[Federal Register Volume 67, Number 3 (Friday, January 4, 2002)]
[Proposed Rules]
[Pages 547-550]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-208]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-376-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped with Rolls Royce RB211 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 Boeing Model 757 
series airplanes equipped with Rolls Royce RB211 engines, that 
currently requires modification of the nacelle strut and wing 
structure. This action would add a one-time inspection of the middle 
gusset of the inboard side load fitting for proper alignment, and a 
one-time inspection of certain fastener holes in the lower spar fitting 
of the nacelle strut and wing structure for cracking, and corrective 
actions, if necessary. For certain airplanes, this action would require 
installation of new fasteners. The actions specified by the proposed AD 
are intended to prevent fatigue cracking in primary strut structure and 
consequent reduced structural integrity of the strut. These actions are 
intended to address the identified unsafe condition.

DATES: Comments must be received by February 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-376-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-376-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2776; fax (425) 227-1181.

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 shall identify the Rules Docket number 
and be submitted in triplicate 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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

[[Page 548]]

submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-376-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, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 2000-NM-376-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On November 17, 1999, the FAA issued AD 99-24-07, amendment 39-
11431 (64 FR 66370, November 26, 1999), applicable to certain Boeing 
Model 757 series airplanes equipped with Rolls Royce RB211 engines, to 
require modification of the nacelle strut and wing structure. That 
action was prompted by reports indicating that the actual operational 
loads applied to the nacelle are higher than the analytical loads that 
were used during the initial design. Such an increase in loading can 
lead to fatigue cracking in primary strut structure prior to an 
airplane's reaching its design service objective. The requirements of 
that AD are intended to prevent fatigue cracking in primary strut 
structure and consequent reduced structural integrity of the strut.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 99-24-07, the FAA has reviewed and 
approved Boeing Service Bulletin 757-54-0035, Revision 1, dated April 
15, 1999. The procedures in this service bulletin are similar to those 
in Boeing Service Bulletin 757-54-0035, dated July 17, 1997, which was 
referenced as the appropriate source of service information for the 
modification of the nacelle strut and wing structure required by the 
existing AD. However, Revision 1 describes new procedures for an 
examination of the middle gusset of the inboard side load fitting to 
determine if the angle between the middle gusset and the outboard face 
of the lug is out of alignment. If the angle is out of alignment, the 
corrective action involves machining the middle gusset to the specified 
angle.
    Revision 1 also describes procedures for removing and discarding 
the midchord and aft bulkhead fasteners of the lower spar fitting, and 
doing a one-time eddy current inspection of those fastener holes for 
cracking. If any indication of a crack is found, the service bulletin 
specifies contacting the airplane manufacturer for repair instructions. 
The service bulletin also describes procedures to increase the diameter 
of the fastener holes and install new, improved fasteners. For 
airplanes modified per the original issue of the service bulletin, 
these new procedures are described separately in Part V of Revision 1. 
Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    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 99-24-07 to continue to require 
modification of the nacelle strut and wing structure. This action would 
add a one-time inspection of the middle gusset of the inboard side load 
fitting for proper alignment, and corrective action, if necessary; and 
a one-time inspection of the lower spar fitting of the nacelle strut 
and wing structure for cracking, and enlargement of the holes and 
replacement of certain fasteners with new, improved fasteners. The 
actions would be required to be accomplished according to the service 
bulletin described previously, except as discussed below.

Differences Between Proposed AD and Service Bulletin

    Although the service bulletin specifies that the manufacturer may 
be contacted for disposition of certain repairs, this proposed AD would 
require such repairs to be accomplished per a method approved by the 
FAA, or per data meeting the type certification basis of the airplane 
approved by a Boeing Company Designated Engineering Representative who 
has been authorized by the Manager, Seattle Aircraft Certification 
Office, to make such findings.
    This proposed AD requires accomplishment of the inspections within 
3 years after accomplishment of the modification of the nacelle strut 
and wing structure, or 3 years after the effective date of this AD, 
whichever is later. The service bulletin recommends that operators 
accomplish the actions in the bulletin ``at a maintenance time when the 
engines are removed, but before the airplane gets 50,000 total flight 
cycles.'' In developing an appropriate compliance time for this AD, the 
FAA considered not only the manufacturer's recommendation, but the 
degree of urgency associated with addressing the subject unsafe 
condition, the average utilization of the affected fleet, and the time 
necessary to perform the inspections (1 hour for detailed visual/8 
hours for fastener removal/eddy current). In light of all of these 
factors, the FAA finds a 3-year compliance time for initiating the 
inspections to be warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.
    Although the service bulletin specifies an examination of the 
middle gusset of the inboard side load fitting for proper alignment, 
this proposed AD would require a detailed visual inspection for 
accomplishment of that action. A note has been included in this 
proposed rule to define that inspection.

Cost Impact

    There are approximately 394 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 176 airplanes of U.S. registry 
would be affected by this proposed AD.
    The modification that is currently required by AD 99-24-07 takes 
approximately 1,049 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. This work hour figure includes 
the time it will take to remove and reinstall the struts from the 
airplane as well as the time to gain and close access to the adjacent 
wing structure. Based on these figures, the cost impact of the 
currently required modification on U.S. operators is estimated to be 
$11,077,440, or $62,940 per airplane.
    This cost impact figure does not reflect the cost of the 
terminating actions described in the service bulletins listed in 
paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 6 of 
Boeing Service Bulletin 757-54-0035, that are required to be 
accomplished prior to, or concurrently with, the modification of the 
nacelle strut and wing structure. Since some operators may have 
accomplished certain modifications on some or all of the airplanes in 
its fleet, while other operators may not have accomplished any of the 
modifications on any of the airplanes in its fleet, the FAA is unable 
to provide a reasonable estimate of the cost of accomplishing the 
terminating actions described in the service bulletins listed in Table 
I of the service bulletin.
    It would take approximately 1 work hour per airplane to accomplish 
the new detailed visual inspection of the middle gusset, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the inspection proposed by this AD on U.S. operators is 
estimated to be $60 per airplane.

[[Page 549]]

    It would take approximately 8 work hours per airplane to accomplish 
the new fastener removal and eddy current inspection, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the removal and inspection proposed by this AD on U.S. 
operators is estimated to be $480 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted. The cost 
impact figures discussed in AD rulemaking actions represent only the 
time necessary to perform the specific actions actually required by the 
AD. These figures typically do not include incidental costs, such as 
the time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

Regulatory Impact

    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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 39-11431 (64 FR 
66370, November 26, 1999), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2000-NM-376-AD. Supersedes AD 99-24-07, Amendment 39-
11431.

    Applicability: Model 757 series airplanes equipped with Rolls 
Royce engines, line numbers 1 through 735 inclusive; certificated in 
any category.

    Note 1: This AD applies to each airplane 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 airplanes 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)(1) 
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 fatigue cracking in primary strut structure and 
consequent reduced structural integrity of the strut, accomplish the 
following:

Restatement of Requirements of AD 99-24-07

Modification

    (a) Modify the nacelle strut and wing structure according to 
Boeing Service Bulletin 757-54-0035, dated July 17, 1997, or 
Revision 1, dated April 15, 1999, at the later of the times 
specified in paragraph (a)(1) or (a)(2) of this AD. All of the 
terminating actions described in the service bulletins listed in 
paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 6 
of Boeing Service Bulletin 757-54-0035, or on page 7 of Revision 1 
of the service bulletin, as applicable, must be accomplished 
according to those service bulletins prior to, or concurrently with, 
the accomplishment of the modification of the nacelle strut and wing 
structure required by this paragraph. After the effective date of 
this AD, use only Revision 1 of the service bulletin.
    (1) Prior to the accumulation of 37,500 total flight cycles, or 
prior to 20 years since the date of manufacture of the airplane, 
whichever occurs first.
    (2) Within 3,000 flight cycles after January 3, 2000 (the 
effective date of AD 99-24-07, amendment 39-11431).

New Requirements of This AD

One-Time Inspections/Corrective Actions

    (b) For airplanes that have done the modification required by 
paragraph (a) of this AD according to Boeing Service Bulletin 757-
54-0035, dated July 17, 1997: Within 3 years after doing the 
modification required by paragraph (a) of this AD, or 3 years after 
the effective date of this AD, whichever is later, do the 
requirements specified in paragraphs (b)(1) and (b)(2) of this AD.
    (1) Do a one-time detailed visual inspection of the middle 
gusset of the inboard side load fitting for proper alignment 
according to Part II of the Accomplishment Instructions of Boeing 
Service Bulletin 757-54-0035, Revision 1, dated April 15, 1999. If 
the gusset is not aligned properly, before further flight, machine 
the gusset to the specified angle, according to the service 
bulletin.


    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''


    (2) Remove and discard the midchord and aft bulkhead fasteners 
of the lower spar fitting and do a one-time eddy current inspection 
of those fastener holes for cracking according to Part V of the 
Accomplishment Instructions of Boeing Service Bulletin 757-54-0035, 
Revision 1, dated April 15, 1999.
    (i) If any cracking is found during the inspection required by 
paragraph (b)(2) of this AD: Before further flight, repair per a 
method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or per data meeting the type certification basis 
of the airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the Manager, Seattle ACO, 
to make such findings. For a repair method to be approved by the 
Manager, Seattle ACO, as required by this paragraph, the Manager's 
approval letter must specifically reference this AD. Then do 
paragraph (b)(2)(ii) of this AD.
    (ii) If no cracking is found during the inspection required by 
paragraph (b)(2) of this AD, or after repair of cracking as required 
by paragraph (b)(2)(i) of this AD: Before further flight, increase 
the diameter of the fastener holes and install new fasteners, 
according to the service bulletin.

Alternative Methods of Compliance

    (c)(1) 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, Seattle ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Seattle ACO.

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    (2) Alternative methods of compliance, approved previously in 
accordance with AD 99-24-07, amendment 39-11431, are approved as 
alternative methods of compliance with paragraph (a) of this AD.


    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (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.

    Issued in Renton, Washington, on December 28, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-208 Filed 1-3-02; 8:45 am]
BILLING CODE 4910-13-P