AD 2001-12-05

[Federal Register Volume 66, Number 113 (Tuesday, June 12, 2001)]
[Rules and Regulations]
[Pages 31527-31530]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-14533]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-118-AD; Amendment 39-12260; AD 2001-12-05]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-200, 747-300, 
and 747SR Series Airplanes Powered by General Electric CF6-45/50 and 
Pratt & Whitney JT9D-70 Series 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 certain Boeing Model 747-100, 747-200, 747-300, and 
747SR series airplanes powered by General Electric CF6-45/50 and Pratt 
& Whitney JT9D-70 series engines. This action requires a detailed 
visual inspection of the outboard diagonal brace for heat damage and 
cracking; and follow-on repetitive inspections or corrective actions, 
if necessary. This action also provides an optional terminating action 
for the requirements of this AD. This action is necessary to detect and 
correct heat damage to the diagonal brace, which could cause cracking 
or fracture of the diagonal brace, and possible loss of the diagonal 
brace load path and consequent separation of the strut and engine from 
the airplane.

DATES: Effective June 27, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 27, 2001.
    Comments for inclusion in the Rules Docket must be received on or 
before August 13, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-118-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#11283c707f7c3c787063727e7c7c747f65517770703f767e67"><span class="__cf_email__" data-cfemail="8cb5a1ede2e1a1e5edfeefe3e1e1e9e2f8cceaededa2ebe3fa">[email&#160;protected]</span></a>. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-118-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 this AD 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; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tamara L. 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: The FAA has received reports from two 
operators who found heat damage to the forward end of the diagonal 
brace on the outboard struts of two Model 747 series airplanes powered 
by General Electric CF6-50 series engines. Both airplanes had 
previously accomplished the strut/wing modification required by AD 95-
13-07, amendment 39-9287 (60 FR 33336, June 28, 1995), which requires 
the accomplishment of Boeing Alert Service Bulletin 747-54A2158.
    One operator reported that the sealant backup plates were not 
reinstalled during the accomplishment of Boeing Alert Service Bulletin 
747-54A2158. In that case, the airplane had accumulated approximately 
371 flight cycles and 1,781 flight hours since the accomplishment of 
the service bulletin. Another operator reported using BMS 5-95 sealant 
to seal the area, instead of using the higher heat-resistant BMS 5-63 
sealant. In that case, the airplane had accumulated approximately 591 
flight cycles and 2,653 flight hours since accomplishment of the 
service bulletin. Further investigation revealed that the use of BMS 5-
95 sealant was specified by Boeing Alert Service Bulletin 747-54A2158, 
whereas BMS 5-63 sealant was specified by Boeing Service Bulletin 747-
54A2117.
    The manufacturer reports that operating temperatures at the 
firewall openings exceed the maximum service temperature of BMS 5-95, 
which causes that sealant to harden and disintegrate at those operating 
temperatures. Heat damage to the diagonal brace, if not corrected, 
could result in cracking or fracture of the diagonal brace, and 
possible loss of the diagonal brace load path and consequent separation 
of the strut and engine from the airplane.

[[Page 31528]]

    The nacelle struts for General Electric CF6-45 and Pratt & Whitney 
JT9D-70 series engines are similar in design to the nacelle struts for 
General Electric CF6-50 series engines. Therefore, the FAA has 
determined that airplanes with any of these engines may be subject to 
the same unsafe condition.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-54A2208, dated March 29, 2001, which describes procedures for a 
detailed visual inspection of the outboard diagonal brace for heat 
damage and cracking; and follow-on repetitive inspections or corrective 
actions, if necessary. The inspection for signs of heat damage includes 
looking for discoloration or changes in primer color, and using the 
primer color at the aft end of the diagonal brace as a reference point. 
Corrective actions include replacing the diagonal brace, installing the 
backup plates, and replacing the existing sealant with heat-resistant 
BMS 5-63 sealant. Accomplishment of certain inspections of the backup 
plate and diagonal brace and corrective actions if necessary, and 
replacement of the sealant with heat-resistant sealant would constitute 
terminating action for the repetitive inspections.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Model 747-100, 747-200, 747-300, and 747SR 
series airplanes powered by General Electric CF6-45/50 and Pratt & 
Whitney JT9D-70 series engines of the same type design, this AD is 
being issued to detect and correct heat damage to the diagonal brace, 
which could cause cracking or fracture of the diagonal brace, and 
possible loss of the diagonal brace load path and consequent separation 
of the strut and engine from the airplane. This AD also provides an 
optional terminating action for the requirements of this AD. This AD 
requires the accomplishment of the actions specified in this AD in 
accordance with Boeing Alert Service Bulletin 747-54A2208, as described 
previously, except as discussed below.

Differences Between the Service Information and This AD

    Operators should note that, although Model 747-100 series airplanes 
are not listed in the effectivity of the previously referenced service 
bulletin, that model airplane is included in the applicability of this 
AD. The nacelle struts of General Electric CF6-45/50 and Pratt & 
Whitney JT9D-70 series engines on Model 747-100 series airplanes are 
similar in design to the nacelle struts on Model 747-200, 747-300, and 
747SR series airplanes. Therefore, Model 747-100 series airplanes may 
be subject to the same unsafe condition revealed on Model 747-200, 747-
300, and 747SR series airplanes.
    Operators also should note that the previously referenced service 
bulletin specifies that the manufacturer may be contacted for 
disposition of certain replacement instructions. However, this AD 
requires the accomplishment of such action per a method approved by the 
FAA, or in accordance with data meeting the type certificate basis of 
the airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the FAA to make such 
findings.

Interim Action

    The FAA is considering further rulemaking action to supersede this 
AD to require removal of the existing sealant and replacement with 
heat-resistant sealant, which would constitute terminating action for 
the repetitive inspections required by this AD action. However, the 
planned compliance time for these actions is sufficiently long so that 
prior notice and time for public comment will be practicable.

Determination of Rule's Effective Date

    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 shall 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.
    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 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 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 rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-118-AD.'' The postcard will be date stamped 
and returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it 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.

[[Page 31529]]

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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

2001-12-05  Boeing: Amendment 39-12260. Docket 2001-NM-118-AD.

    Applicability: Model 747-100, 747-200, 747-300, and 747SR series 
airplanes, certificated in any category, powered by General Electric 
CF6-45/50 series engines, or Pratt & Whitney JT9D-70 series engines.

    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 detect and correct heat damage to the diagonal brace, which 
could cause cracking or fracture of the diagonal brace, and possible 
loss of the diagonal brace load path and consequent separation of 
the strut and engine from the airplane, accomplish the following:

Verification

    (a) Within 90 days after the effective date of this AD, do the 
actions required by paragraph (a)(1) or (a)(2) of this AD, as 
applicable.
    (1) If an operator's maintenance records verify that, during the 
accomplishment of AD 95-13-07, amendment 39-9287, the seal backup 
plates were restored and BMS 5-63 high-temperature sealant was used 
in that restoration, no further action is required by this AD.
    (2) If an operator's maintenance records do not verify that the 
actions specified in paragraph (a)(1) were accomplished, do the 
actions required by paragraph (b) of this AD.

Inspections and Corrective Actions

    (b) Within 90 days after the effective date of this AD, do the 
inspections and applicable corrective actions specified by 
paragraphs (b)(1) and (b)(2) of this AD per the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-54A2208, dated 
March 29, 2001. Thereafter, repeat the inspections at intervals not 
to exceed 6 months, except as provided by paragraph (c) of this AD.

Outboard Strut Diagonal Brace

    (1) Do a detailed visual inspection of the forward 20 inches of 
the outboard strut diagonal brace, including all areas of the 
forward clevis lugs and brace body, for signs of heat damage or 
cracks, per Part 1 of the Accomplishment Instructions of the service 
bulletin.
    (i) If no sign of heat damage or cracking is found, repeat the 
detailed visual inspection at intervals not to exceed 6 months per 
the service bulletin, until accomplishment of paragraph (c) of this 
AD.
    (ii) If any primer discoloration is found, before further 
flight, do a non-destructive test (NDT) inspection of the area to 
determine if the diagonal brace has heat damage per Part 1 of the 
Accomplishment Instructions of the service bulletin.
    (A) If no heat damage is found during the NDT inspection, and no 
cracking is found during the detailed visual inspection, repeat the 
detailed visual inspection specified by paragraph (b)(1) of this AD 
at intervals not to exceed 6 months.
    (B) If any heat damage is found during the NDT inspection, or 
any cracking is found during the detailed visual inspection, before 
further flight, do the action specified in paragraph (c)(2) of this 
AD. Thereafter, repeat the detailed visual inspection specified by 
paragraph (b)(1) of this AD at intervals not to exceed 6 months.

Firewall Openings of the Strut Aft Bulkhead

    (2) Do a detailed visual inspection of the firewall openings of 
the strut aft bulkhead to verify installation of seal backup plates 
and condition of the sealant application per Part 1 of the 
Accomplishment Instructions of the service bulletin.
    (i) If no discrepancy (including damaged or missing seal backup 
plates, or damaged or missing sealant) is found, repeat the detailed 
visual inspection specified by paragraph (b)(1) of this AD at 
intervals not to exceed 6 months.
    (ii) If the seal backup plates are not installed, before further 
flight, install the seal backup plates and apply heat-resistant 
sealant, BMS 5-63, per Part 2 of the Accomplishment Instructions of 
the service bulletin. Accomplishment of this action terminates the 
repetitive inspections required by this AD.
    (iii) If the seal backup plates are installed, but the sealant 
application is damaged or missing, before further flight, remove any 
existing sealant and apply heat-resistant sealant, BMS 5-63, per 
Part 3 of the Accomplishment Instructions of the service bulletin. 
Accomplishment of this action terminates the repetitive inspections 
required by this AD.

    Note 2: Because it is difficult to distinguish between BMS 5-95 
and BMS 5-63 sealants, removal and replacement of the existing 
sealant is required to ensure that the correct heat-resistant 
sealant, BMS 5-63, is used.

Optional Terminating Action

    (c) Accomplishment of the inspections required by paragraphs 
(b)(1) and (b)(2) of this AD and the actions specified by paragraphs 
(c)(1), (c)(2), and (c)(3) of this AD, as applicable, constitutes 
terminating action for the requirements of this AD.
    (1) Before further flight following the inspections required by 
paragraphs (b)(1) and (b)(2) of this AD, if no cracking or heat 
damage is found and the seal backup plates are installed, remove any 
existing sealant and apply heat-resistant sealant, BMS 5-63, per 
Part 3 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 747-54A2208, dated March 29, 2001.
    (2) If any sign of heat damage or cracking is found during the 
inspections required by paragraph (b) of this AD, before further 
flight, do the actions specified by either paragraph (c)(2)(i) or 
(c)(2)(ii) of this AD.
    (i) Replace the diagonal brace per Part 4 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-54A2208, dated 
March 29, 2001; or
    (ii) 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.
    (3) If the seal back-up plates are missing, before further 
flight, do the actions required by paragraph (b)(2)(ii) 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 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

    (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.

Incorporation by Reference

    (f) Except as provided by paragraph (c)(2)(ii) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-54A2208, dated March 29, 2001. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a)

[[Page 31530]]

and 1 CFR part 51. Copies may be obtained from Boeing Commercial 
Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

Effective Date

    (g) This amendment becomes effective on June 27, 2001.

    Issued in Renton, Washington, on June 4, 2001.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-14533 Filed 6-11-01; 8:45 am]
BILLING CODE 4910-13-U