[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Rules and Regulations]
[Pages 4899-4900]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1701]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-ANE-09; Amendment 39-9897; AD 97-02-12]
RIN 2120-AA64
Airworthiness Directives; Rolls-Royce plc RB211-535E4 and -535E4-
B Series Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to Rolls-Royce plc RB211-535E4 and -535E4-B series turbofan
engines, that requires installation of an improved fuel flow governor
that incorporates revised minimum compressor discharge P4 stop
settings. This amendment is prompted by reports of engine rundowns
during low idle descent during icing conditions. The actions specified
by this AD are intended to prevent compressor stall and subsequent
engine rundown on one or both engines.
DATES: Effective April 4, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of April 4, 1997.
ADDRESSES: The service information referenced in this AD may be
obtained from Rolls-Royce plc, P.O. Box 31, Moor Lane, Derby, DE248BJ,
United Kingdom; telephone 1332-249428, fax 1332-249423. This
information may be examined at the Federal Aviation Administration
(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.
FOR FURTHER INFORMATION CONTACT: Daniel Kerman, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7130, fax (617) 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 Rolls-Royce plc (R-R) RB211-535
series turbofan engines was published in the Federal Register on June
12, 1996 (61 FR 29697). That action proposed to require installation of
an improved Fuel Flow Governor (FFG) that incorporate revised minimum
compressor discharge P4 stop settings. This revised setting will raise
the steady state low idle schedule above the idle conditions
experienced during any of the prior engine rundown events. This
schedule increase will result in a substantial increase in Intermediate
Pressure Compressor (IPC) stall margin, a moderate increase in High
Pressure Compressor (HPC) stall margin, as well as provide the
additional benefit of increased ice accretion tolerance due to
increased compressor airflow and increased rotor speed. This action
must be accomplished within 9 calendar months after the effective date
of this AD. The FAA has determined the calendar end-date based on the
time interval required for fleet modification. The actions would be
required to be accomplished in accordance with R-R Mandatory (SB) No.
RB.211-73-B869, Revision 1, dated May 24, 1996.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter states that the proposed AD should be modified to
eliminate the shop visit requirement and to impose a calendar end-date
for compliance with the proposed FFG modification. The FAA concurs, and
has revised this final rule to delete the shop visit requirement. The
FAA has determined that the shop visit requirement is not necessary and
that a calendar end-date will assure an adequate level of safety.
One commenter states that the compliance period for the proposed AD
should be extended from 9 months to one year. The commenter bases this
request on the fact that there are limited facilities available to
modify the FFG. The FAA does not concur. The manufacturer has
established sufficient inventory and facility capability to implement
the modification program within 9 months after the effective date of
the final rule AD. The FAA also notes that the burden on the current
inventory and facilities will be minimized because a large population
of operators have already voluntarily complied with the proposed FFG
modification.
One commenter states that the modification of the FFG, as required
by the proposed AD, on one engine for each aircraft, should be
sufficient for terminating action to AD 96-04-11, which required
selecting anti-ice prior to initiating descent. The FAA does not
concur. The FAA is concerned that under the circumstances in which a
rundown occurs, there could be excessive crew workload, and that this
increased workload could lead to potentially inappropriate actions by
the flight crew. The FAA has determined that the interests of the
flying public are best served by requiring the proposed FFG
modification on both engines to preclude this excessive crew workload.
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 with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 770 engines of the affected design in the
worldwide fleet. The FAA estimates that 381 engines installed on
aircraft of U.S. registry will be affected by this AD, that it will
take approximately 3 work hours per engine to accomplish the required
actions, and that the average labor rate is $60 per work hour. The
affected FFGs will be modified to incorporate the changes required by
this AD on a free-of-charge basis per engine. Based on these figures,
the total cost impact of the AD on U.S. operators is estimated to be
$68,580.
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 a Federalism Assessment.
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
[[Page 4900]]
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
97-02-12 Rolls-Royce plc: Amendment 39-9897. Docket 96-ANE-09.
Applicability: Rolls-Royce plc. (R-R) Models RB211-535E4 and -
535E4-B turbofan engines installed on Boeing 757-200 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 compressor stall and subsequent engine rundown on one
or both engines, accomplish the following:
(a) No later than 9 calendar months after the effective date of
this AD, install a fuel flow governor (FFG) that incorporates a
revised minimum compressor discharge P4 stop setting, in accordance
with R-R Mandatory Service Bulletin (SB) No. RB.211-73-B869,
Revision 1, dated May 24, 1996.
(b) Installation of improved FFGs on both engines for each
Boeing 757 aircraft in accordance with paragraph (a) of this AD
constitutes terminating action to the requirements of AD 96-04-11.
(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. The
request should be forwarded 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 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 following R-R Mandatory SB:
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Document No. Pages Revision Date
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RB.211-73-B869................ 1-4 1 May 24, 1996.
5-9 Original February 12,
1996.
Supplement.................... 1 Original February 12,
1996.
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Total Pages: 10.
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 Rolls-Royce plc, P.O. Box 31,
Moor Lane, Derby, DE248BJ, United Kingdom; telephone 1332-249428,
fax 1332-249423. 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 April 4, 1997.
Issued in Burlington, Massachusetts, on January 13, 1997.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 97-1701 Filed 1-31-97; 8:45 am]
BILLING CODE 4910-13-U
