[Federal Register Volume 63, Number 198 (Wednesday, October 14, 1998)]
[Proposed Rules]
[Pages 55056-55059]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-27462]


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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).

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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

[[Page 55057]]

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-
[email protected]''. 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 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.

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

[[Page 55058]]

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

[[Page 55059]]

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. 98-27462 Filed 10-13-98; 8:45 am]
BILLING CODE 4910-13-U