[Federal Register Volume 59, Number 244 (Wednesday, December 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31328]


[[Page Unknown]]

[Federal Register: December 21, 1994]


                                                   VOL. 59, NO. 244

                                       Wednesday, December 21, 1994

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-187-AD]

 

Airworthiness Directives; Boeing Model 747 Series Airplanes 
Equipped With Pratt & Whitney Model JT9D Series Engines (Excluding 
Model JT9D-70 Engines)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747 series 
airplanes. This proposal would require modification of the nacelle 
strut and wing structure, inspections and checks to detect 
discrepancies, and correction of discrepancies. This proposal is 
prompted by the development of a modification of the strut and wing 
structure that improves the fail-safe capability and durability of the 
strut-to-wing attachments, and reduces reliance on inspections of those 
attachments. The actions specified by the proposed AD are intended to 
prevent failure of the strut and subsequent loss of the engine.

DATES: Comments must be received by February 16, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-187-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule 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: Tim Backman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2776; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-187-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 94-NM-187-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056

Discussion -

    The FAA has received numerous reports of fatigue cracking and/or 
corrosion in the strut-to-wing attachments on Boeing Model 747 series 
airplanes. In two cases, such cracking resulted in the failure of a 
strut load path and the subsequent loss of the number 3 engine and 
strut. In both cases, catastrophic accidents occurred when the number 3 
engine and strut separated from the wing of the airplane and struck the 
number 4 engine, causing it to separate from the airplane. 
Investigation into the cause of these accidents and other reported 
incidents revealed not only that fatigue cracks and corrosion in the 
strut-to-wing attachments, if not detected and corrected in a timely 
manner, can result in failure of the strut and subsequent separation of 
the engine from the airplane, but that the structural fail-safe 
capability of the strut-to-wing attachment is inadequate on these 
airplanes.
    The FAA has previously issued 17 AD's that address various problems 
associated with the strut attachment assembly on Boeing Model 747 
series airplanes. These AD's have required, among other things, 
inspections of the strut, strut-to-wing attachment structure, and wing 
backup structure of Model 747 series airplanes that are equipped with 
Pratt & Whitney Model JT9D series engines (excluding Model JT9D-70 
series engines).

Explanation of Service Information

    Boeing recently has developed a modification of the strut-to-wing 
attachment structure installed on certain Model 747 series airplanes 
equipped with Pratt & Whitney Model JT9D series engines (excluding 
Model JT9D-70 engines) that significantly improves the load-carrying 
capability and durability of the strut-to-wing attachments. Such 
improvement also will substantially reduce the possibility of fatigue 
cracking and corrosion from developing in the attachment assembly.
    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-54A2159, dated November 3, 1994, which describes procedures for 
modification of the nacelle strut and wing structure. This modification 
entails the following:
    1. Providing a new fail-safe load path by installing a new dual 
side load fitting to the strut and the underwing structure and the 
associated wing back-up fitting, front spar post, and side links;
    2. Strengthening the strut by installing a new midspar web and a 
new lower spar web and/or channel stiffener;
    3. Strengthening the internal wing structure by installing a new 
stiffener at the wing midspar;
    4. Improving the strut-to-wing attachments by installing new 
stainless steel midspar fittings on the strut, replacing aluminum 
fittings with new titanium midspar underwing fittings, and replacing 
the upper link and the diagonal brace;
    5. Enhancing the diagonal brace underwing fitting by installing 
certain new nuts and tension bolts; and
    6. Modifying the electrical wiring and hydraulics by rerouting 
certain wire bundles around the new dual side load fitting and 
installing new hydraulic tubes.
    This alert service bulletin specifies that the modification of the 
nacelle strut and wing structure is to be accomplished prior to, or 
concurrently with, the terminating actions described in the service 
bulletins listed in paragraph I.C., Table 2, ``Prior or Concurrent 
Service Bulletins,'' on page 13 of this alert service bulletin. These 
terminating actions include the following:
    1. Replacement of the diagonal brace, midspar, and upper link 
fusepins with new third generation 15-5 corrosion-resistant steel 
fusepins;
    2. Replacement of the diagonal brace strut and wing attachment 
fittings;
    3. Strengthening of the wing front spar; and
    4. Replacement of the forward engine mounting nut.
    Paragraph III, NOTES 8, 9, 10, and 11 of the Accomplishment 
Instructions on pages 149 and 150 of the alert service bulletin also 
describe procedures for inspections and checks to detect discrepancies 
of the adjacent structure, and correction of any discrepancies.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modification of the nacelle strut and wing 
structure, inspections and checks to detect discrepancies in the 
adjacent structure, and correction of discrepancies. The actions would 
be required to be accomplished in accordance with the alert service 
bulletin described previously.
    The FAA has determined that long term continued operational safety 
will be better assured by design changes to remove the source of the 
problem, rather than by repetitive inspections. Long term inspections 
may not be providing the degree of safety assurance necessary for the 
transport airplane fleet. This, coupled with a better understanding of 
the human factors associated with numerous continual inspections, has 
led the FAA to consider placing less emphasis on inspections and more 
emphasis on design improvements. The proposed modification requirement 
is in consonance with these considerations.
    Accomplishment of the modification of the nacelle strut and wing 
structure would terminate the inspections currently required by the 
following AD's:

----------------------------------------------------------------------------------------------------------------
          AD No.             Amendment No.      Federal Register citation             Date of publication       
----------------------------------------------------------------------------------------------------------------
94-17-17-.................        39-9012-  59 FR 44903-.....................  August 31, 1994.                 
94-10-05-.................        39-8912-  59 FR 25288-.....................  May 16, 1994.                    
93-17-07-.................        39-8678-  58 FR 45827-.....................  August 31, 1993.                 
93-03-14-.................        39-8518-  58 FR 14513-.....................  March 18, 1993.                  
92-24-51-.................        39-8439-  57 FR 60118-.....................  December 18, 1992.               
92-07-11-.................        39-8207-  57 FR 10415-.....................  March 26, 1992.                  
90-20-20-.................        39-6725-  55 FR 37859-.....................  September 14, 1990.              
90-17-18-.................        39-6702-  55 FR 33279-.....................  August 15, 1990.                 
89-07-15-.................        39-6167-  54 FR 11693-.....................  March 22, 1989.                  
87-04-13 R1-..............        39-5546-  52 FR 3421-......................  February 4, 1987.                
86-08-03-.................        39-5289-  51 FR 12836-.....................  April 16, 1986.                  
86-07-06-.................        39-5270-  51 FR 10821-.....................  March 31, 1986.                  
86-05-11-.................        39-5255-  51 FR 8479-......................  March 12, 1986.                  
86-23-01-.................        39-5450-  51 FR 37712-.....................  October 24, 1986.                
82-22-02-.................        39-4476-  47 FR 46842-.....................  October 21, 1982.                
80-08-02-.................        39-3738-  45 FR 24450-.....................  April 10, 1980.                  
79-17-07-.................        39-3533-  44 FR 50033-.....................  August 27, 1979.                 
----------------------------------------------------------------------------------------------------------------

    The compliance time for accomplishing the proposed modification has 
been broken out into separate groupings. Airplanes that are younger 
than 15 years must be modified within 56 months after the effective 
date of the AD, and airplanes that are 15 years and older must be 
modified within 32 months after the effective date of the AD. The FAA's 
intent is to require modification of older airplanes at an earlier 
date, since they are more likely to be subject to fatigue cracking and 
corrosion. -
    The FAA recognizes that the modifications described in the service 
bulletins listed in paragraph I.D., ``Compliance,'' on page 17 of 
Boeing Alert Service Bulletin 747-54A21
59, dated November 3, 1994, upgrades the structural integrity of the 
strut. These modifications include replacement of the upper link, lower 
spar fitting, diagonal brace, and mounting nut for the forward engine. 
Additionally, these modifications entail rework of the midspar fitting 
lugs and fitting attachments; and include the installation of third 
generation fuse pins at the strut midspar, diagonal brace, and wing-to-
strut attachments of the upper link. The FAA finds that the proposed 
compliance time (for installation of the proposed modification of the 
nacelle strut and wing structure) for airplanes on which these other 
modifications previously have been accomplished may be extended without 
compromising the safety of the fleet. Therefore, the FAA has further 
divided the proposed compliance times for airplanes that are 15 years 
or older to segregate the requirements of those airplanes that have and 
have not been modified previously.
    For example, for airplanes on which the modifications described in 
the service bulletins referenced by paragraph I.D., ``Compliance,'' on 
page 17 of the Boeing alert service bulletin, have been accomplished, 
modification of the nacelle strut and wing structure would be required 
within 56 months; while, for airplanes on which the modifications 
referenced by paragraph I.D. have not been accomplished, modification 
of the nacelle strut and wing structure would be required within 32 
months.
    Further, the FAA acknowledges the work that has been accomplished 
previously by creating separate groupings for those airplanes on which 
certain, but not all, of the modifications have been accomplished. 
Therefore, if the modification described in Boeing Service Bulletin 
747-54-2118, dated July 25, 1986 (which is one of the service bulletins 
referenced by paragraph I.D., ``Compliance,'' on page 17 of the Boeing 
alert service bulletin), has not been accomplished, but all other 
modifications referenced by paragraph I.D. have been accomplished, the 
FAA's intent is to allow operators of these airplanes to continue to 
perform the inspections of the fastener holes that currently are 
required by AD 87-04-13 R1, amendment 39-5546 (52 FR 3421, February 4, 
1987). However, those inspections must be performed at a reduced 
interval of 1,000 landings, until such time that the proposed 
modification of the nacelle strut and wing structure is accomplished. 
For these airplanes, modification of the nacelle strut and wing 
structure would be required within 56 months after the effective date 
of this AD.
    Similarly, if rework of the midspar fitting lugs or spring beam aft 
lugs described in Boeing Alert Service Bulletin 747-54A2152, dated 
December 23, 1992, or Revision 1, dated July 15, 1993, has not been 
accomplished, but all other modifications referenced by paragraph I.D. 
have been accomplished, then the rework should be done in accordance 
with Revision 2 of that alert service bulletin. Operators of these 
airplanes that have already reworked the midspar fitting lugs or spring 
beam aft lugs in accordance with the original issue or Revision 1 of 
that alert service bulletin can receive an extension of the compliance 
time to 56 months, provided that ultrasonic inspections are performed 
(to detect cracking of the inboard and outboard midspar fitting lugs or 
spring beam aft lugs of each strut) within 2,500 landings or 3 years 
since accomplishment of the rework, whichever occurs earlier, in 
accordance with Revision 2 of Boeing Alert Service Bulletin 747-
54A2152, dated September 16, 1993. For these airplanes, repetitive 
inspections would be required at intervals not to exceed 500 landings 
for inboard struts and 1,000 landings for outboard struts. The FAA has 
approved Revision 2 of this alert service bulletin as an alternative 
method of compliance to accomplish the requirements of AD 93-17-07, 
amendment 39-8678 (58 FR 45827, August 31, 1993), which references 
Revision 1 and the original issue of that alert service bulletin as the 
appropriate sources of service information to perform this ultrasonic 
inspection. The FAA acknowledges that this compliance time is earlier 
than that required by AD 93-17-07; however, performance of this 
inspection would defer modification of the nacelle strut and wing 
structure until 56 months after the effective date of this AD for these 
airplanes.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this requirement.

Cost Estimate

    There are approximately 600 Model 747 series airplanes equipped 
with Pratt & Whitney Model JT9D series engines (excluding Model JT9D-70 
engines) of the affected design in the worldwide fleet. The FAA 
estimates that 146 airplanes of U.S. registry would be affected by this 
proposed AD.
    The proposed modification may take as many as 7,700 to 8,892 work 
hours to accomplish, depending upon the configuration of the airplane. 
The manufacturer would incur the cost of labor, on a pro-rated basis, 
with 20 years being the expected life of these airplanes. The total 
cost impact of the proposed AD on U.S. operators is based on the median 
age for the fleet of Model 747 series airplanes equipped with Pratt & 
Whitney Model JT9D series engines, which is estimated to be 15 years. 
The average labor rate is estimated to be $60 per work hour. Required 
parts would be supplied by the manufacturer at no cost to the operator. 
Based on these figures, the cost impact of this proposal on U.S. 
operators is estimated to be between $50,589,000 ($346,500 per 
airplane) and $58,420,440 ($400,140 per airplane).
    This cost impact figure does not reflect the cost of the 
terminating actions described in the service bulletins listed in 
paragraph I.C., Table 2, ``Prior or Concurrent Service Bulletins,'' on 
page 13 of Boeing Alert Service Bulletin 747-54A2159, dated November 3, 
1994, that are proposed to be accomplished prior to or concurrently 
with the modification of the nacelle strut and wing structure. Since 
some operators may have accomplished certain modifications on some or 
all of the airplanes in its fleet, while other operators may not have 
accomplished any of the modifications on any of the airplanes in its 
fleet, the FAA is unable to provide a reasonable estimate of the cost 
of accomplishing the terminating actions described in the service 
bulletins listed in Table 2 of the Boeing alert service bulletin. As 
indicated earlier in this preamble, the FAA invites comments 
specifically on the overall economic aspects of this proposed rule. Any 
data received via public comments to this notice will aid the FAA in 
developing an accurate accounting of the cost impact of the rule.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.
    The FAA recognizes that the obligation to maintain aircraft in an 
airworthy condition is vital, but sometimes expensive. Because AD's 
require specific actions to address specific unsafe conditions, they 
appear to impose costs that would not otherwise be borne by operators. 
However, because of the general obligation of operators to maintain 
aircraft in an airworthy condition, this appearance is deceptive. 
Attributing those costs solely to the issuance of this AD is 
unrealistic because, in the interest of maintaining safe aircraft, 
prudent operators would accomplish the required actions even if they 
were not required to do so by the AD.
    A full cost-benefit analysis has not been accomplished for this 
proposed AD. As a matter of law, in order to be airworthy, an aircraft 
must conform to its type design and be in a condition for safe 
operation. The type design is approved only after the FAA makes a 
determination that it complies with all applicable airworthiness 
requirements. In adopting and maintaining those requirements, the FAA 
has already made the determination that they establish a level of 
safety that is cost-beneficial. When the FAA, as in this proposed AD, 
makes a finding of an unsafe condition, this means that the original 
cost-beneficial level of safety is no longer being achieved and that 
the proposed actions are necessary to restore that level of safety. 
Because this level of safety has already been determined to be cost-
beneficial, a full cost-benefit analysis for this proposed AD would be 
redundant and unnecessary.

Regulatory Impact

    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

Boeing: Docket 94-NM-187-AD.

    Applicability: Model 747 series airplanes having line positions 
001 through 814 inclusive, equipped with Pratt & Whitney Model JT9D 
series engines (excluding Model JT9D-70 engines), certificated in 
any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must use the authority 
provided in paragraph (d) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the strut and subsequent loss of the 
engine, accomplish the following:
    (a) Accomplish the modification of the nacelle strut and wing 
structure in accordance with Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, at the time specified in either 
paragraph (a)(1) or (a)(2) of this AD, as applicable. All of the 
terminating actions described in the service bulletins listed in 
paragraph I.C., Table 2, ``Prior or Concurrent Service Bulletins,'' 
on page 13 of Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994, must be accomplished in accordance with those 
service bulletins prior to or concurrently with the accomplishment 
of the modification of the nacelle strut and wing structure required 
by this paragraph.
    (1) For airplanes that are younger than 15 years on the 
effective date of this AD, within 56 months after the effective date 
of this AD, accomplish the modification.
    (2) For airplanes that are 15 years or older on the effective 
date of this AD, accomplish the modification, and other required 
actions, at the time specified in paragraph (a)(2)(i), (a)(2)(ii), 
(a)(2)(iii), (a)(2)(iv), or (a)(2)(v) of this AD, as applicable.
    (i) For airplanes on which all of the modifications described in 
the service bulletins referenced by paragraph I.D., ``Compliance,'' 
on page 17 of Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994, have been accomplished: Within 56 months after the 
effective date of this AD, accomplish the modification of the 
nacelle strut and wing structure and perform the inspections of the 
adjacent structure that has not been replaced by the modification.

    Note 2: Paragraph I.D., ``Compliance,'' on page 17 of Boeing 
Alert Service Bulletin 747-54A2159, dated November 3, 1994, 
references the following Boeing service bulletins. Subsequent 
revisions of the following service bulletins are acceptable and 
preferred for accomplishment of the modifications described therein:

------------------------------------------------------------------------
  Service bulletin No.        Revision level               Date         
------------------------------------------------------------------------
747-54-2027-...........  1......................  February 23, 1973.    
747-54-2030-...........  Initial release........  February 23, 1973.    
747-54-2062-...........  5......................  June 1, 1984.         
747-54A2069-...........  6......................  October 22, 1982.     
747-54-2118-...........  Initial release........  July 25, 1986.        
747-54-2123-...........  1......................  March 1, 1990.        
747-54A2151-...........  Initial release........  October 6, 1992.      
747-54A2152-...........  2......................  September 16, 1993.   
747-54A2155-...........  Initial release........  September 23, 1993.   
747-57A2235-...........  Initial release........  June 27, 1986.        
747-71A2269-...........  1......................  July 7, 1994.         
------------------------------------------------------------------------

    (ii) For airplanes on which all of the modifications described 
in the service bulletins referenced by paragraph I.D., 
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, have been accomplished, excluding 
the modification described in Boeing Service Bulletin 747-54-2118, 
dated July 25, 1986:
    (A) Within 56 months after the effective date of this AD, 
accomplish the modification of the nacelle strut and wing structure 
and perform the inspections of the adjacent structure that has not 
been replaced by the modification.
    (B) Repeat the ultrasonic inspections to detect cracking of the 
aft-most two fastener holes in both strut midspar fittings on the 
inboard and outboard nacelle struts, as required by AD 87-04-13 R1 
at intervals not to exceed 1,000 landings, in accordance with Boeing 
Service Bulletin 747-54-2118, dated July 25, 1986, until the 
modification of the nacelle strut and wing structure is accomplished 
in accordance with Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994.

    Note 3: These inspections of the fastener holes are required by 
AD 87-04-13 R1, amendment 39-5546, at 4,000-landing intervals. 
Accomplishment of the inspections of the fastener holes, as required 
by this paragraph at 1,000-landing intervals, constitutes compliance 
with paragraph A. of AD 87-04-13 R1.

    (iii) For airplanes on which all of the modifications described 
in the service bulletins referenced by paragraph I.D., 
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, have been accomplished; except that 
rework of the midspar fitting lugs or spring beam aft lugs was 
accomplished in accordance with Boeing Alert Service Bulletin 747-
54A2152, dated December 23, 1992, or Revision 1, dated July 15, 
1993, instead of Revision 2, dated September 16, 1993:
    (A) Within 56 months after the effective date of this AD, 
accomplish the modification of the nacelle strut and wing structure 
and perform the inspections of the adjacent structure that has not 
been replaced by the modification.
    (B) Prior to the accumulation of 2,500 landings or 3 years since 
rework of the lugs, whichever occurs earlier, perform an ultrasonic 
inspection to detect cracking of the inboard and outboard midspar 
fitting lugs or spring beam aft lugs of each strut, in accordance 
with Boeing Alert Service Bulletin 747-54A2152, Revision 2, dated 
September 16, 1993. Repeat this inspection thereafter as required by 
AD 93-17-07.

    Note 4: This ultrasonic inspection is required by AD 93-17-07, 
amendment 39-8678, to be performed prior to the accumulation of 
5,000 landings or 5 years since accomplishment of the rework of the 
lugs, whichever occurs earlier, in accordance with Boeing Alert 
Service Bulletin 747-54A2152, dated December 23, 1992, or Revision 
1, dated July 15, 1993. Repetitive inspections are required by that 
AD at intervals not to exceed 500 landings for inboard struts and 
1,000 landings for outboard struts. Since the issuance of that AD, 
the FAA has approved Revision 2 of Boeing Alert Service Bulletin 
747-54A2152, dated September 16, 1993, as an alternative method of 
compliance for accomplishment of these ultrasonic inspections and 
rework of the lugs. Revision 2 of the alert service bulletin 
recommends that lugs that have been reworked in accordance with the 
original issue or Revision 1 of the alert service bulletin be 
inspected prior to the accumulation of 2,500 landings or 3 years 
since accomplishment of the rework of the lugs, whichever occurs 
earlier. Therefore, accomplishment of ultrasonic inspections prior 
to the accumulation of 2,500 landings or 3 years since 
accomplishment of rework of the lugs, whichever occurs earlier, and 
thereafter as required by AD 93-17-07, constitutes compliance with 
paragraph (e)(2)(i)(A) of AD 93-17-07.
    (iv) For airplanes on which all of the modifications described 
in the service bulletins referenced by paragraph I.D., 
``Compliance,'' on page 17 of Boeing Alert Service Bulletin 747-
54A2152, dated November 3, 1994, have been accomplished; except that 
rework of the midspar fitting lugs or spring beam aft lugs was 
accomplished in accordance with the Boeing Alert Service Bulletin 
747-54A2152, dated December 23, 1992, or Revision 1, dated July 15, 
1993, instead of Revision 2, dated September 16, 1993; and excluding 
the modification described in Boeing Service Bulletin 747-54-2118, 
dated July 25, 1986:
    (A) Within 56 months after the effective date of this AD, 
accomplish the modification of the nacelle strut and wing structure 
and perform the inspections of the adjacent structure that has not 
been replaced by the modification.
    (B) Repeat the ultrasonic inspections to detect cracking of the 
aft-most two fastener holes in both strut midspar fittings on the 
inboard and outboard nacelle struts, as required by AD 87-04-13 R1, 
at intervals not to exceed 1,000 landings, in accordance with Boeing 
Service Bulletin 747-54-2118, dated July 25, 1986, until the 
modification of the nacelle strut and wing structure is accomplished 
in accordance with Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994.
    (C) Prior to the accumulation of 2,500 landings or 3 years since 
rework of the lugs, whichever occurs earlier, perform an ultrasonic 
inspection to detect cracking of the inboard and outboard midspar 
fitting lugs or spring beam aft lugs of each strut, and repeat the 
inspection thereafter as required by AD 93-17-07, until the 
modification of the nacelle strut and wing structure is accomplished 
in accordance with Boeing Alert Service Bulletin 747-54A2159, dated 
November 3, 1994.

    Note 5: Notes 3 and 4 are also applicable to this paragraph.

    (v) For all other airplanes not subject to the requirements of 
paragraph (a)(2)(i), (a)(2)(ii), (a)(2)(iii), or (a)(2)(iv) of this 
AD: Within 32 months after the effective date of this AD, accomplish 
the modification of the nacelle strut and wing structure and perform 
the inspections of the adjacent structure that has not been replaced 
by the modification.

    Note 6: The following table graphically illustrates the 
applicability and compliance times for accomplishing the 
modification of the nacelle strut and wing structure for as required 
by paragraph (a)(2) of this AD.

------------------------------------------------------------------------
                      Accomplishment of      Revision                   
    Paragraph         service bulletins       level      Compliance time
------------------------------------------------------------------------
(i)-.............  All in paragraph I.D.-  ...........  56 months.      
(ii).............  All except 747-54-2118  ...........  56 months.      
(iii)............  All except 747-54A2159            2  56 months.      
(iv).............  All except 747-54-2118            2  56 months.      
                    and 747-54A2159.                                    
(v)-.............  (\1\).................  ...........  32 months.      
------------------------------------------------------------------------
\1\Paragraph (a)(2)(v) of this AD is applicable to all airplanes, other 
  than those addressed in paragraphs (a)(2)(i), (a)(2)(ii), (a)(2)(iii),
  and (a)(2)(iv) of this AD. As such, these airplanes may have          
  accomplished some or none of the service bulletins listed in paragraph
  I.D. of Boeing Alert Service Bulletin 747-54A2159, dated November 3,  
  1994.                                                                 

    (b) Perform the inspections and checks specified in paragraph 
III, NOTES 8, 9, 10, and 11 of the Accomplishment Instructions on 
pages 149 and 150 of Boeing Alert Service Bulletin 747-54A2159, 
dated November 3, 1994, concurrently with the modification of the 
nacelle strut and wing structure required by paragraph (a) of this 
AD. Prior to further flight, correct any discrepancies found, in 
accordance with the alert service bulletin.
    (c) Accomplishment of the modification of the nacelle strut and 
wing structure in accordance with Boeing Alert Service Bulletin 747-
54A2159, dated November 3, 1994, constitutes terminating action for 
the inspections required by the following AD's:

----------------------------------------------------------------------------------------------------------------
          AD No.             Amendment No.      Federal Register citation             Date of publication       
----------------------------------------------------------------------------------------------------------------
94-17-17..................         39-9012  59 FR 44903......................  August 31, 1994.                 
94-10-05..................         39-8912  59 FR 25288......................  May 16, 1994.                    
93-17-07..................         39-8678  58 FR 45827......................  August 31, 1993.                 
93-03-14..................         39-8518  58 FR 14513......................  March 18, 1993.                  
92-24-51..................         39-8439  57 FR 60118......................  December 18, 1992.               
92-07-11..................         39-8207  57 FR 10415......................  March 26, 1992.                  
90-20-20..................         39-6725  55 FR 37859......................  September 14, 1990.              
90-17-18..................         39-6702  55 FR 33279......................  August 15, 1990.                 
89-07-15..................         39-6167  54 FR 11693......................  March 22, 1989.                  
87-04-13 R1...............         39-5546  52 FR 3421.......................  February 4, 1987.                
86-08-03..................         39-5289  51 FR 12836......................  April 16, 1986.                  
86-07-06..................         39-5270  51 FR 10821......................  March 31, 1986.                  
86-05-11..................         39-5255  51 FR 8479.......................  March 12, 1986.                  
86-23-01..................         39-5450  51 FR 37712......................  October 24, 1986.                
82-22-02..................         39-4476  47 FR 46842......................  October 21, 1982.                
80-08-02..................         39-3738  45 FR 24450......................  April 10, 1980.                  
79-17-07..................         39-3533  44 FR 50033......................  August 27, 1979.                 
----------------------------------------------------------------------------------------------------------------

    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle ACO. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane 
Directorate.

    Note 7: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on December 15, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-31328 Filed 12-20-94; 8:45 am]
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