[Federal Register: May 29, 2003 (Volume 68, Number 103)]
[Proposed Rules]
[Page 31994-31996]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29my03-25]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NM-27-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
Equipped With Pratt & Whitney JT9D-3 or JT9D-7 Series Engines (Except
JT9D-70 Series Engines)
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to Boeing Model 747 series airplanes
equipped with Pratt & Whitney JT9D-3 or JT9D-7 series engines (except
JT9D-70 series engines). This proposal would require detailed
inspections of the upper and lower surface of the forward lower spar of
the nacelle strut for cracking or other damage, and for any loose or
damaged fasteners. This proposal would also require replacement of
loose or damaged fasteners and, if necessary, associated repair of the
forward lower spar. This action is necessary to detect and correct
cracking or other damage to the upper or lower surface of the forward
lower spar and any loose or damaged fasteners, which could result in
reduced structural capability of nacelle struts one through four, and
possible separation of a strut and engine from the airplane during
flight. This action is intended to address the identified unsafe
condition.
DATES: Comments must be received by July 14, 2003.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 2002-NM-27-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:
9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must
contain ``Docket No. 2002-NM-27-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: Tamara Anderson, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425)
917-6421; fax (425) 917-6590.
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:
[sbull] 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.
[sbull] For each issue, state what specific change to the proposed
AD is being requested.
[sbull] 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
submitted in response to this action must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 2002-NM-27-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. 2002-NM-27-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
The FAA has received reports of multiple loose and damaged
fasteners and lower spar web damage of the No. 4 strut on two Boeing
Model 747 series airplanes equipped with Pratt & Whitney JT9D-7
engines. This damage was observed at approximately 1,900 and 2,900
flight cycles after incorporation of the strut modification described
in Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994.
That modification was made mandatory by AD 95-10-16, amendment 39-9233
(60 FR 27008, May 22, 1995). Analysis by Boeing indicates that the
loose fasteners were the result of incorrect installation of the
fasteners or the collars. Multiple loose fasteners allow out-of-plane
web deflection and damage to the lower spar web and fasteners. The
resulting damage could cause cracking and the loss of the lower spar.
This condition, if not corrected, could result in reduced structural
capability of the strut, and possible separation of the strut and
engine from the airplane during flight.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
747-54A2209, dated November 8, 2001, including Evaluation Form, which
describes procedures for the following actions:
Part 1: A detailed inspection of (a) the upper surface of the
forward lower spar for cracking and fretting damage to the web, forward
bulkhead channel, and stiffeners; and (b) the fasteners in that area
for missing heads, damage, and evidence of looseness, such as cracked
or broken sealant and fretting or galling around the collars, nuts, or
fastener heads.
Part 2: A detailed inspection of (a) the lower surface of the
forward lower spar for cracking and fretting damage to the web, c-
channel, chords, and stiffener; and (b) the fasteners in that area for
missing heads, damage, and evidence of
[[Page 31995]]
looseness, such as cracked or broken sealant and fretting or galling
around the collars, nuts, or fastener heads.
Part 3: Corrective action, which includes removing loose or damaged
fasteners, examining the fastener holes for damage or cracks using a
high frequency eddy current (HFEC) inspection, removing cracks or
damage by oversizing the holes, ensuring that all cracks and damage are
removed using a follow-up HFEC inspection, reaming the hole to a
minimum size, and installing a new fastener.
Boeing Alert Service Bulletin 747-54A2209, dated November 8, 2001,
also specifies that, if damage or cracking is found which cannot be
removed by oversizing a hole per the alert service bulletin, the Boeing
Company should be contacted for additional instructions.
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 require accomplishment of the actions specified in
the alert service bulletin described previously, except as discussed
below.
Differences Between Alert Service Bulletin and Proposed AD
Boeing Alert Service Bulletin 747-54A2209, dated November 8, 2001,
specifies that the manufacturer is to be contacted for disposition of
damage or cracks which cannot be repaired by oversizing a fastener hole
per the alert service bulletin. The proposed AD, however, would require
such repair to be accomplished 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.
Another difference involves inspection of the upper surface and the
lower surface of the forward lower spar. The alert service bulletin
recommends inspection of the upper surface after accumulation of 300
flight cycles since modification of the strut in accordance with AD 95-
10-16. Inspection of the lower surface is to be done after accumulation
of 1,300 flight cycles since modification. This proposed AD, however,
provides that, for airplanes which have accumulated 1,300 or more
flight cycles since modification of the strut, the initial inspection
may include both the upper surface and the lower surface of the forward
lower spar. If no damage is detected, no further action is required by
the AD.
Cost Impact
There are approximately 366 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 115 airplanes of U.S. registry
would be affected by this proposed AD, that it would take from 20 to 64
work hours per airplane to accomplish the proposed inspections, and
that the average labor rate is $60 per work hour. Based on these
figures, the cost impact of the proposed inspections is estimated to be
between $1,200 and $3,840 per airplane.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the proposed requirements of
this AD action, and that no operator would accomplish those actions in
the future if this proposed 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 adding the following new
airworthiness directive:
Boeing: Docket 2002-NM-27-AD.
Applicability: Model 747 series airplanes, equipped with Pratt &
Whitney JT9D-3 or JT9D-7 series engines (excluding JT9D-70 series
engines), as listed in Boeing Alert Service Bulletin 747-54A2209,
dated November 8, 2001; 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 (g) 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 detect and correct cracking or other damage to the structure
of the upper or lower surface of the forward lower spar and any
loose or damaged fasteners, which could result in reduced structural
capability of nacelle struts one through four, and possible
separation of the strut and engine from the airplane during flight,
accomplish the following:
Inspection of Upper Surface of Forward Lower Spar
(a) At the later of the times shown in paragraphs (a)(1) and
(a)(2) of this AD: Perform a detailed inspection of the upper
surface of the forward lower spar to detect cracks, fretting damage,
and any loose or damaged fasteners, in accordance with Part 1 of the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
54A2209, dated November 8, 2001, excluding Evaluation Form.
(1) Within 500 flight cycles, but no sooner than 300 flight
cycles, after modification of the strut in accordance with AD 95-10-
16, amendment 39-2933.
(2) Within 6 months after the effective date of this AD; or
[[Page 31996]]
Note 2: For the purposes of this AD, a detailed 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.''
Inspection of Lower Surface of Forward Lower Spar
(b) If the detailed inspection required by paragraph (a) of this
AD reveals any crack or fretting damage, or any loose or damaged
fastener: Prior to further flight, perform a detailed inspection of
the lower surface of the forward lower spar to detect cracks,
fretting damage, and any loose or damaged fasteners, in accordance
with Part 2 of the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-54A2209, dated November 8, 2001, excluding
Evaluation Form.
Follow-up Inspection
(c) If the detailed inspection of the upper surface of the
forward lower spar required by paragraph (a) of this AD reveals no
crack or fretting damage and no loose or damaged fastener: At the
later of the times specified in paragraphs (c)(1) and (c)(2) of this
AD, repeat the detailed inspection of the upper surface of the
forward lower spar and perform a detailed inspection of the lower
surface of the forward lower spar, in accordance with Parts 1 and 2,
respectively, of the Accomplishment Instructions of Boeing Alert
Service Bulletin 747-54A2209, dated November 8, 2001, excluding
Evaluation Form.
(1) Within 1,500 flight cycles, but no sooner than 1,300 flight
cycles, after modification of the strut, in accordance with AD 95-
10-16; or
(2) Within 18 months after the effective date of this AD.
Optional Follow-Up Inspection
(d) If the detailed inspection of the upper surface of the
forward lower spar required by paragraph (a) of this AD reveals no
crack or fretting damage, and no loose or damaged fastener: Prior to
further flight, the operator may elect to perform a detailed
inspection of the lower surface of the forward lower spar to detect
cracks, fretting damage, and any loose or damaged fasteners, in
accordance with Part 2 of the Accomplishment Instructions of Boeing
Alert Service Bulletin 747-54A2209, dated November 8, 2001,
excluding Evaluation Form, provided that the airplane has
accumulated at least 1,300 flight cycles since modification of the
strut per AD 95-10-16.
Corrective Action
(e) If any detailed inspection described in paragraph (a), (b),
(c), or (d) of this AD reveals any crack or fretting damage to the
upper or lower surface of the forward lower spar or any loose or
damaged fastener: Prior to further flight, accomplish the actions
specified in paragraph (e)(1) or (e)(2) of this AD, as applicable.
(1) If the crack or fretting damage to the upper or lower
surface of the forward lower spar falls within the parameters
specified in Figure 4 or 5 (as applicable) of the Accomplishment
Instructions of Boeing Alert Service Bulletin 747-54A2209, dated
November 8, 2001, excluding Evaluation Form, and the airplane has
accumulated 1,300 flight cycles or more since modification of the
strut per AD 95-10-16: Remove any loose or damaged fasteners, repair
any cracks or fretting damage to the upper or lower surface of the
forward lower spar, and install new fasteners, in accordance with
the Accomplishment Instructions of the service bulletin. No further
action is required by this AD.
(2) If the crack or fretting damage to the upper or lower
surface of the forward lower spar does not fall within the
parameters specified in Figure 4 or 5 (as applicable) of the
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
54A2209, dated November 8, 2001, excluding Evaluation Form, or if
the airplane has accumulated fewer than 1,300 flight cycles since
modification of the strut per AD 95-10-16: Accomplish additional
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 as required by this paragraph, the approval must
specifically reference this AD.
(f) If the detailed inspection specified in paragraph (c) or (d)
of this AD reveals no cracks or other damage to the upper or lower
surface of the forward lower spar and no loose or damaged fasteners,
no further action is required by this AD.
Alternative Methods of Compliance
(g) 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, FAA. 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.
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
(h) 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 May 22, 2003.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-13388 Filed 5-28-03; 8:45 am]
BILLING CODE 4910-13-P