[Federal Register Volume 62, Number 2 (Friday, January 3, 1997)]
[Rules and Regulations]
[Pages 302-304]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-114]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-280-AD; Amendment 39-9868; AD 96-26-52]
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 document publishes in the Federal Register an amendment 
adopting Airworthiness Directive (AD) T96-26-52 that was sent 
previously to all known U.S. owners and operators of Boeing Model 747 
series airplanes by individual telegrams. This AD requires repetitive 
inspections of the access doors to the midspar/spring beam fuse pins on 
all engine pylons to detect cracks on the external surface; repetitive 
inspections of each midspar/spring beam fuse pin to detect if it 
protrudes beyond its mating nut by a specified distance; and repair of 
any discrepancy found. This action is prompted by a report indicating 
that a fuse pin had migrated on an inboard spring beam fitting on the 
Number 1 engine pylon of a Boeing Model 747-400 airplane. The actions 
specified by this AD are intended to prevent migration of this fuse 
pin, which, if not detected and corrected in a timely manner, could 
result in failure of the engine pylon and consequent separation of the 
engine from the wing.

DATES: Effective January 8, 1997, to all persons except those persons 
to whom it was made immediately effective by telegraphic AD T96-26-52, 
issued December 20, 1996, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before March 4, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-280-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    Service information pertaining to this rulemaking action 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 L. Dow, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056, telephone (206) 227-2771; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: On December 20, 1996, the FAA issued 
telegraphic AD T96-26-52, which is applicable to certain Boeing Model 
747 series airplanes.
    That action was prompted by a report indicating that a fuse pin had 
migrated \5/8\ inch out of an inboard spring beam fitting on the Number 
1 engine pylon of a Boeing Model 747-400 series airplane. In addition, 
the mating nut to this pin had backed off approximately \3/10\ inch 
from full engagement with the pin. The discrepant fuse pin was detected 
after maintenance personnel observed that the access door (part number 
65B94112-43) to this fuse pin protruded outward from its adjacent pylon 
structure.
    At the time this discrepancy was found, the airplane had 
accumulated 12,446 total hours time-in-service, and accomplished 1,439 
total landings. Prior to delivery of this airplane in June 1994, the 
manufacturer had installed fuse pins in the spring beam fitting that 
are made of 15-5 corrosion resistant steel (``third generation pins''). 
These pins replaced existing pins made of 4330 or 4340 steel.
    Migration of the fuse pin, if not detected and corrected in a 
timely manner, could result in failure of the engine pylon and 
consequent separation of the engine from the wing.

Other Relevant Rulemaking

    The FAA previously had issued AD 95-13-05 [amendment 39-9285 (60 FR 
33333, dated June 28, 1995; as corrected at 60 FR 35452, July 7, 
1995)], which applies to certain Boeing Model 747 series airplanes 
equipped with Rolls Royce Model RB211 series engines. The FAA also had 
issued AD 95-13-06 [amendment 39-9286 (60 FR 33338, June 28, 1995; as 
corrected at 60 FR 37500, July 20, 1995)], which applies to certain 
Model 747 series airplanes equipped with General Electric Model CF6-
80C2 series engines or Pratt & Whitney Model PW4000 series engines. 
These AD's, which are almost identical, require modification of the 
nacelle strut and wing structure of the applicable airplanes. Among the 
actions required by both AD's is the installation of a mechanical 
secondary retention to prevent the fuse pins for the midspar/spring 
beam fittings from migrating.
    At the time the discrepancy described above was discovered, the 
nacelle strut and wing modification had not yet been accomplished on 
the incident airplane;

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consequently, the secondary retention device had not yet been installed 
either. (The secondary retention device has been installed during 
production of airplanes beginning at line number 1047.)

Explanation of Requirements of the Rule

    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design, the FAA issued Telegraphic 
AD T96-26-52 to prevent migration of this fuse pin, subsequent failure 
of the engine pylon, and consequent separation of the engine from the 
wing. The AD requires repetitive detailed visual inspections of the 
access doors to the midspar/spring beam fuse pins on all engine pylons 
to detect cracks on the external surface, and repair, if necessary. In 
addition, the AD requires repetitive detailed visual inspections of 
each midspar/spring beam fuse pin to detect if it protrudes beyond its 
mating nut by a specified distance, and repair, if necessary. These 
inspections are to be repeated until the terminating modifications 
currently required by AD 95-13-05 or AD 95-13-06, as applicable, are 
accomplished.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual telegrams 
issued on December 20, 1996, to all known U.S. owners and operators of 
Boeing Model 747 series airplanes. These conditions still exist, and 
the AD is hereby published in the Federal Register as an amendment to 
section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to 
make it effective to all persons.

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 96-NM-280-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 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, 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:

96-26-52  Boeing: Amendment 39-9868. Docket 96-NM-280-AD.

    Applicability: Model 747 series airplanes having line numbers 1 
through 1046, inclusive; certificated in any category; that meet all 
of the following criteria:
     equipped with Pratt & Whitney Model PW4000 series 
engines, or General Electric Model CF6-80C2 series engines, or Rolls 
Royce Model RB211 series engines;
     on which fuse pins having part numbers 310U2301-101, -
116, -117, or -120 (``third generation'' fuse pins) are installed at 
the midspar/spring beam fittings of the engine pylon; and
     on which the modification of the nacelle strut and wing 
structure in accordance with Boeing Alert Service Bulletin 747-
54A2156 or Boeing Alert Service Bulletin 747-54A2157, as applicable, 
has not been accomplished.

    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 prevent failure of the engine pylon and consequent separation 
of the engine from the wing, due to migration of the fuse pins 
installed at the midspar/spring beam fittings of the pylon, 
accomplish the following:
    (a) Within 15 days after the receipt of this AD, accomplish the 
requirements of paragraphs (a)(1) and (a)(2) of this AD.
    (1) Perform a detailed visual inspection of the access doors to 
each midspar/spring beam fuse pin on each engine pylon to detect 
cracks on the external surface of the doors.
    (i) If no cracking is detected during the inspection, repeat 
that inspection at intervals not to exceed 150 landings or 1,000 
hours time-in-service, whichever occurs first.
    (ii) If any cracking is detected during the inspection, prior to 
further flight, repair in accordance with a method approved by the 
Manager, Seattle Aircraft Certification Office

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(ACO), FAA, Transport Airplane Directorate. Thereafter, repeat the 
inspection at intervals not to exceed 150 landings or 1,000 hours 
time-in-service, whichever occurs first.
    (2) Gain access through the aft fairing doors of each engine 
pylon to each midspar/spring beam fuse pin and its mating, self-
locking nut, and perform a detailed visual inspection of each fuse 
pin to verify that at least one thread of the fuse pin protrudes 
beyond its mating, self-locking nut.
    (i) If no discrepancy is detected during the inspection, repeat 
that inspection at intervals not to exceed 150 landings or 1,000 
hours time-in-service, whichever occurs first.
    (ii) If the inspection reveals that at least one thread does not 
protrude beyond its mating, self-locking nut, prior to further 
flight, repair in accordance with a method approved by the Manager, 
Seattle ACO, FAA, Transport Airplane Directorate. Thereafter, repeat 
the inspection at intervals not to exceed 150 landings or 1,000 
hours time-in-service, whichever occurs first.
    (b) Accomplishment of the modification of the nacelle strut and 
wing structure in accordance with Boeing Alert Service Bulletin 747-
54A2156, Revision 2, dated December 21, 1995, or earlier revisions 
(for airplanes equipped with General Electric Model CF6-80C2 series 
engines, or Pratt & Whitney PW4000 series engines); or Boeing Alert 
Service Bulletin 747-54A2157, Revision 2, dated November 14, 1996, 
or earlier revisions (for airplanes with Rolls Royce Model RB211 
series engines); as applicable; constitutes terminating action for 
the repetitive detailed visual inspections required by paragraphs 
(a)(1) and (a)(2) 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 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 2: 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) This amendment becomes effective on January 8, 1997, to all 
persons except those persons to whom it was made immediately 
effective by telegraphic AD T96-26-52, issued on December 20, 1996, 
which contained the requirements of this amendment.

    Issued in Renton, Washington, on December 23, 1996.
S. R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-114 Filed 1-2-97; 8:45 am]
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