[Federal Register Volume 66, Number 32 (Thursday, February 15, 2001)]
[Proposed Rules]
[Pages 10387-10390]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-3857]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-330-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Powered By Pratt & Whitney JT9D-3 and -7 Series Engines

AGENCY: Federal Aviation Administration, DOT.

[[Page 10388]]


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 747 
series airplanes, that currently requires repetitive inspections and 
torque checks of the hanger fittings and strut forward bulkhead of the 
forward engine mount and adjacent support structure, and corrective 
actions, if necessary. The existing AD also provides for optional 
terminating action for the repetitive inspections and checks. This 
action would mandate certain new repetitive torque checks and the 
previously optional terminating action. The actions specified by the 
proposed AD are intended to prevent loose fasteners and associated 
damage to the hanger fittings and bulkhead of the forward engine mount, 
which could result in separation of the engine from the airplane.

DATES: Comments must be received by April 2, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-330-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: 
<a href="/cdn-cgi/l/email-protection#9fa6b2fef1f2b2f1efedf2fcf0f2f2faf1ebdff9fefeb1f8f0e9"><span class="__cf_email__" data-cfemail="172e3a76797a3a7967657a74787a7a7279635771767639707861">[email protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-330-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) 
227-2771; 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:
    <bullet> 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.
    <bullet> For each issue, state what specific change to the proposed 
AD is being requested.
    <bullet> 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 2000-NM-330-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-330-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On November 8, 2000, the FAA issued AD 2000-23-16, amendment 39-
11988 (65 FR 69862, November 21, 2000), applicable to certain Boeing 
Model 747 series airplanes, to require repetitive inspections and 
torque checks of the hanger fittings and strut forward bulkhead of the 
forward engine mount and adjacent support structure, and corrective 
actions, if necessary. (On December 21, 2000, a correction to that AD 
was published in the Federal Register (65 FR 80301).) That action also 
provides for optional terminating action for the repetitive inspections 
and checks. That action was prompted by reports indicating the 
detection of loose fasteners of the hanger fittings and strut forward 
bulkhead of the forward engine mount. The requirements of that AD are 
intended to detect and correct loose fasteners and associated damage to 
the hanger fittings and bulkhead of the forward engine mount, which 
could result in separation of the engine from the airplane.

Actions Since Issuance of Previous Rule

    In the preamble to AD 2000-23-16, the FAA indicated that the 
actions required by that AD were considered ``interim action'' and that 
it was considering a separate rulemaking action to mandate 
accomplishment of the terminating action described in Part 6 of Boeing 
Alert Service Bulletin 747-54A2203, dated August 31, 2000, which would 
terminate the repetitive inspections and checks required by that AD. 
The FAA also indicated that it was considering mandating the torque 
checks described in Part 3 of the alert service bulletin. The FAA now 
has determined that further rulemaking action is indeed necessary, and 
this proposed AD follows from that determination.

Explanation of Relevant Service Information

    The FAA previously reviewed and approved Boeing Alert Service 
Bulletin 747-54A2203, dated August 31, 2000, which describes procedures 
for repetitive detailed visual inspections and torque checks of the 
hanger fittings and strut forward bulkhead of the forward engine mount 
and adjacent support structure to detect loose fasteners, cracking, 
and/or damage; and corrective actions, if necessary. The corrective 
actions consist of a torque check, before further flight, if any loose 
fasteners are detected; rework of loose hanger fittings and damaged or 
cracked fittings that are within the allowable rework limits; and 
replacement if damage or cracks are detected that are outside the 
allowable rework limits.
    If certain damage of the strut forward bulkhead, bulkhead chords, 
lower spar web, or bulkhead channel is detected, the alert service 
bulletin specifies contacting Boeing for rework/replacement 
instructions. The alert service bulletin also describes procedures for 
a terminating action, which eliminates the need for the repetitive 
inspections and checks. The

[[Page 10389]]

terminating action involves rework or replacement of the fittings.

Explanation of Requirements of Proposed AD

    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 2000-23-16 to continue to require 
repetitive inspections and torque checks of the hanger fittings and 
strut forward bulkhead of the forward engine mount and adjacent support 
structure, and corrective actions, if necessary. This proposed AD would 
mandate certain new repetitive torque checks and the previously 
optional terminating action. The actions would be required to be 
accomplished in accordance with the alert service bulletin described 
previously, except as discussed below.

Differences Between Alert Service Bulletin and This Proposed AD

    Operators should note that, although the effectivity section of the 
alert service bulletin includes Boeing Model 747 series airplanes 
having serial numbers 21048 and 20887, these airplanes have been 
modified and are now powered by General Electric CF6-50 series engines, 
and are not affected by the actions required by this proposed rule.
    Operators also should note that, although the alert service 
bulletin specifies that the manufacturer may be contacted for certain 
rework and/or replacement instructions, this AD requires such rework 
and/or replacement to be done in accordance with a method approved by 
the FAA, or in accordance with data meeting the type certification 
basis of the airplane approved by a Boeing Company Designated 
Engineering Representative who has been authorized by the FAA to make 
such findings.

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.
    The detailed visual inspections that are currently required by AD 
2000-23-16 take approximately 8 work hours per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of the inspections currently required by the existing 
AD on U.S. operators is estimated to be $55,200, or $480 per airplane, 
per inspection.
    The torque checks that are currently required by AD 2000-23-16 take 
approximately 24 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the torque checks currently required by the existing AD on 
U.S. operators is estimated to be $165,600, or $1,440 per airplane, per 
check.
    The new torque checks proposed in this AD action also would take 
approximately 8 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of this torque check on U.S. operators is estimated to be 
$55,200, or $480 per airplane, per check.
    The terminating action proposed in this AD action would take 
approximately 24 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would cost 
approximately $300 per airplane. Based on these figures, the cost 
impact of the terminating action proposed by this AD on U.S. operators 
is estimated to be $200,100, or $1,740 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 39-11988 (65 FR 
80301, December 21, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2000-NM-330-AD. Supersedes AD 2000-23-16, Amendment 
39-11988.

    Applicability: Model 747 series airplanes, certificated in any 
category, as listed in Boeing Alert Service Bulletin 747-54A2203, 
dated August 31, 2000; except Model 747 series airplanes having 
serial numbers 21048 and 20887.

    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 (d) 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 loose fasteners and associated damage to the hanger 
fittings and strut forward bulkhead of the forward engine mount, 
which could result in separation of the engine from the airplane, 
accomplish the following:

Restatement of Requirements of AD 2000-23-16

Repetitive Inspections/Checks

    (a) Within 60 days after December 6, 2000 (the effective date of 
AD 2000-23-16, amendment 39-11988): Perform a detailed visual 
inspection and torque check as

[[Page 10390]]

specified in Part 2 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-54A2203, dated August 31, 2000, to detect 
loose fasteners and associated damage to the hanger fittings and 
bulkhead of the forward engine mount, in accordance with Figure 1 of 
the alert 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.''

    (1) If no loose fastener or associated damage is detected, 
repeat the inspections/checks thereafter at the applicable intervals 
specified in Figure 1 of the alert service bulletin until 
accomplishment of the terminating action specified in paragraph (c) 
of this AD.

    Note 3: Where there are differences between the AD and the alert 
service bulletin, the AD prevails.

Corrective Actions

    (2) If any loose fastener or associated damage is detected, 
before further flight, perform the applicable corrective actions 
(torque check, rework or replacement of fittings), as specified in 
Figure 1 of the alert service bulletin. Repeat the inspections/
checks thereafter at the applicable intervals specified in Figure 1 
of the alert service bulletin until accomplishment of the 
terminating action specified in paragraph (c) of this AD. Where the 
alert service bulletin specifies that the manufacturer may be 
contacted for disposition of certain corrective actions (rework or 
replacement of fittings), this AD requires such rework and/or 
replacement to be done in accordance with a method approved by the 
Manager, Seattle Aircraft Certification Office (ACO), FAA; or in 
accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company designated engineering 
representative (DER) 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.

New Requirements of This AD

Repetitive Checks/Inspections/Corrective Actions

    (b) Within 18 months after the effective date of this AD: Do the 
torque check specified in Part 3 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 747-54A2203, dated August 31, 2000, 
to detect loose fasteners of the hanger fittings of the forward 
engine mount.
    (1) If no loose fastener is detected, repeat the torque check 
thereafter at intervals not to exceed 1,200 flight cycles or 18 
months, whichever occurs first, until accomplishment of the 
terminating action specified in paragraph (c) of this AD.
    (2) If any loose fastener is detected, before further flight, 
perform the applicable corrective actions as specified in Figure 4, 
Figure 5, or Part 6, as applicable, of the Accomplishment 
Instructions of the alert service bulletin.
    (i) If Figure 4 or Figure 5 of the Accomplishment Instructions 
of the alert service bulletin is used to do the corrective actions 
for the fitting; thereafter, repeat the detailed visual inspection 
required by paragraph (a) of this AD at the applicable intervals 
specified in Figure 1 of the alert service bulletin, and repeat the 
torque check for that fitting at intervals not to exceed 180 flight 
cycles. Accomplish the terminating action for that fitting as 
specified in Part 6 of the Accomplishment Instructions of the alert 
service bulletin within 18 months after finding any loose fastener 
or 60 months after the effective date of this AD, whichever occurs 
first.
    (ii) If Part 6 of the Accomplishment Instructions of the alert 
service bulletin is used to do the corrective actions for the 
fitting, this constitutes terminating action for the repetitive 
inspections/checks for that fitting only.
    (3) If any associated damage is found, before further flight, 
repair in accordance with a method approved by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA; or in accordance with data 
meeting the type certification basis of the airplane approved by a 
Boeing Company designated engineering representative (DER) 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. If any damage to any fitting is 
found, before further flight, do the applicable corrective actions 
specified in Part 4 or Part 5 of the Accomplishment Instructions of 
the alert service bulletin; this constitutes terminating action for 
the repetitive inspections/checks for that fitting only.
    (4) If any loose fastener is detected during any repeat 
inspection/check specified in paragraph (b)(2)(i) of this AD, before 
further flight, accomplish the terminating action for that fitting 
as specified in Part 6 of the Accomplishment Instructions of the 
alert service bulletin.

Terminating Action

    (c) Within 60 months after the effective date of this AD: 
Accomplish all actions in the terminating action specified in Part 6 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
747-54A2203, dated August 31, 2000. Accomplishment of this paragraph 
constitutes terminating action for the repetitive inspections/checks 
required by paragraphs (a) and (b) of this AD. Where the alert 
service bulletin specifies that the manufacturer may be contacted 
for disposition of certain corrective actions (rework or replacement 
of fittings), this AD requires such rework and/or replacement to be 
done in accordance with a method approved by the Manager, Seattle 
ACO; or in accordance with data meeting the type certification basis 
of the airplane approved by a Boeing Company DER 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.

    Note 4: Installation of two BACW10BP*APU washers on Group A 
fasteners accomplished during modification in accordance with Boeing 
Service Bulletin 747-54A2159, dated November 3, 1994, Revision 1, 
dated June 1, 1995, or Revision 2, dated March 14, 1996; and pin or 
bolt protrusion as specified in the 747 Structural Repair Manual, 
Chapter 51-30-02 (both referenced in Boeing Alert Service Bulletin 
747-54A2203, dated August 31, 2000); is considered acceptable for 
compliance with the terminating action specified in paragraph (c) of 
this AD.

Alternative Methods of Compliance

    (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, 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.

    Note 5: 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

    (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 airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on February 9, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-3857 Filed 2-14-01; 8:45 am]
BILLING CODE 4910-13-U


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