[Federal Register Volume 64, Number 232 (Friday, December 3, 1999)]
[Proposed Rules]
[Pages 67806-67807]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31436]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-33-AD]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce, plc RB211 Trent 875, 877, 
884, 892, 892B 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 an existing 
airworthiness directive (AD), applicable to certain Rolls-Royce, plc 
RB211 Trent 800 series turbofan engines, that currently requires 
initial and repetitive ultrasonic inspections of fan blade roots for 
cracks, and replacement, if necessary, with serviceable parts. This 
proposed action would reduce initial cyclic compliance threshold and 
repetitive inspection intervals. This proposal would also allow 
inspections to be accomplished within 100 cycles-in-service if the 
initial or repetitive thresholds are exceeded on the effective date of 
the AD. This proposal is prompted by an improved understanding of the 
crack propagation mechanism and the latest service operational data. 
The actions specified by the proposed AD are intended to prevent fan 
blade failure, which could result in multiple fan blade releases, 
uncontained engine failure, and possible damage to the airplane.

DATES: Comments must be received by February 1, 2000.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-ANE-33-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299. Comments may also be sent via the Internet 
using the following address: ``[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 Rolls-Royce North America, Inc., 2001 South Tibbs Ave., 
Indianapolis, IN 46241; telephone (317) 230-3995, fax (317) 230-4743. 
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: Jason Yang, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7747, fax (781) 238-7199.

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 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 98-ANE-33-AD.'' 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. 98-ANE-33-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On September 11, 1998, the Federal Aviation Administration (FAA) 
issued airworthiness directive 98-19-21, Amendment 39-10762 (63 FR 
50484, September 22, 1998, corrected by 63 FR 52961, October 2, 1998), 
applicable to Rolls-Royce, plc (R-R) RB211 Trent 800 series turbofan 
engines, to require initial and repetitive ultrasonic inspections of 
fan blade roots for cracks, and replacement, if necessary, with 
serviceable parts. That action was prompted by reports of multiple fan 
blade root cracks in several factory test engines. That condition, if 
not corrected, could result in fan blade failure, which could result in 
multiple fan blade releases, uncontained engine failure, and possible 
damage to the airplane.

Information since Publication of AD 98-19-21

    Since the issuance of that AD, the Civil Aviation Authority (CAA) 
of the United Kingdom and the FAA have received revised analysis from 
the manufacturer and recent service data from operators. R-R's analysis 
provides an improved understanding of the crack propagation mechanism 
and the service operational data since institution of the inspection 
program required by the current AD indicates that the initial 
compliance threshold and repetitive inspection intervals must be 
decreased in order to maintain an acceptable level of safety.

Service Bulletin (SB)

    R-R has issued SB RB211-72-C445, Revision 6, dated September 3, 
1999, that describes the initial inspection threshold and repetitive 
inspection intervals for Trent 800 series turbofan engines. The SB also 
describes the procedures for ultrasonic inspections of fan blade roots 
for cracks, and provides part rejection data.

[[Page 67807]]

Proposed Actions

    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 AD 98-19-21 to reduce initial compliance 
thresholds and repetitive cyclic inspection intervals. This proposal 
would also allow inspections to be accomplished within 100 cycles-in-
service if the initial or repetitive thresholds are exceeded on the 
effective date of the AD. The actions would be required to be 
accomplished in accordance with the SB listed above.

Economic Analysis

    The FAA estimates that 24 engines installed on aircraft of US 
registry would be affected by this proposed AD, that it would take 
approximately 8 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Based on 
these figures, the total cost impact of the proposed AD on US operators 
is estimated to be $11,520.

Regulatory Impact

    This proposal does not have federalism implications, as defined in 
Executive Order No. 13132, because it would not have a substantial 
direct effect 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this proposal.
    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 39-10762 (63 FR 
50484, September 22, 1998) and by adding a new airworthiness directive 
to read as follows:

    Rolls-Royce, plc: Docket No. 98-ANE-33-AD. Supersedes AD 98-19-
21, Amendment 39-10762.

    Applicability: Rolls-Royce, plc (R-R) RB211 Trent 875, RB211 
Trent 877, RB211 Trent 884, RB211 Trent 892, and Trent 892B series 
turbofan engines, except if the fan blades described in R-R Service 
Bulletin (SB) RB211-72-C629 were installed as complete sets. These 
engines are installed on but not limited to Boeing 777 series 
airplanes.

    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 (b) 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 fan blade failure, which could result in multiple fan 
blade releases, uncontained engine failure, and possible damage to 
the airplane, accomplish the following:

Ultrasonic Inspections (Reduced Thresholds and Repetitive Intervals)

    (a) Perform initial and repetitive inspections of fan blade 
roots for cracks, in accordance with R-R SB No. RB211-72-C445, 
Revision 6, dated September 3, 1999, as follows:
    (1) For Trent 875 series engines, as follows:
    (i) Initially inspect prior to accumulating 3,000 cycles-since-
new (CSN).
    (ii) Thereafter, inspect at intervals not to exceed 400 cycles-
in-service (CIS) since last inspection.
    (2) For Trent 877 series engines, as follows:
    (i) Initially inspect prior to accumulating 2,000 CSN.
    (ii) Thereafter, inspect at intervals not to exceed 350 CIS 
since last inspection.
    (3) For Trent 884 series engines, as follows:
    (i) Initially inspect prior to accumulating 1,500 CSN.
    (ii) Thereafter, inspect at intervals not to exceed 350 CIS 
since last inspection.
    (4) For Trent 892 and 892B series engines, as follows:
    (i) Initially inspect prior to accumulating 900 CSN.
    (ii) Thereafter, inspect at intervals not to exceed 200 CIS 
since last inspection.

Engines Exceeding Thresholds and Repetitive Intervals

    (5) For engines that exceed the initial inspection thresholds 
listed in paragraphs (a)(1)(i), (a)(2)(i), (a)(3)(i), and (a)(4)(i) 
on the effective date of this AD, conduct initial inspection within 
100 CIS after the effective date of this AD.
    (6) For engines that exceed the repetitive inspection intervals 
listed in paragraphs (a)(1)(ii), (a)(2)(ii), (a)(3)(ii), and 
(a)(4)(ii) on the effective date of this AD, inspect within 100 CIS 
after the effective date of this AD.

Cracked Parts

    (7) Prior to further flight, remove from service cracked fan 
blades and replace with serviceable parts.

Alternate Method of Compliance

    (b) 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 (ECO). 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the ECO.

Ferry Flights

    (c) Special flight permits may be issued in accordance with 
Secs. 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 
inspection requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on November 29, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-31436 Filed 12-2-99; 8:45 am]
BILLING CODE 4910-13-U