[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
