[Federal Register Volume 62, Number 110 (Monday, June 9, 1997)]
[Rules and Regulations]
[Pages 31331-31336]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-14769]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-70-AD; Amendment 39-10045; AD 97-12-03]
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 supersedes two existing airworthiness 
directives (AD) that are applicable to certain Boeing Model 747 series 
airplanes. One of those AD's currently requires inspections for 
cracking, corrosion, and fracturing of the lower horizontal clevis of 
the strut midspar fittings, and replacement of discrepant parts with 
new or serviceable parts, or repair, if necessary. That AD also 
requires inspection for removal of broken sealant of the clevis and the 
fasteners, and various follow-on actions. It also provides for optional 
terminating actions for the inspections. The other AD currently 
requires inspection for cracking of certain fastener holes of the upper 
and lower horizontal clevis legs. This amendment continues to require 
inspections to detect cracking, corrosion, and fracturing of the lower 
horizontal clevis; and adds corresponding inspections of the upper 
horizontal clevis, and replacement of discrepant parts with new parts, 
or rework, if necessary. This amendment also removes certain optional 
terminating actions. This amendment is prompted by reports of cracking 
of the lower and upper leg of the horizontal clevis of the midspar 
fitting. The actions specified in this AD are intended to detect and 
correct cracking and fracturing of the clevis, which could result in 
drooping of the strut at the strut-to-wing interface, and consequent 
separation of the engine and strut from the airplane.

DATES: Effective June 24, 1997.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2179, Revision 1, dated November 27, 1996, as listed in the 
regulations, is approved by the Director of the Federal Register as of 
June 24, 1997.
    The incorporation by reference of the following publications listed 
in the regulations was approved by the Director of the Federal Register 
as of the specified dates:

------------------------------------------------------------------------
                                              Approval date and Federal 
   Referenced service bulletin and date           Register citation     
------------------------------------------------------------------------
747-54A2157, January 12, 1995.............  July 28, 1995 (60 FR 33333, 
                                             June 28, 1995).            
747-54A2158, November 30, 1994............  July 28, 1995 (60 FR 33336, 
                                             July 28, 1995).            
747-54A2159, November 3, 1994.............  June 21, 1995 (60 FR 27008, 
                                             May 22, 1995).             
------------------------------------------------------------------------

    The incorporation by reference of certain other publications listed 
in the regulations also was approved previously by the Director of the 
Federal Register as of January 22, 1997 (60 FR 66201, December 12, 
1996).
    Comments for inclusion in the Rules Docket must be received on or 
before August 8, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 97-NM-70-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 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 January 13, 1988, the FAA issued AD 87-
04-13 R1, amendment 39-5836 (53 FR 2005, January 26, 1988), applicable 
to certain Boeing Model 747 series airplanes. That AD revised an 
existing AD to require inspection for cracking, and repair or 
replacement, as necessary, of the horizontal clevis of the pylon 
midspar attach fitting. That action was prompted by reports of cracking 
and corrosion in the fastener holes of the

[[Page 31332]]

midspar attach fitting of the engine pylon. The actions required by 
that AD are intended to detect and correct such cracking/corrosion of 
the attach fitting, which could cause possible separation of the pylon 
and engine from the wing.
    In addition, on November 25, 1996, the FAA issued AD 96-25-01, 
amendment 39-9842 (61 FR 66201, December 17, 1996), applicable to 
certain Boeing Model 747 series airplanes, to require inspections to 
detect broken sealant common to the lower horizontal clevis of the 
inboard and outboard strut midspar fittings and of the fasteners, and 
various follow-on actions. That action also requires inspections to 
detect cracking, corrosion, and fracturing of the lower horizontal 
clevis, and replacement of discrepant parts with new or serviceable 
parts, or repair, if necessary. That action also provides for optional 
terminating actions for the repetitive inspections. That action was 
prompted by reports of fatigue cracking, stress corrosion cracking, and 
fracturing of the horizontal clevis of the inboard midspar fitting of 
the number three strut. The actions required by that AD are intended to 
detect and correct such cracking and fracturing, which could result in 
drooping of the strut at the strut-to-wing interface, and consequent 
separation of the engine and strut from the airplane.

Other Relevant Rulemaking

    The FAA has previously issued several other AD's that address 
cracking in the midspar fitting clevis on Boeing Model 747 series 
airplanes:
    1. AD 90-06-06, amendment 39-6490 (55 FR 8374, March 7, 1990): 
Among various other actions, this AD requires structural modification, 
among various other actions, in accordance with Boeing Document No. D6-
35999, dated March 31, 1989. The FAA has approved an alternative method 
of compliance that extends the compliance time threshold to a maximum 
of three years after the airplane reaches 20,000 total flight cycles, 
or until the mandated strut/wing modification is accomplished, 
whichever occurs first. Additionally, ultrasonic inspections to detect 
cracking of the fastener holes are required at intervals not to exceed 
1,000 flight cycles in accordance with Boeing Service Bulletin 747-54-
2118, dated July 26, 1986. If cracking or corrosion is detected during 
those inspections, rework or replacement of the midspar fitting with a 
new or serviceable part is required, in accordance with that service 
bulletin.
    The FAA has approved Boeing Alert Service Bulletin 747-54A2179, 
Revision 1, dated November 27, 1996, as an alternative method of 
compliance for the requirements specified in AD 90-06-06, which 
references Boeing Service Bulletin 747-54-2118 as the appropriate 
source of service information.
    2. AD 95-10-16, amendment 39-9233 (60 FR 27008, May 5, 1995): For 
airplanes equipped with Pratt & Whitney Model JT9D engines (excluding 
Model JT9D-70 engines), that AD requires modification of the nacelle 
strut and wing structure, and inspections of the adjacent structure 
that has not been replaced by the modification, in accordance with 
Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994. As a 
condition to extend the compliance time from 32 to 56 months, AD 95-10-
16 also requires repetitive ultrasonic inspections to detect cracking 
of the aft-most two fastener holes in both strut midspar fittings on 
the inboard and outboard nacelle struts, or modification of the aft-
most two fastener holes as described in Boeing Service Bulletin 747-54-
2118.
    The FAA has approved the inspections of the upper and lower 
horizontal legs of the strut midspar fittings and compliance times for 
those inspections specified in Boeing Alert Service Bulletin 747-
54A2179, Revision 1, dated November 29, 1996, as an alternative to 
those actions specified in paragraphs (a)(2)(ii)(a) and (a)(2)(iv)(a) 
of AD 95-10-16.
    Since the issuance of that AD, Boeing Alert Service Bulletin 747-
54A2159, Revision 1, dated June 1, 1995, and Revision 2, dated March 
14, 1996, have been approved as alternative methods of compliance with 
that AD.
    3. AD 95-13-05, amendment 39-9285 (60 FR 33333, June 28, 1995): For 
airplanes equipped with Rolls Royce Model RB211 series engines, that AD 
requires modification of the strut/wing in accordance with Boeing Alert 
Service Bulletin 747-54A2157, dated January 12, 1995.
    Since the issuance of that AD, Boeing Alert Service Bulletin 747-
54A2157, Revision 1, dated August 3, 1995, and Revision 2, dated 
November 14, 1996, have been approved as alternative methods of 
compliance with the AD.
    4. AD 95-13-07, amendment 39-9287 (60 FR 33336, July 28, 1995): For 
airplanes equipped with General Electric Model CF6-45 or -50 series 
engines, that AD requires modification of the strut/wing in accordance 
with Boeing Alert Service Bulletin 747-54A2158, dated November 30, 
1994.
    Since issuance of that AD, Boeing Alert Service Bulletin 747-
54A2158, Revision 1, dated August 17, 1995, and Revision 2, dated 
August 15, 1996, have been approved as alternative methods of 
compliance with that AD.

Actions Since Issuance of AD 87-04-13 R1 and AD 96-25-01

    Since the issuance of AD 96-25-01, the FAA has received reports 
indicating that cracking was found of the lower and upper leg of the 
horizontal clevis of the midspar fitting on Boeing Model 747 series 
airplanes. The cracking was detected during inspections that were 
conducted in accordance with AD 96-25-01.
    One operator reported that a midspar fitting at the number three 
pylon was cracked at the fourth row of fasteners from the aft end on 
the upper leg of the horizontal clevis of the midspar fitting. This 
operator also reported a crack on the lower leg of the midspar fitting 
at the number two pylon at the second row from the aft end. 
Metallurgical analysis accomplished on the midspar fitting at the 
number three pylon indicates that the cause of the cracking was stress 
corrosion.
    The FAA also received another report indicating that cracking was 
detected on the upper leg of the horizontal clevis of the midspar 
fitting at the second row of fasteners from the aft end at the number 
three pylon. In addition, this report indicated that cracking was also 
detected on that same airplane at the number 3 pylon at the second row 
from the aft end of the lower leg. The report also indicated that 
terminating action specified Boeing Service Bulletin 747-54-2118, dated 
July 25, 1986, had been accomplished on the affected airplane; this 
service bulletin was referenced in AD 96-25-01 as the appropriate 
source of service information.
    Cracking or fracturing of the lower or upper horizontal clevis of 
the inboard and outboard strut midspar fittings, if not detected and 
corrected in a timely manner, could result in drooping of the strut at 
the strut-to-wing interface, and consequent separation of the engine 
and strut from the airplane.

Explanation of New Relevant Service Information

    Since the issuance of AD 87-04-13 R1 and AD 96-25-01, the FAA has 
reviewed and approved Boeing Alert Service Bulletin 747-54A2179, 
Revision 1, dated November 27, 1996. This alert service bulletin 
describes procedures for the following:
    1. Removing sealant common to the lower and upper horizontal legs 
of the clevis of the outboard (for certain airplanes) and the inboard 
(for all airplanes) midspar fittings, and cleaning the midspar 
fittings.

[[Page 31333]]

    2. Performing detailed visual borescope inspections or alternative 
ultrasonic/detailed visual inspections to detect cracking, corrosion, 
and/or fracturing of the lower horizontal legs of the clevis of the 
strut midspar fittings, and repair, if necessary.
    3. Performing ultrasonic and detailed visual inspections to detect 
cracking, corrosion, and/or fracturing of the upper horizontal leg of 
the strut midspar fittings, and repair, if necessary.
    4. Reworking only the discrepant areas or hole.
    5. Reworking all fastener holes, or replacing the midspar fitting 
with new fittings, as applicable, if any discrepancy is detected; this 
eliminates the need for repetitive inspections.
    Additionally, for all airplanes, the service bulletin references 
replacement of the midspar fittings, which involves modification of the 
strut/wing in accordance with the following Boeing service bulletins, 
as applicable. Accomplishment of this modification eliminates the need 
for repetitive inspections.
    1. Boeing Alert Service Bulletin 747-54A2157, dated January 12, 
1995; Revision 1, dated August 3, 1995; or Revision 2, dated November 
14, 1996 (for airplanes equipped with Rolls Royce RB211 engines);
    2. Boeing Alert Service Bulletin 747-54-A2158, dated November 30, 
1994; Revision 1, dated August 17, 1995; or Revision 2, dated August 
15, 1996 (for airplanes equipped with General Electric CFC-45/-50 or 
Pratt & Whitney JT9D-70 engines); and
    3. Boeing Service Bulletin 747-54A2159, dated November 3, 1994; 
Revision 1, dated June 1, 1995; or Revision 2, dated March 14, 1996 
(for airplanes equipped with Pratt & Whitney engines).

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 87-04-13 R1 and AD 96-25-01, as follows:
    First, this AD requires removal of certain sealant common to the 
lower and upper horizontal legs of the outboard (for certain airplanes) 
and the inboard (for all airplanes) midspar fittings, and cleaning the 
midspar fittings.
    This AD continues to require repetitive detailed visual borescope 
inspections to detect cracking, corrosion, and fracturing of the lower 
horizontal clevis of the inboard and outboard strut midspar fittings. 
Replacement of discrepant fittings with new fittings is also required, 
or rework, as applicable. This AD adds ultrasonic/detailed visual 
inspections as an alternative method of accomplishing those 
inspections.
    This AD adds repetitive ultrasonic/detailed visual inspections of 
the upper horizontal clevis of the inboard and outboard strut midspar 
fittings, and replacement of discrepant fittings with new fittings, or 
rework, if necessary.
    For airplanes on which any cracking, corrosion, or fracturing is 
detected that is outside certain limits, this AD requires 
accomplishment of the strut/wing modification, replacement of the 
midspar fittings of the strut with new fittings, or repair in 
accordance with a method approved by the FAA, as applicable.
    Accomplishment of the strut/wing modification constitutes 
terminating action for the repetitive inspection requirements of this 
AD.
    Certain actions are required to be accomplished in accordance with 
Boeing Alert Service Bulletin 747-A2179, Revision 1, dated November 27, 
1996, described previously. Certain other actions are required to be 
accomplished in accordance with a method approved by the FAA.

Difference Between This AD and the Alert Service Bulletin

    Operators should note that, while the alert service bulletin 
advises operators to contact the manufacturer if the damaged area is 
beyond the specified limits, this AD requires operators to repair any 
such damage in accordance with a method approved by the FAA, Transport 
Airplane Directorate.
    Operators also should note that airplanes on which reworking of the 
upper and lower horizontal clevis of the midspar fittings has been 
accomplished in accordance with Boeing Service Bulletin 747-54-2118, 
dated July 25, 1986, have not been included in the effectivity of the 
alert service bulletin. However, the FAA has determined that, in light 
of the recent reports of cracking, the rework is not sufficient to 
provide adequate assurance of permanent correction of the unsafe 
condition addressed by this action. Therefore, the FAA has removed the 
provision for reworking from AD 96-25-01 as an optional terminating 
action for the repetitive inspection requirements of this AD.
    Additionally, Boeing Alert Service Bulletin 747-54A2179, Revision 
1, dated November 27, 1996, describes the replacement of the midspar 
fittings of the strut as an optional method of eliminating the 
repetitive inspections. The alert service bulletin also references 
replacement of the midspar fittings of the strut in accordance with 
either the alert service bulletin or Boeing Service Bulletin 747-54-
2118, Revision 4, dated May 11, 1989, as an optional terminating 
action, which eliminates the need for repetitive inspections.
    However, the FAA has determined that, in light of the recent 
reports of cracking discussed previously, neither the replacement nor 
the rework is sufficient to provide adequate assurance of permanent 
correction of the unsafe condition. Therefore, the FAA also has removed 
those optional terminating actions from this AD.

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-70-AD.'' The

[[Page 31334]]

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 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 39-5836 (53 FR 
2005, January 26, 1988) and amendment 39-9842 (61 FR 66201, December 
17, 1996), and by adding a new airworthiness directive (AD), 
amendment 39-10045, to read as follows:
97-12-03 Boeing: Amendment 39-10045. Docket 97-NM-70-AD. Supersedes 
AD 87-04-13 R1, amendment 39-5836; and AD 96-25-01, amendment 39-
9842.
    Applicability: Model 747 series airplanes as listed in Boeing 
Alert Service Bulletin 747-54A2179, Revision 1, dated November 27, 
1996; certificated in any category, except for airplanes on which 
the strut/wing modification has been accomplished in accordance with 
the following Boeing alert service bulletins:
    1. Boeing Alert Service Bulletin 747-54A2157, dated January 12, 
1995; Revision 1, dated August 3, 1995; or Revision 2, dated 
November 14, 1996;
    2. Boeing Alert Service Bulletin 747-54A2158, dated November 30, 
1994; Revision 1, dated August 17, 1995; or Revision 2, dated August 
15, 1996; or
    3. Boeing Alert Service Bulletin 747-54A2159, dated November 3, 
1994; Revision 1, dated June 1, 1995; or Revision 2, dated March 14, 
1996.
    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 (n) 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 drooping of the strut at the strut-to-wing interface, 
and consequent separation of the engine and strut from the airplane 
due to cracking or fracturing of the midspar fitting clevis, 
accomplish the following:

Restatement of Requirements of AD 96-25-01

    (a) For all airplanes: Except as provided by paragraph (d) of 
this AD, perform a detailed visual borescope inspection to detect 
cracking, corrosion, and/or fracturing of the lower horizontal 
clevis of both midspar fittings of the inboard struts, in accordance 
with Boeing Alert Service Bulletin 747-54A2179, dated June 27, 1996, 
or Revision 1, dated November 27, 1996, at the time specified in 
paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, as 
applicable.
    (1) For airplanes identified as Group 1 or Group 6 in the alert 
service bulletin: Perform the initial inspection at the time 
specified in paragraph (a)(1)(i) or (a)(1)(ii), as applicable. 
Thereafter, repeat this inspection at intervals not to exceed every 
150 flight cycles, or every 3 months, whichever occurs first. (i) 
Within 150 flight cycles or 60 days after January 2, 1997 (the 
effective date of AD 96-25-01, amendment 39-9842), whichever occurs 
first. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 500 flight cycles prior to January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 500 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (2) For airplanes identified as Group 2 or Group 4 in the alert 
service bulletin: Perform the initial inspection at the time 
specified in paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as 
applicable. Thereafter, repeat this inspection at intervals not to 
exceed every 300 flight cycles or 6 months, whichever occurs first.
    (i) Within 150 flight cycles or 60 days after January 2, 1997, 
whichever occurs first. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 1,000 flight cycles prior to January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 1,000 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (3) For airplanes identified as Group 3 in the alert service 
bulletin: Perform the initial inspection at the time specified in 
paragraph (a)(3)(i) or (a)(3)(ii) of this AD, as applicable. 
Thereafter, repeat this inspection at intervals not to exceed every 
350 flight cycles or 6 months, whichever occurs first.
    (i) Within 150 flight cycles or 60 days after January 2, 1997, 
whichever occurs first. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 1,000 flight cycles prior to January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 1,000 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (4) For airplanes identified as Group 5 in the alert service 
bulletin: Perform the initial inspection at the time specified in 
paragraph (a)(4)(i) or (a)(4)(ii) of this AD, as applicable. 
Thereafter, repeat the inspection at intervals not to exceed every 
300 flight cycles or 6 months, whichever occurs first.
    (i) Within 150 flight cycles or 60 days after January 2, 1997, 
whichever occurs first.
    (ii) For airplanes on which terminating action has been 
accomplished within 800 flight cycles prior to January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 800 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (b) For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 747-54A2179, dated June 27, 1996, or Revision 1, dated 
November 27, 1996: Except as provided by paragraph (e) of this AD, 
perform a detailed visual borescope inspection to detect cracking, 
corrosion, and/or fracturing of the lower horizontal clevis of both 
midspar fittings of the outboard struts, in accordance with Boeing 
Alert Service Bulletin 747-54A2179, dated June 27, 1996, or Revision 
1, dated November 27, 1996, at the time specified in paragraph 
(b)(1) or (b)(2) of this

[[Page 31335]]

AD, as applicable. Thereafter, repeat the inspection at intervals 
not to exceed every 300 flight cycles or 6 months, whichever occurs 
first.
    (1) Within 200 flight cycles or 60 days after January 2, 1997, 
whichever occurs first. Or
    (2) For airplanes on which the terminating action has been 
accomplished within the last 1,000 flight cycles prior to January 2, 
1997, in accordance with Boeing Service Bulletin 747-54-2118, 
Revision 1, dated May 21, 1987; Revision 2, dated April 21, 1988; 
Revision 3, dated September 29, 1988; or Revision 4, dated May 11, 
1989: Perform the inspection within 1,000 flight cycles or 12 months 
after January 2, 1997, whichever occurs first.

New Requirements of this AD

    (c) For all airplanes: After the effective date of this AD, 
prior to the accomplishment of each inspection required by paragraph 
(a), (b), (d), or (e), of this AD, remove the sealant common to the 
lower leg of the horizontal clevis of the inboard (for all 
airplanes) midspar fittings, and the outboard (for Groups 1 and 6 
airplanes) and clean the midspar fittings, in accordance with Boeing 
Alert Service Bulletin 747-54A2179, Revision 1, dated November 27, 
1996. Prior to further flight following accomplishment of these 
actions, apply corrosion inhibitive compound BMS 3-23 to any area 
where the original sealant was removed or disturbed, in accordance 
with Boeing Standard Operational Procedures (BSOP) 20-41-05 for 
Model 747 series airplanes.
    (d) Accomplishment of the actions specified in this paragraph is 
an alternative to compliance with paragraph (a) of this AD. Perform 
an ultrasonic/detailed visual inspection to detect cracking, 
corrosion, and/or fracturing of the lower horizontal clevis of both 
midspar fittings of the inboard struts, in accordance with Boeing 
Alert Service Bulletin 747-54A2179, Revision 1, dated November 27, 
1996, at the time specified in paragraph (d)(1), (d)(2), (d)(3), or 
(d)(4) as applicable.
    (1) For airplanes identified as Group 1 or 6 in the alert 
service bulletin: Perform the inspections at the time specified in 
paragraph (d)(1)(i) or (d)(1)(ii) of this AD. Thereafter, repeat the 
inspections at intervals not to exceed every 1,000 flight cycles or 
18 months, whichever occurs first.
    (i) Within 150 flight cycles or 3 months after accomplishing the 
last inspection required by paragraph (b) of AD 96-25-01 or 
paragraph (a) of this AD.
    (ii) For airplanes on which terminating action has been 
accomplished within 500 flight cycles after January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 500 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (2) For airplanes identified as Group 2 or 4 in the alert 
service bulletin: Perform the inspection at the time specified in 
paragraph (d)(2)(i) or (d)(2)(ii) of this AD, as applicable. 
Thereafter, repeat this inspection at intervals not to exceed every 
1,500 flight cycles or 18 months, whichever occurs first.
    (i) Within 300 flight cycles or 6 months after accomplishing the 
last inspection required by paragraph (b) of AD 96-25-01 or 
paragraph (a) of this AD. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 1,000 flight cycles after January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 1,000 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (3) For airplanes identified as Group 3 in the alert service 
bulletin: Perform the inspection at the time specified in paragraph 
(d)(3)(i) or (d)(3)(ii) of this AD, as applicable. Thereafter, 
repeat the inspection at intervals not to exceed every 2,500 flight 
cycles or 18 months, whichever occurs first.
    (i) Within 350 flight cycles or 6 months after accomplishing the 
last inspection required by paragraph (b) of AD 96-25-01 or 
paragraph (a) of this AD. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 1,000 flight cycles after January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 1,000 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (4) For airplanes identified as Group 5 in the alert service 
bulletin: Perform the inspection at the time specified in paragraph 
(d)(4)(i) or (d)(4)(ii) of this AD, as applicable. Thereafter, 
repeat the inspection at intervals not to exceed every 1,500 flight 
cycles or 18 months, whichever occurs first.
    (i) Within 300 flight cycles or 6 months after accomplishing the 
last inspection required by paragraph (b) of AD 96-25-01 or 
paragraph (a) of this AD. Or
    (ii) For airplanes on which terminating action has been 
accomplished within 800 flight cycles after January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the initial inspection within 800 flight cycles or 12 months after 
January 2, 1997, whichever occurs first.
    (e) For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 747-54A2179, Revision 1, dated November 27, 1996: 
Accomplishment of the actions specified in this paragraph is an 
alternative to compliance with paragraph (b) of this AD. Perform an 
ultrasonic/detailed visual inspection to detect cracking, corrosion, 
and/or fracturing of the lower horizontal clevis of both midspar 
fittings of the outboard struts, in accordance with Boeing Alert 
Service Bulletin 747-54A2179, Revision 1, dated November 27, 1996, 
at the time specified in paragraph (e)(1) or (e)(2) of this AD, as 
applicable. Thereafter, repeat the inspection at intervals not to 
exceed every 2,000 flight cycles or 18 months, whichever occurs 
first.
    (1) Within 300 flight cycles or 6 months after accomplishing the 
last inspection required by paragraph (c) of AD 96-25-01 or 
paragraph (b) of this AD. Or
    (2) For airplanes on which terminating action has been 
accomplished within 1,000 flight cycles after January 2, 1997, in 
accordance with Boeing Service Bulletin 747-54-2118, Revision 1, 
dated May 21, 1987; Revision 2, dated April 21, 1988; evision 3, 
dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform 
the inspection within 1,000 flight cycles or 12 months after January 
2, 1997, whichever occurs first.
    (f) For all airplanes: After the effective date of this AD, 
prior to the accomplishment of each inspection required by 
paragraphs (g), (h), or (i), of this AD, remove the sealant of the 
upper horizontal leg surface and clean the midspar fittings in 
accordance with Boeing Alert Service Bulletin 747-54A2179, Revision 
1, dated November 27, 1996. Prior to further flight following 
accomplishment of these actions: Restore the sealant of the upper 
horizontal leg surface in accordance with the alert service 
bulletin.
    (g) For all airplanes: Within 90 days after the effective date 
of this AD, perform an ultrasonic/detailed visual inspection to 
detect cracking, corrosion, and/or fracturing of the upper 
horizontal clevis of both midspar fittings of the inboard struts, in 
accordance with Boeing Alert Service Bulletin 747-54A2179, Revision 
1, dated November 27, 1996. Repeat the ultrasonic/detailed visual 
inspection thereafter at the time specified in paragraph (g)(1), 
(g)(2), or (g)(3), as applicable.
    (1) For airplanes identified as Group 1 or 6 in the alert 
service bulletin: Repeat at intervals not to exceed every 1,000 
flight cycles or 18 months, whichever occurs first.
    (2) For airplanes identified as Group 2, 4, or 5 in the alert 
service bulletin: Repeat at intervals not to exceed every 1,500 
flight cycles or 18 months, whichever occurs first.
    (3) For airplanes identified as Group 3 in the alert service 
bulletin: Repeat at intervals not to exceed every 2,500 flight 
cycles or 18 months, whichever occurs first.
    (h) For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 747-54A2179, Revision 1, dated November 27, 1996: Within 90 
days after the effective date of this AD, perform an ultrasonic/
detailed visual inspection of the upper horizontal clevis of both 
midspar fittings of the outboard strut to detect cracking, 
corrosion, and/or fracturing, in accordance with the alert service 
bulletin. Repeat the inspection thereafter at intervals not to 
exceed every 2,000 flight cycles or 18 months, whichever occurs 
first.
    (i) For airplanes specified in paragraph (i)(1) or (i)(2) of 
this AD: Perform the actions specified in paragraph (a), (b), (d), 
(e), (f), (g), or (h) of this AD, as applicable, at the time 
specified in paragraph (i)(1) or (i)(2) of this AD, as applicable. 
Thereafter, perform the repetitive inspections at the time specified 
in paragraph (a), (b), (d), (e), (f), (g), or (h) of this AD, as 
applicable.
    (1) For airplanes on which rework of all the fastener holes has 
been accomplished in

[[Page 31336]]

accordance with Boeing Alert Service Bulletin 747-54A2179, dated 
June 27, 1996, Revision 1, dated November 27, 1996, or Boeing 
Service Bulletin 747-54-2118, dated July 25, 1986: Perform the 
initial inspection at the later of the times specified in paragraphs 
(i)(1)(i) and (i)(1)(ii) of this AD.
    (i) Prior to the accumulation of 3,000 total landings, or within 
3 years after accomplishment of the rework, whichever occurs first. 
Or
    (ii) Within 90 days after the effective date of this AD.
    (2) For airplanes on which the midspar fittings have been 
replaced in accordance with Boeing Alert Service Bulletin 747-
54A2179, Revision 1, dated November 27, 1996, or Boeing Service 
Bulletin 747-54-2118, dated July 25, 1986; Revision 1, dated May 21, 
1987; Revision 2, dated April 21, 1988; Revision 3, dated September 
29, 1988; or Revision 4, dated May 11, 1989: Perform the initial 
inspection at the later of the times specified in paragraphs 
(i)(2)(i) and (i)(2)(ii) of this AD.
    (i) Prior to the accumulation of 5,000 landings, or within 5 
years after the fitting has been replaced, whichever occurs first. 
Or
    (ii) Within 90 days after the effective date of this AD.
    (j) For all airplanes: If any cracking, corrosion, or fracturing 
is detected during any inspection required by this AD that is 
outside the limits specified in Boeing Alert Service Bulletin 757-
54A2179, Revision 1, dated November 27, 1996, and the damaged area 
is within the area limits specified in the alert service bulletin, 
prior to further flight, accomplish the requirements of paragraph 
(j)(1) or (j)(2) of this AD.
    (1) Accomplish the strut/wing modification specified in 
paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD, as 
applicable. Following accomplishment of that action, no further 
action is required by this AD.
    (i) For airplanes equipped with Rolls Royce Model RB211 series 
engines: Accomplish the strut/wing modification in accordance with 
Boeing Alert Service Bulletin 747-54A2157, Revision 2, dated 
November 14, 1996. Accomplishment of this paragraph terminates the 
requirements of AD 95-13-05, amendment 39-9285.
    (ii) For airplanes equipped with General Electric Model CF6-45 
or -50 series engines, or Pratt & Whitney Model JT9D-70 series 
engines: Accomplish the strut/wing modification in accordance with 
Boeing Alert Service Bulletin 747-54A2158, Revision 2, dated August 
15, 1996. Accomplishment of this paragraph terminates the 
requirements of AD 95-13-07, amendment 39-9287.
    (iii) For airplanes equipped with Pratt & Whitney Model JT9D 
series engines (excluding Model JT9D-70 engines): Accomplish the 
strut/wing modification in accordance with Boeing Alert Service 
Bulletin 747-54A2159, Revision 2, dated March 14, 1996. 
Accomplishment of this paragraph terminates the requirements of AD 
95-10-16, amendment 39-9233.
    (2) Replace the midspar fittings of the strut with new fittings 
in accordance with Boeing Alert Service Bulletin 747-54A2179, 
Revision 1, dated November 27, 1996. Repeat the inspections 
thereafter at the intervals specified in paragraph (i)(2) of this 
AD.
    (k) If any cracking, corrosion, or fracturing is detected during 
any inspection required by this AD that is outside the limits 
specified in Boeing Alert Service Bulletin 747-54A2179, Revision 1, 
dated November 27, 1996, and the damaged area is outside the area 
limits specified in the alert service bulletin, prior to further 
flight, accomplish the requirements of either paragraph (j)(1) or 
(j)(2) of this AD, or repair in accordance with a method approved by 
the Manager, Seattle ACO.
    (l) For all airplanes: If any cracking, corrosion, or fracturing 
is detected during any inspection required by this AD and it is 
within the limits specified in Boeing Alert Service Bulletin 757-
54A2179, Revision 1, dated November 27, 1996: Prior to further 
flight, accomplish the requirements of paragraph (l)(1), (l)(2), 
(l)(3), or (l)(4) of this AD.
    (1) Rework any discrepant area in accordance with the alert 
service bulletin. Following the rework, repeat the actions required 
by paragraph (a), (b), (d), (e), (f), (g), or (h) of this AD, as 
applicable, at the intervals specified in those paragraphs.
    (2) Rework all the fastener holes in accordance with the alert 
service bulletin. Within 3,000 flight cycles or 3 years after 
reworking all the fastener holes, whichever occurs first: Repeat the 
actions required by paragraph (i)(1) of this AD, and accomplish the 
repetitive inspections required by paragraph (i) of this AD.
    (3) Replace the midspar fittings in accordance with the alert 
service bulletin. Within 5,000 flight cycles or 5 years after 
replacing the midspar fittings, whichever occurs first: Repeat the 
actions required by paragraph (i)(2) of this AD, and accomplish the 
repetitive inspections required by paragraph (i) of this AD.
    (4) Accomplish the strut/wing modification specified in 
paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD, as 
applicable. Following accomplishment of that action, no further 
action is required by this AD.
    (m) Accomplishment of the strut/wing modification specified in 
paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD 
constitutes terminating action for the requirements of this AD.
    (n) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.
    (o) 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.
    (p) Certain actions shall be done in accordance with the Boeing 
Alert Service Bulletins listed in the following table. The 
incorporation by reference of those documents 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 the dates specified in 
the table below:

------------------------------------------------------------------------
                                              Approval Date and Federal 
   Referenced Service Bulletin and Date           Register Citation     
------------------------------------------------------------------------
747-54A2157, January 12, 1995.............  July 28, 1995 (60 FR 33333, 
                                             June 28, 1995).            
747-54A2158, November 30, 1994............  July 28, 1995 (60 FR 33336, 
                                             July 28, 1995).            
747-54A2159, November 3, 1994.............  June 21, 1995 (60 FR 27008, 
                                             May 22, 1995).             
------------------------------------------------------------------------

    Certain other actions shall be done in accordance with the Boeing 
Alert Service Bulletins listed in the following table. The 
incorporation by reference of those documents was approved previously 
by the Director of the Federal Register on January 22, 1997 (61 FR 
66201, December 12, 1996), in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51:

------------------------------------------------------------------------
                                       Revision                         
     Referenced Service Bulletin        Level              Date         
------------------------------------------------------------------------
747-54A2179.........................  Original   June 27, 1996.         
747-54A2157.........................         1   Aug. 3, 1995.          
747-54A2157.........................         2   Nov. 14, 1996.         
747-54A2158.........................         1   Aug. 17, 1995.         
747-54A2158.........................         2   Aug. 15, 1996.         
747-54A2159.........................         1   June 1, 1995.          
747-54A2159.........................         2   Mar. 14, 1996.         
------------------------------------------------------------------------

    Certain other actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-54A2179, Revision 1, dated November 27, 1996. This 
incorporation by reference 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.
    (q) This amendment becomes effective on June 24, 1997.

    Issued in Renton, Washington, on May 30, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-14769 Filed 6-6-97; 8:45 am]
BILLING CODE 4910-13-U