[Federal Register Volume 64, Number 137 (Monday, July 19, 1999)]
[Rules and Regulations]
[Pages 38557-38560]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-18099]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-42-AD; Amendment 39-11225; AD 99-15-06]
RIN 2120-AA64


Airworthiness Directives; AlliedSignal Inc. (Formerly Textron 
Lycoming) Model ALF502R-5 and ALF502R-3A Turborfan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to AlliedSignal Inc. Model ALF502R-5 and ALF502R-3A turbofan 
engines, that requires incorporation of an improved fan core inlet 
anti-ice system. This amendment is prompted by reports of uncommanded 
reduction of engine thrust (rollback) and loss of thrust control in 
icing conditions. The actions specified by this AD are intended to 
prevent ice accretion on the fan core inlet stator vane surfaces, which 
can result in engine rollback and loss of thrust control in icing 
conditions.

DATES: Effective September 17, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 17, 1999.

ADDRESSES: The service information referenced in this AD may be 
obtained from AlliedSignal Engines, P.O. Box 5218, Phoenix, AZ 85072-
2181; telephone (602) 365-2493, fax (602) 365-5577. This information 
may be examined at the Federal Aviation Administration (FAA), New 
England Region, Office of 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.

FOR FURTHER INFORMATION CONTACT: Eugene Triozzi, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7148, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to AlliedSignal Inc. Model ALF502R-5 
and ALF502R-3A turbofan engines was published in the Federal Register 
on December 14, 1998

[[Page 38558]]

(63 FR 68708). That action proposed to require installation of an 
improved fan core inlet anti-ice system, at the next shop visit, but no 
later than December 31, 2002.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Two commenters state that they should be allowed to use the 
altitude and operating restrictions, currently mandated by AD 96-14-09, 
rather than to require incorporation of the proposed engine anti-icing 
system modifications. One of the commenters proposes adoption of the 
altitude and operating restrictions regardless of icing conditions 
being present; while the other commenter proposes permanent use of AD 
96-14-09 restrictions in icing conditions only. The commenters state 
that no rollback events have occurred below 26,000 feet, and that the 
unsafe icing conditions are not prevalent at altitudes below 26,000 
feet. The commenters also state that the modifications are economically 
burdensome due to increased engine operating costs, and airplane air 
traffic control restrictions in congested areas. The FAA does not 
concur. The FAA acknowledges that no known rollback events have 
occurred below 26,000 feet altitude. However, the FAA considers the 
total operating hours accrued below that altitude, and the hours 
accrued in icing conditions below that altitude, to be insufficient to 
conclude that the interim restrictions, successfully imposed by AD 96-
14-09, would provide an acceptable level of safety for long-term 
unrestricted operation of an unmodified engine below that altitude. In 
addition, the technical data available to the FAA, including that 
provided by the commenters, does not show that significant mixed phase 
icing conditions are isolated to altitudes above 26,000 feet, or that 
the unmodified ALF502R-5 and ALF502R-3A engines are capable of long-
term unrestricted operation in the icing conditions present below that 
altitude.
    Moreover, the FAA is aware of two instances of ALF502R-5 engine 
rollback which occurred during inadvertent encounters of icing 
conditions at altitudes above 26,000 feet, after altitude and operating 
restrictions we originally established by AD 94-07-09, and superseded 
by AD 06-14-09. Accordingly, the FAA considers the current altitude 
restriction and operating procedures in icing conditions to be 
acceptable only for a finite period as necessary for implementation of 
engine modifications, rather than relying on interim changes to 
operating procedures.
    Therefore, based on the relatively limited fleet experience below 
the altitude limitation of 26,000 feet, the absence of sufficient 
engine and meteorological data to confidently isolate the ALF502R-5 
engine rollback phenomenon to altitudes above 26,000 feet, and the 
demonstrated possibility of inadvertent operation in icing conditions 
above 26,000 feet, the FAA does not concur that an acceptable long-term 
level of safety would be provided by limiting the operating envelope of 
unmodified engines to altitudes below 26,000 feet.
    One commenter proposes that the AD allow temporary installation of 
a single unmodified engine without requiring re-imposition of airplane 
operating restrictions. The change was proposed in order to reduce the 
frequency of aircraft being reidentified from restricted operation to 
unrestricted operation and back, to minimize airplane flight manual 
changes, and to reduce the likelihood of mis-placarding or pilot error. 
The commenter further states that the change is justifiable by 
statistical analysis of rollback likelihood. The FAA does not concur. 
The proposed AD is intended to require specific actions for 
incorporating ALF502R-5 engine modifications, rather than to address 
broader requirements with regard to airplane operation. Therefore, this 
submitted comment and response would not directly impact the 
requirements of the proposed rule.
    The actions proposed by the submitted comment would intentionally 
allow operation of an engine beyond its known operating capability, 
including unrestricted operation in icing conditions associated with 
engine rollback and power loss. The FAA recognizes that reinstallation 
of a single unmodified engine may require more instances of airplane 
flight manual changes and cockpit placard than would be required 
otherwise. However, the FAA does not consider the need for these 
additional tasks to warrant allowing operation of an unmodified engine 
beyond its known operating capability. Moreover, installation of 
cockpit placards and airplane flight manual revisions are currently 
required by AD 96-14-09, and these tasks are considered appropriate for 
notifying crews of applicable altitude restrictions and operating 
procedures for unmodified engines. Accordingly, the FAA does not 
consider that the potential for mis-placarding or crew error to 
necessitate consideration of other measures.
    In summary, because of the likelihood of rollback and power loss if 
ALF502R-5 engines are allowed to operate unrestricted in icing 
conditions, the FAA considers it necessary to continue to impose the 
operating restrictions in AD 96-14-09 if a single unmodified engine is 
installed and operated in icing conditions. The FAA continues to 
consider the installation of cockpit placards and flight manual 
revisions as acceptable means to identify when an unmodified engine is 
installed and requires AD 96-14-09 restrictions.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    There are approximately 982 engines of the affected design in the 
worldwide fleet. The FAA estimates that 100 engines installed on 
aircraft of U.S. registry will be affected by this AD, that it will 
take approximately 30 work hours per engine to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $75,000 per engine. Based on these 
figures, the cost impact of the AD's required incorporation of engine 
modifications for U.S. operators is estimated to be $7,680,000.
    In addition to the above engine modifications, further aircraft 
modifications specified by BAe SB No. 71-68-01581A, and BAe SB No. 26-
40-01601A, Revision 1, are required prior to installation of modified 
engines onto BAe 146 aircraft. The FAA estimates that 20 aircraft of 
U.S. registry will be affected by this proposed AD, that it will take 
approximately 33 work hours per aircraft to accomplish the required 
actions, and that the average labor rate is $60 per work hour. Required 
parts will cost approximately $2,400 per aircraft. Based on these 
figures, the cost impact for incorporation of aircraft modifications 
required by the AD on U.S. operators is estimated to be $87,600.
    Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $7,767,600.
    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 Federalism Assessment.

[[Page 38559]]

    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

99-15-06  AlliedSignal Inc.: Amendment 39-11225. Docket 98-ANE-42-
AD.

    Applicability: AlliedSignal Inc. (formerly Textron Lycoming) 
ALF502R-5 and ALF502R-3A model turbofan engines, installed on but 
not limited to British Aerospace (BAe) 146-100A, -200A and -300A 
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/operated 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 conditions 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 uncommanded reduction of engine thrust and loss of 
thrust control in icing conditions, accomplish the following:
    (a) At the next engine shop visit after the effective date of 
this AD, but not later than December 31, 2002, install an improved 
fan core inlet anti-ice system in accordance with Accomplishment 
Instructions, Paragraphs 2.B. through 2.I.(1-4), of AlliedSignal 
Inc. Service Bulletin (SB) No. ALF/LF 72-1020, Revision 2, dated 
September 30, 1998. In order to install engines with the required 
modifications onto BAe 146-100A, -200A and -300A series aircraft, 
accomplish BAe Regional Aircraft SB No. 26-40-01601A, dated March 
25, 1998, and BAe Regional Aircraft SB No. 71-68-01581A, Revision 1, 
dated March 25, 1998.
    (b) For the purpose of this AD, an engine shop visit is defined 
as maintenance that includes separation of either the fan module or 
the combustor turbine module from the remainder of the engine.
    (c) 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.

    (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 airplane 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 following SBs:

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         Document No.                    Pages                    Revision                       Date
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AlliedSignal Inc. No. ALF/LF    1.....................  2..........................  September 30, 1998.
 72-1020.
                                2.....................  1..........................  June 3, 1998.
                                3-14..................  Original...................  March 11, 1998.
                                15....................  1..........................  June 3, 1998.
                                16....................  Original...................  March 11, 1998.
                                17....................  1..........................  June 3, 1998.
                                18-20.................  2..........................  September 30, 1998.
                                21, 22................  Original...................  March 11, 1998.
                                23, 24................  1..........................  June 3, 1998.
                                25....................  Original...................  March 11, 1998.
                                26-29.................  2..........................  September 30, 1998.
                                30-33.................  Original...................  March 11, 1998.
                                34, 35................  2..........................  September 30, 1998.
                                36....................  1..........................  June 3, 1998.
                                37....................  2..........................  September 30, 1998.
                                38....................  1..........................  June 3, 1998.
    Total Pages: 38.
BAe Regional Aircraft No. 26-   1-7...................  Original...................  March 25, 1998.
 40-01601A.
    Total Pages: 7.
BAe Regional Aircraft No. 71-   1-3...................  1..........................  March 25, 1998.
 68-01581A.
                                4-18..................  Original...................  August 14, 1997.
    Total Pages: 18.
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    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 Engines, P.O. Box 
5218, Phoenix, AZ 85072-2181, telephone (602) 365-2493, fax (602) 
365-5577. Copies may be inspected at the FAA, New England Region, 
Office of 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.
    (f) This amendment becomes effective on September 17, 1999.


[[Page 38560]]


    Issued in Burlington, Massachusetts, on July 9, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-18099 Filed 7-16-99; 8:45 am]
BILLING CODE 4910-13-M