[Federal Register Volume 59, Number 174 (Friday, September 9, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-21723]


[[Page Unknown]]

[Federal Register: September 9, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-16; Amendment 39-9016; AD 94-18-03]

 

Airworthiness Directives; Rolls-Royce plc RB211 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to Rolls-Royce plc (R-R) RB211 series turbofan engines. 
This action requires removing from service intermediate pressure (IP) 
compressor stage 6-7 rotor shafts that exceed new, reduced cyclic life 
limits. This amendment is prompted by a report of an uncontained 
failure of an IP compressor stage 6-7 rotor shaft. The actions 
specified in this AD are intended to prevent an uncontained engine 
failure due to rupture of an IP compressor stage 6-7 rotor shaft.

DATES: Effective September 26, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 26, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before November 8, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-16, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
Rolls-Royce plc, Technical Publications Department, P.O. Box 31, Derby, 
England. This information may be examined 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.

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: The Civil Aviation Authority (CAA), which is 
the airworthiness authority for the United Kingdom, recently notified 
the Federal Aviation Administration (FAA) that an unsafe condition may 
exist on Rolls-Royce plc (R-R) RB211-22B and -524 series turbofan 
engines. The CAA advises that they received a report of a cracked 
intermediate pressure (IP) compressor stage 6-7 rotor shaft that was 
removed from an R-R RB211-22B engine due to expiration of its life 
limit. The crack emanated from a corrosion pit, extending 0.45 inches 
radially inward from the bolt holes in the rotor shaft diaphragm. The 
manufacturer performed fracture mechanics analysis and determined that 
the rotor shaft would not reach its published life limit without 
cracking under normal operating conditions. Consequently, the CAA took 
mandatory action to reduce the life limit and remove suspect rotor 
shafts from service.
    The CAA received an additional report of an uncontained failure of 
an IP compressor stage 6-7 rotor shaft installed in an R-R RB211-22B 
engine that failed during takeoff roll. Investigation determined that 
the failure may have been caused by stress corrosion cracking of the 
tierod bolt holes. Laboratory examination revealed that the crack 
originated at a corrosion pit that had been present for, at minimum, 
two-thirds of the rotor shaft's service life. The investigation 
revealed additional rotor shafts with corrosion pitting and cracking. 
This condition, if not corrected, can result in an uncontained engine 
failure due to rupture of an IP compressor stage 6-7 rotor shaft.
    The R-R RB211-524 IP compressor stage 6-7 rotor shaft is similar in 
design and construction to the -22B, shares the same material 
composition, and has also exhibited bolt hole corrosion pitting and 
cracking. The -524 rotor shaft operates at higher stress levels than 
the -22B due to increased operational speeds.
    Rolls-Royce plc has issued Service Bulletin (SB) No. RB.211-72-
9594, Revision 5, dated February 12, 1993, that specifies rework of the 
IP compressor stage 6-7 rotor shaft; and SB No. RB.211-72-5787, dated 
March 20, 1981, that introduces a thicker IP compressor stage 6-7 rotor 
shaft. Rotor shafts complying with either of these SB's are not 
affected by this AD.
    This engine model is manufactured in the United Kingdom and is type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the CAA has kept the FAA informed of 
the situation described above. The FAA has examined the findings of the 
CAA, reviewed all available information, and determined that AD action 
is necessary for products of this type design that are certificated for 
operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other R-R RB.211 series turbofan engines of the 
same type design registered in the United States, this AD requires 
removing from service IP compressor stage 6-7 rotor shafts that exceed 
new, reduced cyclic life limits. This AD is not applicable to those 
engines that incorporate the thicker IP compressor stage 6-7 rotor 
shafts in accordance with R-R SB RB.211-72-5787, dated March 20, 1981. 
If operators elect to rework rotor shafts in accordance with R-R SB No. 
RB.211-72-9594, Revision 5, dated February 12, 1993, the rotor shafts 
may operate up to the assigned life limits.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 94-ANE-16.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

94-18-03 Rolls-Royce plc: Amendment 39-9016. Docket 94-ANE-16.

    Applicability: Rolls-Royce plc (R-R) Model RB211-22B and -524 
series turbofan engines, not incorporating thicker intermediate 
pressure (IP) compressor stage 6-7 rotor shafts in accordance with 
R-R Service Bulletin (SB) RB.211-72-5787, dated March 20, 1981, and 
incorporating IP compressor stage 6-7 rotor shafts that have not 
been reworked in accordance with R-R SB RB.211-72-9594, Revision 5, 
dated February 12, 1993. These engines are installed on but not 
limited to Boeing 747 series and 767 series, and Lockheed L-1011 
series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained engine failure due to rupture of an IP 
compressor stage 6-7 rotor shaft, accomplish the following:
    (a) For R-R RB211-22B series engines, accomplish the following:
    (1) For IP compressor stage 6-7 rotor shafts that have greater 
than or equal to 14,000 cycles in service (CIS) on the effective 
date of this AD, remove the rotor shafts within 15 days after the 
effective date of this AD, and replace with a serviceable part.
    (2) For IP compressor stage 6-7 rotor shafts that have less than 
14,000 CIS but greater than 11,000 CIS on the effective date of this 
AD, remove the rotor shafts at the next shop visit, or prior to 45 
days after the effective date of this AD, whichever occurs first, 
and replace with a serviceable part.
    (3) For IP compressor stage 6-7 rotor shafts that have 11,000 or 
less CIS on the effective date of this AD, remove the rotor shafts 
on or before 11,000 CIS, or 45 days after the effective date of this 
AD, whichever occurs later, and replace with a serviceable part.
    (4) Subsequent to 45 days after the effective date of this AD, 
the new life limit for the IP compressor stage 6-7 rotor shafts that 
have not been reworked in accordance with R-R SB RB.211-72-9594, 
Revision 5, dated February 12, 1993, shall be 11,000 CIS.
    (5) Rotor shafts that are reworked in accordance with R-R 
Service Bulletin No. RB.211-72-9594, Revision 5, dated February 12, 
1993, may remain in service until their assigned life limits are 
reached.
    (b) For all affected R-R RB211-524 series engines excluding R-R 
Models RB211-524D4, -524G, and -524H, accomplish the following:
    (1) For IP compressor stage 6-7 rotor shafts that have greater 
than or equal to 10,500 CIS on the effective date of this AD, remove 
the rotor shafts within 15 days after the effective date of this AD, 
and replace with a serviceable part.
    (2) For IP compressor stage 6-7 rotor shafts that have less than 
10,500 CIS but greater than 7,500 CIS on the effective date of this 
AD, remove the rotor shafts at the next shop visit, or January 31, 
1995, whichever occurs first, and replace with a serviceable part.
    (3) For IP compressor stage 6-7 rotor shafts that have 7,500 or 
less CIS on the effective date of this AD, remove the rotor shafts 
on or before 7,500 CIS, or January 31, 1995, whichever occurs later, 
and replace with a serviceable part.
    (4) After January 31, 1995, the new life limit for the IP 
compressor stage 6-7 rotor shafts that have not been reworked in 
accordance with R-R SB RB.211-72-9594, Revision 5, dated February 
12, 1993, shall be 7,500 CIS.
    (5) Rotor shafts that are reworked in accordance with R-R 
Service Bulletin No. RB.211-72-9594, Revision 5, dated February 12, 
1993, may remain in service until their assigned life limits are 
reached.
    (c) For R-R Models RB211-524D4, -524G, and -524H engines, and 
all other models of R-R RB211-524 series engines with the thicker IP 
compressor stage 6-7 rotor shaft in accordance with R-R SB RB.211-
72-5787, dated March 20, 1981, accomplish the following:
    (1) For IP compressor stage 6-7 rotor shafts that have greater 
than or equal to 10,500 CIS on the effective date of this AD, remove 
the rotor shafts within 15 days after the effective date of this AD, 
and replace with a serviceable part.
    (2) For IP compressor stage 6-7 rotor shafts that have less than 
10,500 CIS but greater than 8,500 CIS on the effective date of this 
AD, remove the rotor shafts at the next shop visit, or January 31, 
1995, whichever occurs first, and replace with a serviceable part.
    (3) For IP compressor stage 6-7 rotor shafts that have 8,500 or 
less CIS on the effective date of this AD, remove the rotor shafts 
on or before 8,500 CIS, or January 31, 1995, whichever occurs later, 
and replace with a serviceable part.
    (4) After January 31, 1995, the new life limit for the IP 
compressor stage 6-7 rotor shafts shall be 8,500 CIS.
    (5) Rotor shafts that are reworked in accordance with R-R 
Service Bulletin No. RB.211-72-9594, Revision 5, dated February 12, 
1993, may remain in service until their assigned life limits are 
reached.
    (d) 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: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (e) 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.
    (f) The rework, if accomplished, shall be done in accordance 
with the following service documents: 

----------------------------------------------------------------------------------------------------------------
                   Document No.                          Pages          Revision                 Date           
----------------------------------------------------------------------------------------------------------------
R-R SB No. RB.211-72-9594..........................  1............  5...............  February 12, 1993.        
                                                     2............  Original........  February 5, 1992.         
                                                     3............  4...............  November 13, 1992.        
                                                     4............  2...............  May 8, 1992.              
                                                     5............  4...............  November 13, 1992.        
                                                     6-6A.........  2...............  May 8, 1992.              
                                                     7............  Original........  February 5, 1992.         
                                                     8-9..........  2...............  May 8, 1992.              
                                                     10...........  3...............  August 7, 1992.           
                                                     11-14........  2...............  May 8, 1992.              
                                                     15-18........  Original........  February 5, 1992.         
                                                     19-20........  4...............  November 13, 1992.        
                                                     21...........  Original........  February 5, 1992.         
                                                     22-25........  2...............  May 8, 1992.              
Supplement.........................................  1............  2...............  May 8, 1992.              
Appendix 1.........................................  1-4..........  5...............  February 12, 1993.        
                                                     5............  Original........  February 5, 1992.         
Total pages: 32.                                                                                                
R-R SB No. RB.211-72-5787..........................  1-6..........  Original........  March 20, 1981.           
Supplement.........................................  1............  Original........  March 20, 1981.           
Total pages: 7.                                                                                                 
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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 Rolls-Royce plc, Technical 
Publications Department, P.O. Box 31, Derby, England. 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.
    (g) This amendment becomes effective on September 26, 1994.

    Issued in Burlington, Massachusetts, on August 24, 1994.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 94-21723 Filed 9-8-94; 8:45 am]
BILLING CODE 4910-13-P