[Federal Register Volume 62, Number 128 (Thursday, July 3, 1997)]
[Rules and Regulations]
[Pages 35953-35956]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-17284]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-94-AD; Amendment 39-10064; AD 97-14-06]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes, 
Excluding Airplanes Equipped With Pratt & Whitney PW4000 and General 
Electric CF6-80C2 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing 747 series airplanes, that currently 
requires replacement of certain fuse pins on the upper link of the 
inboard and outboard struts. That AD also requires inspections to 
detect corrosion or cracks of certain fuse pins, and replacement, if 
necessary. This amendment reduces the compliance times of actions 
associated with certain fuse pins and provides for optional terminating 
action for the requirements of this AD. This amendment is prompted by a 
report of fracturing of a bulkhead style fuse pin located in the 
inboard strut at the forward end of the upper link. The actions 
specified in this AD are intended to prevent failure of the strut and 
separation of an engine from the airplane due to fracturing of the fuse 
pins.

DATES: Effective July 18, 1997.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2166, dated May 1, 1997, as listed in the regulations, is 
approved by the Director of the Federal Register as of July 18, 1997.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2166, dated April 28, 1994, as listed in the regulations, was 
approved previously by the Director of the Federal Register as of April 
13, 1995 (60 FR 13618, March 14, 1995).
    Comments for inclusion in the Rules Docket must be received on or 
before September 2, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-94-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
Boeing

[[Page 35954]]

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, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington; telephone, (425) 227-2771; 
fax, (425) 227-1181.

SUPPLEMENTARY INFORMATION: On March 3, 1995, the FAA issued AD 95-06-
02, amendment 39-9172 (60 FR 13618, March 14, 1995), to require 
replacement of certain fuse pins on the upper link of the inboard and 
outboard struts. That AD also currently requires inspections to detect 
corrosion or cracks of certain fuse pins, and replacement, if 
necessary. [A correction of the rule was published in the Federal 
Register on April 19, 1995 (60 FR 19492).] That action was prompted by 
reports of cracked or corroded fuse pins on the upper link of the 
inboard and outboard struts, which could result in fracturing of the 
pins.

Actions Since Issuance of Previous Rule

    Since the issuance of AD 95-06-02, the FAA received a report 
indicating that a fracture of a bulkhead style fuse pin located in the 
inboard strut at the forward end of the upper link had occurred on a 
Boeing Model 747 series airplane. The bulkhead style fuse pin had 
accumulated 7,750 flight cycles and 42,027 flight hours. Metallurgical 
analysis of this pin indicated that the cause of the cracking was 
fatigue. Fracturing of the fuse pins, if not corrected, could result in 
failure of the strut and separation of an engine from the airplane.

Explanation of Relevant Service Information

    Since the issuance of the previous rule, the FAA has reviewed and 
approved Boeing Alert Service Bulletin 747-54A2166, Revision 1, dated 
May 1, 1997, which reduces the recommended times for actions associated 
with certain fuse pins. The alert service bulletin references Boeing 
Alert Service Bulletins 747-54A2157, 747-54A2158, and 747-54A2159, 
which describe procedures for modification of the strut/wing. The alert 
service bulletin also references Boeing Service Bulletin 747-54-2155, 
which describes procedures for installation of 15-5 corrosion resistant 
steel (third generation) fuse pins in the forward and aft positions of 
the upper link on the inboard or outboard strut. Accomplishment of 
either the strut/wing modification or installation of 15-5 fuse pins 
eliminates the need for additional inspections or replacement of fuse 
pins.

Explanation of Requirements of Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 95-06-02 to continue to require replacement of certain 
fuse pins on the upper link of the inboard and outboard struts. This AD 
also continues to require inspections to detect corrosion or cracks of 
certain fuse pins, and replacement, if necessary. This amendment 
reduces the compliance times of actions associated with certain 
bulkhead fuse pins. This amendment also provides for optional 
terminating action for the requirements of this AD.
    This is considered to be interim action. The FAA may consider 
further rulemaking action to require the accomplishment of the optional 
terminating action [installation of 15-5 corrosion resistant steel 
(third generation) fuse pins] currently specified in this AD. However, 
the proposed compliance time for accomplishment of that action 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.
    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-94-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, 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

[[Page 35955]]

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 39-9172 (60 FR 
13618, March 14, 1995), and by adding a new airworthiness directive 
(AD), amendment 39-10064, to read as follows:

97-14-06 Boeing: Amendment 39-10064. Docket 97-NM-94-AD. Supersedes 
AD 95-06-02, Amendment 39-9172.

    Applicability: Model 747 and 747-400 series airplanes, line 
numbers 1 through 967 inclusive, and 969 through 992 inclusive; 
certificated in any category; excluding airplanes equipped with 
Pratt & Whitney PW4000 or General Electric CF6-80C2 series engines; 
and excluding airplanes on which the strut/wing modification has 
been accomplished in accordance with AD 95-13-05, amendment 39-9285, 
AD 95-13-07, amendment 39-9287; or AD 95-10-16, amendment 39-9233.

    Note 1: This AD does not require that the actions be 
accomplished on those airplanes having pylons on which 15-5 
corrosion resistant steel (third generation) fuse pins are installed 
through the upper link of the inboard and outboard struts.
    Note 2: 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 otherwise 
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 (h) 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 strut and loss of an engine due to 
corrosion or cracking of the fuse pins, accomplish the following:
    (a) For airplanes having bottle bore style fuse pins in the 
forward position on the upper link: Replace any bottle bore style 
fuse pin with a new bulkhead style fuse pin in the forward position, 
or with 15-5 corrosion resistant steel (third generation) fuse pins 
in the forward position, in accordance with Boeing Alert Service 
Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, dated May 
1, 1997, at the later of the times specified in paragraphs (a)(1) 
and (a)(2) of this AD.
    (1) Prior to the accumulation of 5,000 total landings on the 
fuse pin, or within 5 years since installation of the pin, whichever 
occurs first. Or
    (2) Within 6 months after April 13, 1995 (the effective date of 
AD 95-06-02, amendment 39-9172).

    Note 3: Third generation fuse pins are installed in pairs (in 
the forward and aft positions). Therefore, replacement of an 
individual upper link fuse pin in the forward position with a third 
generation pin also would necessitate replacement of the pin in the 
aft position.
    Note 4: The alert service bulletin references Boeing Service 
Bulletin 747-54-2155, dated September 23, 1993, as an additional 
source of service information for replacement of the fuse pins with 
15-5 corrosion resistant steel (third generation) fuse pins. 
Installation of these third generation fuse pins is preferred over 
installation of bulkhead style fuse pins.

    (b) For airplanes having bulkhead style fuse pins in the forward 
position on the upper link: Perform a detailed visual inspection to 
detect corrosion of the pins, and a magnetic particle inspection to 
detect cracks, in accordance with Boeing Alert Service Bulletin 747-
54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997, at 
the earlier of the times specified in paragraphs (b)(1) and (b)(2) 
of this AD.
    (1) Perform the inspections at the later of the times specified 
in paragraphs (b)(1)(i) and (b)(1)(ii) of this AD.
    (i) Prior to the accumulation of 8,000 total landings on the 
fuse pin, or within 8 years since installation of the pin, whichever 
occurs first. Or
    (ii) Within 12 months after April 13, 1995.
    (2) Perform the inspections at the later of the times specified 
in paragraphs (b)(2)(i) and (b)(2)(ii) of this AD.
    (i) Prior to the accumulation of 5,000 total landings on the 
fuse pin, or within 5 years since installation of the pin, whichever 
occurs first. Or
    (ii) Within 90 days after the effective date of this AD.
    (c) For the inboard and outboard struts on airplanes other than 
those identified in paragraph (d) of this AD: If no corrosion or 
crack is found during the inspection required by paragraph (b) of 
this AD, repeat the inspection thereafter, in accordance with Boeing 
Alert Service Bulletin 747-54A2166, dated April 28, 1994, or 
Revision 1, dated May 1, 1997, at the time specified in paragraph 
(c)(1) or (c)(2) of this AD, as applicable.
    (1) For airplanes on which the initial inspection required by 
paragraph (a) or (b) of AD 95-06-02 has been accomplished prior to 
the effective date of this AD: Repeat the inspection within 1,000 
landings since the last inspection in accordance with AD 95-06-02, 
or within 500 landings after the effective date of this AD, 
whichever occurs first, and thereafter at intervals not to exceed 
500 landings.
    (2) For airplanes other than those identified in paragraph 
(c)(1) of this AD: Repeat the inspection thereafter at intervals not 
to exceed 500 landings.
    (d) For the outboard struts on airplanes equipped with Rolls-
Royce RB211-524G or -524H series engines: If no corrosion or crack 
is found during the inspection required by paragraph (b) of this AD, 
repeat the inspection thereafter in accordance with Boeing Alert 
Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, 
dated May 1, 1997, at the time specified in paragraph (d)(1) or 
(d)(2) of this AD, as applicable.
    (1) For airplanes on which the initial inspection required by 
paragraph (a) or (b) of AD 95-06-02 has been accomplished prior to 
the effective date of this AD: Repeat the inspection within 2,000 
landings since the last inspection in accordance with AD 95-06-02, 
or within 1,000 landings after the effective date of this AD, 
whichever occurs first, and thereafter at intervals not to exceed 
500 landings.
    (2) For airplanes other than those identified in paragraph 
(d)(1) of this AD: Repeat the inspection thereafter at intervals not 
to exceed 500 landings.

    Note 5: The outboard struts of airplanes equipped with Rolls-
Royce RB211-524G or -524H series engines are equipped with thick 
wall ``4330 steel'' bulkhead style fuse pins in the forward position 
of the upper link. Crack propagation to critical length in these 
thick wall pins is slower than for pins installed on the struts of 
airplanes equipped with engines other than the Rolls-Royce RB211-
524G or -524H series.

    (e) If any corrosion or crack is found during any inspection 
required by this AD, prior to further flight, replace the corroded 
or cracked pin with either a new bulkhead style fuse pin in the 
forward position of the upper link, or with 15-5 corrosion resistant 
steel (third generation) fuse pins in the forward and aft positions 
of the upper link; in accordance with Boeing Alert Service Bulletin 
747-54A2166, dated April 28, 1994, or Revision 1, dated May 1, 1997. 
Accomplish inspections, if applicable, as specified in paragraph 
(e)(1) or (e)(2).
    (1) If the corroded or cracked fuse pin is replaced with a new 
bulkhead style fuse pin, prior to the accumulation of 5,000 total 
landings on the new pin, or within 5 years since installation of the 
new pin, whichever occurs first, perform a detailed visual 
inspection to detect corrosion of the new pin, and a magnetic 
particle inspection to detect cracks of the new pin, in accordance 
with the alert service bulletin. Repeat these inspections thereafter 
at the interval specified in paragraph (e)(1)(i) or (e)(1)(ii) of 
this AD, as applicable.
    (i) For the inboard and outboard struts on airplanes other than 
those identified in paragraph (e)(1)(ii) of this AD: Repeat the 
inspections at intervals not to exceed 500 landings.
    (ii) For the outboard struts on airplanes equipped with Rolls-
Royce RB211-524G or -524H series engines: Repeat the inspections at 
intervals not to exceed 1,000 landings.
    (2) If the corroded or cracked fuse pin is replaced with a 15-5 
corrosion resistant steel (third generation) fuse pin, no further 
action is required by this AD.
    (f) Accomplishment of the strut/wing modification in accordance 
with Boeing Alert Service Bulletin 747-54A2166, Revision 1, dated 
May 1, 1997, constitutes terminating action for the requirements of 
this AD.


[[Page 35956]]


    Note 6: Boeing Alert Service Bulletin 747-54A2166, Revision 1, 
references Boeing Alert Service Bulletins 747-54A2157, 747-54A2158, 
and 747-54A2159 as additional sources of service information for 
accomplishment of the strut/wing modification.

    (g) Installation of 15-5 corrosion resistant steel (third 
generation) fuse pins in the forward and aft positions of the upper 
link on the inboard or outboard strut in accordance with Boeing 
Alert Service Bulletin 747-54A2166, Revision 1, dated May 1, 1997, 
constitutes terminating action for the requirements of this AD.
    (h) 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 7: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (i) 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.
    (j) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-54A2166, dated April 28, 1994, or Revision 1, 
dated May 1, 1997. The incorporation by reference of Boeing Alert 
Service Bulletin 747-54A2166, dated April 28, 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 April 13, 1995 (60 FR 
13618, March 14, 1995). The incorporation by reference of Boeing 
Alert Service Bulletin 747-54A2166, Revision 1, dated May 1, 1997, 
was approved by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) 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.
    (k) This amendment becomes effective on July 18, 1997.

    Issued in Renton, Washington, on June 26, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-17284 Filed 7-2-97; 8:45 am]
BILLING CODE 4910-13-U