 1997, the FAA issued AD 97-05-11 R1, Amendment 39-10091 (62 FR 41262, August 1, 1997), to supersede AD 87-06-52 R1 to require more stringent oil system 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 R1, the FAA has received one report of a contained power turbine rotor shaft separation forward of Stage 4 LPT rotor on an AlliedSignal Inc. ALF-502-R5 engine. The LPT failure was caused by improper inspection of the engine oil system required by AD 97-05-11 R1.

The FAA has reviewed and approved the technical contents of the accomplishment instructions paragraphs of AlliedSignal Inc. Service Bulletin (SB) No. ALF/LF 72-1030, Revision 1, dated February 23, 1998, and AlliedSignal Inc. SB No. ALF/LF 72-1040, dated October 20, 1997, that describe procedures for installation of a reworked or modified fourth turbine rotor disk assembly, and that describes procedures for replacement of the existing power turbine bearing housing assembly with a new, improved power turbine bearing housing assembly.

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede ADs 80-22-53 and 97-05-11 R1 to require replacement of the existing power turbine bearing housing assembly with a new, improved power turbine bearing housing assembly, and installation of a reworked or modified fourth turbine rotor disk assembly as a part of design change to the new No. 4 bearing configuration, that will eliminate the requirements for repetitive inspections of oil system and No. 4 and 5 bearing oil inlet tube assembly.

There are approximately 1,500 engines of the affected design in the worldwide fleet. The FAA estimates that 300 engines installed on aircraft of U.S. registry would be affected by this proposed AD, that it would take approximately 20 work hours per engine to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Required parts would cost approximately $30,000 per engine. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $9,540,000.

The regulations proposed herein would not have substantial direct effects on the States, on the relationship

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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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 39-3995 (45 FR 83202, December 18, 1980), and amendment 39-10091 (62 FR 41262, August 1, 1997) and by adding a new airworthiness directive to read as follows:

   AlliedSignal Inc.: Docket No. 96-ANE-36. Supersedes AD 80-22-53, Amendment 39-3995, and AD 97-05-11 R1, Amendment 39-10091.

   Applicability: AlliedSignal Inc. (formerly Textron Lycoming, Avco Lycoming) Model ALF502 and LF507 series turbofan engines, installed on but not limited to British Aerospace BAe 146-100A, BAe 146-200A, BAe 146-300A, 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 (h) 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 a Stage 4 low pressure turbine (LPT) rotor failure, an uncontained engine failure, and damage to the aircraft, accomplish the following:

   (a) For AlliedSignal Inc. (formerly Textron Lycoming and Avco Lycoming) ALF502L and ALF502L2 series engines, prior to further flight, rework or replace the following parts and reassemble in accordance with Avco Lycoming Service Bulletin (SB) No. ALF502-72- 0008, Revision 1, dated October 14, 1980, and SB No. ALF502-72-0010, dated October 14, 1980:

   (1) Remove No. 4 and 5 bearing inlet tube assembly, part number (P/N) 2-141-380-07/-08/-11/-12 and replace with P/N 2-141-380-13/- 14.

   (2) Remove adapter assembly, P/N 2-141-640-01 and replace with P/N 2-141-640-02.

   (3) If not previously incorporated, install: Bracket, P/N 2-143- 049-01, spacer P/N 2-143-051-01, two bolts P/N STD3061-11, Clamp P/N TA1501H05, Bolt P/N MS9565-06, Nut P/N STD3073-3, and Washer P/N STD3035C2.

   (4) Rework fourth stage turbine nozzle, P/N 2-141-150-38, to P/N 2-141-150-42, or P/N 2-141-150-39 to P/N 2-141-150-41 in accordance with SB No. ALF502-72-0010.

   (5) Rework upper half of fire shield, P/N 2-163-990-04 to 2-163- 990-07, or P/N 2-163-990-05 to 2-163-990-08 in accordance with SB No. ALF502-72-0010.

   (6) Install: Washer, P/N 2-163-585-01, and Spring P/N 2-163-586- 01, and Retainer P/N 2-163-584-01.

   (7) Remove oil feed line, P/N 2-173-240-02 and replace with P/N 2-303-377-01.

   (8) Remove jam nut, P/N R44118P05W. (The function of the jam nut is accomplished by the parts in paragraphs (a)(6) and (a)(7) of this AD.)

   (9) Remove oil inlet support bracket, P/N 2-141-335-02 and replace with P/N 2-141-335-03.

   (b) After replacement of the No. 4 and 5 bearing oil inlet tube and associated hardware in accordance with paragraph (a) of this AD, inspect the No. 4 and 5 bearing oil inlet tube at intervals not to exceed 100 hours time in service (TIS) since last inspection for chafing, in accordance with Avco Lycoming SB No. ALF502-72-0008, Revision 1, dated October 14, 1980. Prior to further flight, replace oil inlet tubes which exhibit chafing in excess of 0.010 inch deep with serviceable parts.

   (c) For ALF502R series engines equipped with oil filter bypass valve, P/N 2-303-432-01, accomplish the following:

   (1) Inspect the engine oil filter bypass valve for leakage within the next 25 hours TIS or 25 flights in service, whichever occurs first, from the effective date of this AD, in accordance with Avco Lycoming Textron 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 hours TIS 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 No. 4 and 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 hours TIS 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 (c)(1) and (c)(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.

   (d) 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

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   described in the Accomplishment Instructions paragraphs of the applicable AlliedSignal Inc. SBs referenced in paragraphs (d)(1), (d)(2), (d)(3), and (d)(4) of this AD, within the next 25 hours TIS 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.

   (e) Modify the fourth turbine rotor disk assembly at the next access to the No. 4 and 5 duplex bearing assembly during the engine shop visit not to exceed 6,000 cycles in service (CIS) or 6,000 hours TIS, whichever occurs first, from the effective date of this AD, in accordance with the accomplishment instructions paragraph of AlliedSignal Inc. SB No. ALF/LF 72-1030, Revision 1, dated February 23, 1998.

   (f) Modify the power turbine bearing housing assembly at the next access to the No. 4 and 5 duplex bearing assembly during the engine shop visit not to exceed 6,000 CIS or 6,000 hours TIS, whichever occurs first, from the effective date of this AD, in accordance with the accomplishment instructions paragraph of AlliedSignal Inc. SB No. ALF/LF 72-1040, dated October 20, 1997.

   (g) Performance of the modifications described in paragraphs (e) and (f) of this AD constitutes terminating action to the repetitive inspection requirements of paragraphs (b), (c), and (d) of this AD.

   Note 3: Installation of a reworked or modified fourth turbine rotor disk assembly as a part of a design change to the new No. 4 bearing configuration that eliminates the requirements for repetitive inspections of oil system does not relieve the operators from accomplishment of the engine oil system inspection in accordance with the engine manufacturer's applicable maintenance documents.

   (h) 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, 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 4: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Los Angeles Aircraft Certification Office.

   (i) 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.

   Issued in Burlington, Massachusetts, on October 6, 1998. Ronald L. Vavruska, Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.

   [FR Doc. 98-27462Filed10-13-98; 8:45 am]

   BILLING CODE 4910-13-U