AD Amdt-39-10139

[Federal Register Volume 62, Number 183 (Monday, September 22, 1997)]
[Rules and Regulations]
[Pages 49431-49433]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 97-25042]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-237-AD; Amendment 39-10139; AD 97-20-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

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 series airplanes. This action 
requires repetitive inspections to detect cracks, corrosion, or damage 
of the lower spar fitting body and lug, and corrective actions, if 
necessary. This AD also provides for optional terminating action for 
the repetitive inspection requirements. This amendment is prompted by 
reports that fatigue cracking was found in the lower spar fitting lug 
on the number 3 pylon and in the lower spar fitting body. The actions 
specified in this AD are intended to detect and correct such fatigue 
cracking, which could result in failure of the strut and separation of 
the engine from the airplane.

DATES: Effective October 7, 1997.
    The incorporation by reference of Boeing Service Bulletin 747-54-
2062,

[[Page 49432]]

Revision 8, dated August 21, 1997, as listed in the regulations, is 
approved by the Director of the Federal Register as of October 7, 1997.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2158, dated November 30, 1994, was approved previously by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 
1 CFR part 51 as of July 28, 1995 (60 FR 33336, June 28, 1995). The 
incorporation by reference of Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, was approved previously by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 
1 CFR part 51 as of June 21, 1995 (60 FR 27008, May 22, 1995).
    Comments for inclusion in the rules docket must be received on or 
before November 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-237-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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. Dow, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2771; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On September 21, 1995, the FAA issued AD 95-
20-05, amendment 39-9383 (60 FR 51704, October 3, 1995), applicable to 
certain Boeing Model 747 series airplanes, to require repetitive 
inspections for cracking in the inboard strut-to-diagonal brace attach 
fittings, and repair or replacement, if necessary. That AD also 
provides for an optional terminating modification for the required 
inspections. The requirements of that AD are intended to prevent 
failure of the strut and separation of an engine from the airplane due 
to cracking of the inboard strut-to-diagonal brace attach fittings.
    Since issuance of that AD, the FAA has received reports of fatigue 
cracking in the lower spar fitting lug on the number 3 pylon and in the 
lower spar fitting body on Boeing Model 747 series airplanes. This 
cracking area is beyond the inspection area specified in AD 95-20-05.
    The airplane on which the lower spar fitting lug was cracked had 
accumulated 12,734 total flight cycles with 64,537 total flight hours. 
The lower spar fitting with the cracked lug had accumulated 1,078 
flight cycles from the previous inspection required by AD 95-20-05. The 
lower spar fitting with the cracked body had accumulated less than 
1,000 flight cycles from the previous inspection required by AD 95-20-
05.
    Fatigue cracking in the lower spar fitting lug or the lower spar 
fitting body, if not detected and corrected in a timely manner, could 
result in failure of the strut and separation of the engine from the 
airplane.

Explanation of Relevant Service Information

    Subsequent to the finding of this new cracking, the manufacturer 
issued, and the FAA reviewed and approved Boeing Service Bulletin 747-
54-2062, Revision 8, dated August 21, 1997. The service bulletin 
describes procedures for repetitive detailed visual and ultrasonic 
inspections to detect cracks, corrosion, or damage of the lower spar 
fitting body and lug, as applicable, and replacement, if necessary. The 
service bulletin also describes procedures for replacement of the lower 
spar fitting with a new steel lower spar fitting, which eliminates the 
need 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 Boeing Model 747 series airplanes of the same 
type design, this AD is being issued to detect and correct fatigue 
cracking in the lower spar fitting lug or the lower spar fitting body, 
which could result in failure of the strut and separation of the engine 
from the airplane. This AD requires repetitive detailed visual and 
ultrasonic inspections to detect cracks, corrosion, or damage of the 
lower spar fitting body and lug, as applicable, and replacement, if 
necessary. This AD also provides for an optional replacement of the 
lower spar fitting with a new steel lower spar fitting, which 
constitutes terminating action for the repetitive inspection 
requirements. The actions are required to be accomplished in accordance 
with the service bulletin described previously. In lieu of 
accomplishing the subject replacement or repetitive inspections, this 
AD provides for an optional terminating modification of the nacelle 
strut and wing structure. (This modification is part of the ``Boeing 
Model 747 Strut and Wing Structural Modification Program,'' described 
in Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994, 
and Boeing Alert Service Bulletin 747-54A2158, dated November 30, 
1994.)

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.
    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 97-NM-237-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or

[[Page 49433]]

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 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.

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:

97-20-01  Boeing: Amendment 39-10139. Docket 97-NM-237-AD.

    Applicability: Model 747 series airplanes, having line numbers 1 
through 500 inclusive, equipped with Pratt & Whitney Model JT9D-3, -
7, or -7Q engines, or having line numbers 202, 204, 232, or 257, 
equipped with General Electric Model CF6 series engines; 
certificated in any category; and on which the strut/wing 
modification has not been accomplished in accordance with either of 
the following Boeing service bulletins:
    <bullet> Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994, or
    <bullet> Boeing Alert Service Bulletin 747-54A2158, dated 
November 30, 1994.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise 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) 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 fatigue cracking in the lower spar fitting 
lug or the lower spar fitting body, which could result in failure of 
the strut and separation of the engine from the airplane, accomplish 
the following:
    (a) Within 90 days after the effective date of this AD, perform 
a detailed visual inspection and an ultrasonic inspection to detect 
cracks, corrosion, or damage of the lower spar fitting body and lug, 
as applicable, in accordance with Figures 9 and 10 of Boeing Service 
Bulletin 747-54-2062, Revision 8, dated August 21, 1997.

    Note 2: This AD does not require an inspection of the inboard 
strut-to-diagonal brace attach fitting as described in Figure 1 of 
Boeing Service Bulletin 747-54-2062, Revision 8, dated August 21, 
1997. However, this inspection is required to be accomplished as 
part of AD 95-20-05, amendment 39-9383 (60 FR 51705, October 10, 
1995).

    (1) If no crack, corrosion, or damage is detected, repeat the 
detailed visual and ultrasonic inspections thereafter at intervals 
not to exceed 400 landings.
    (2) If any crack, corrosion, or damage is detected, prior to 
further flight, accomplish either paragraph (a)(2)(i) or (a)(2)(ii) 
of this AD.
    (i) Replace the lower spar fitting with a new steel lower spar 
fitting, in accordance with Part II of the Accomplishment 
Instructions of the service bulletin. Or
    (ii) Modify the nacelle strut and wing structure in accordance 
with Boeing Alert Service Bulletin 747-54A2158, dated November 30, 
1994, or Boeing Alert Service Bulletin 747-54A2159, dated November 
3, 1994.
    (b) Replacement of the lower spar fitting with a new steel lower 
spar fitting, in accordance with Part II of the Accomplishment 
Instructions of Boeing Service Bulletin 747-54-2062, Revision 8, 
dated August 21, 1997; or modification of the nacelle strut and wing 
structure in accordance with Boeing Alert Service Bulletin 747-
54A2158, dated November 30, 1994, or Boeing Alert Service Bulletin 
747-54A2159, dated November 3, 1994; constitutes terminating action 
for the repetitive inspection requirements of this AD.
    (c) 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 Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. 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.

    (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.
    (e) The inspections and replacement shall be done in accordance 
with Boeing Service Bulletin 747-54-2062, Revision 8, dated August 
21, 1997. The modification, if accomplished, shall be done in 
accordance with Boeing Alert Service Bulletin 747-54A2158, dated 
November 30, 1994, or Boeing Alert Service Bulletin 747-54A2159, 
dated November 3, 1994.
    (1) The incorporation by reference of Boeing Service Bulletin 
747-54-2062, Revision 8, dated August 21, 1997, is approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 747-54A2158, dated November 30, 1994, was approved 
previously by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR Part 51 as of July 28, 1995 (60 FR 
33336, June 28, 1995).
    (3) The incorporation by reference of Boeing Alert Service 
Bulletin 747-54A2159, dated November 3, 1994, was approved 
previously by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR Part 51 as of June 21, 1995 (60 FR 
27008, May 22, 1995).
    (4) 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.
    (f) This amendment becomes effective on October 7, 1997.

    Issued in Renton, Washington, on September 15, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-25042 Filed 9-19-97; 8:45 am]
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