[Federal Register Volume 64, Number 66 (Wednesday, April 7, 1999)]
[Rules and Regulations]
[Pages 16810-16812]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8309]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-326-AD; Amendment 39-11105; AD 99-08-01]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747 series airplanes, that requires 
repetitive detailed visual inspections for corrosion, and repetitive 
high frequency eddy current (HFEC) inspections for cracks, of the upper 
link assembly on the number 2 and number 3 engine struts, and 
corrective actions, if necessary. This amendment is prompted by reports 
of corrosion and cracks located at the four fasteners that attach to 
the aft end to the upper link assembly on the number 2 and number 3 
engine struts. The actions specified by this AD are intended to prevent 
failure of the upper link due to cracking or corrosion, subsequent 
damage to other strut support structure, and in-flight separation of an 
engine from the airplane.

DATES: Effective May 12, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 12, 1999.

ADDRESSES: 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 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. Anderson, Aerospace 
Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425) 
227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD)

[[Page 16811]]

that is applicable to certain Boeing Model 747 series airplanes was 
published in the Federal Register on April 9, 1998 (63 FR 17344). That 
action proposed to require repetitive detailed visual inspections for 
corrosion, and repetitive high frequency eddy current (HFEC) 
inspections for cracks, of the upper link assembly on the number 2 and 
number 3 engine struts, and corrective actions, if necessary.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Support for Proposed Rule

    Two commenters support the proposed rule.

Request to Revise Compliance Time for the Initial Inspections of 
Certain Airplanes

    One commenter, Boeing, notes that Chapter 54-00-01 of the Overhaul 
Manual (OHM) does not provide repair instructions other than 
instructions for replacement of the upper link aft fitting or the upper 
link tube. For airplanes with upper link assemblies that were 
overhauled in accordance with Chapter 54-00-01 of the OHM, and on which 
the four aft end attach bolts were installed with sealant, FLAG NOTE 1 
of Figure 1 of Boeing Alert Service Bulletin 747-54A2187, dated May 22, 
1997 (which is referenced in the proposed AD as the appropriate source 
of service information for accomplishment of the required inspections) 
recommends that the initial inspection be accomplished within 6,000 
flight cycles or 8 years after the upper link assembly was overhauled.
    From this comment, the FAA infers that the commenter is pointing 
out an error in the referenced alert service bulletin and is requesting 
that all affected airplanes be inspected at the later of the times 
specified in paragraphs (a)(2)(i) and (a)(2)(ii) of the proposed AD. 
The FAA concurs. Because the instructions for the subject overhaul are 
not available, the FAA has extended the compliance time for those 
affected airplanes to coincide with the compliance time for all other 
affected airplanes. The FAA has revised the final rule accordingly.

Request to Delete Note 2

    One commenter requests that FAA delete Note 2 of the notice of 
proposed rulemaking (NPRM). The commenter points out that Note 2 
removes the operator's ``equivalent procedure'' allowance specified in 
Boeing Alert Service Bulletin 747-54A2187. The commenter states that 
most airlines have FAA-approved procedures that are part of the 
maintenance program. These procedures are developed because each 
manufacturer has a slightly different procedure for commonly used 
processes. If operators are forced to use each manufacturer's specific 
procedure (i.e., Boeing 747 Airplane Maintenance Manual), as specified 
in Note 2, an undue burden would be placed on the operators. In 
addition, the FAA's Seattle Aircraft Certification Office (ACO) would 
receive numerous requests for approval of an alternative method of 
compliance (AMOC), which could delay implementation of the AD and 
significantly affect operators' ability to respond to AD's that have 
short compliance times.
    The FAA concurs with the commenter's request to delete Note 2 of 
the NPRM. The FAA has reconsidered its position, as was stated under 
the heading ``Differences Between Proposed Rule and Alert Service 
Bulletin.'' The FAA has determined that procedures ``equivalent'' to 
those procedures specified in the referenced alert service bulletin for 
removing or replacing the upper link that are employed by an operator 
will adequately address the identified unsafe condition and provide an 
acceptable level of safety. The FAA finds that, if an operator is 
required to remove or replace the upper link, those corrective actions 
may be accomplished in accordance with either the applicable chapter of 
the Boeing 747 Airplane Maintenance Manual (AMM) or an operator's 
``equivalent procedure,'' when specified in the referenced alert 
service bulletin. Therefore, the FAA has removed Note 2 of the NPRM 
from the final rule.

Request to Clarify the Term ``Certain Corrective Actions''

    One commenter requests that the FAA clarify whether the term 
``certain corrective actions,'' as described under the heading 
``Differences Between Proposed Rule and Alert Service Bulletin'' in the 
proposed AD, applies to repairs as well as removal and installation. 
The commenter states that the referenced alert service bulletin 
specifies that an operator's ``equivalent procedure'' may be used for 
removal or installation of the upper links and does not specify that an 
operator's ``equivalent procedure'' may be used for repairs of the 
upper links. In addition, the commenter points out that Note 2 of the 
NPRM states ``* * * and Boeing Alert Service Bulletin 747-54A2187, 
dated May 22, 1997, specifies that corrective actions may be 
accomplished in accordance with an operator's `equivalent procedure.'''
    The FAA finds that clarification is necessary. The term ``certain'' 
in that paragraph refers to some of the required corrective actions. 
The operator's ``equivalent procedure'' does not apply to the 
inspection specified in Figure 2 or the repair specified in Figure 3 of 
the alert service bulletin. The alert service bulletin specifies that 
``certain'' corrective actions (i.e., removing, installing, and 
replacing the upper link) may be accomplished in accordance with an 
operator's ``equivalent procedure.'' Therefore, the FAA finds that the 
term ``certain'' is correct in that paragraph. The FAA acknowledges 
that Note 2 of NPRM incorrectly reads ``corrective actions,'' rather 
than ``certain corrective actions.'' However, as discussed previously, 
Note 2 is not restated in the final rule, thus, no change to the final 
rule is necessary.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 567 Boeing Model 747 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 173 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 12 work hours per airplane to accomplish the 
required inspections, and that the average labor rate is $60 per work 
hour. Based on these figures, the cost impact of the AD on U.S. 
operators is estimated to be $124,560, or $720 per airplane, per 
inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the requirements of this AD 
action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

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,

[[Page 16812]]

it is determined that this final rule does not have sufficient 
federalism implications to warrant the preparation of a Federalism 
Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

99-08-01  Boeing: Amendment 39-11105. Docket 97-NM-326-AD.

    Applicability: Model 747 series airplanes, line positions 1 
through 886 inclusive; equipped with Pratt & Whitney JT9D-3 or -7, 
or General Electric CF6-45 or -50 engine struts; 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 request approval for an 
alternative method of compliance in accordance with paragraph (e) 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 upper link due to cracking or 
corrosion, subsequent damage to other strut support structure, and 
in-flight separation of an engine from the airplane, accomplish the 
following:
    (a) Perform a detailed visual inspection for corrosion, and a 
high frequency eddy current (HFEC) inspection for cracks, of the 
upper link assembly on the number 2 and number 3 engine struts, in 
accordance with Boeing Alert Service Bulletin 747-54A2187, dated May 
22, 1997, at the later of the times specified in paragraphs (a)(1) 
and (a)(2) of this AD.
    (1) Within 6,000 total flight cycles, or 8 years after the date 
of manufacture of the airplane, whichever occurs first.
    (2) Within 600 flight cycles, or 6 months after the effective 
date of this AD, whichever occurs first.
    (b) If no crack or corrosion is detected during any inspection 
required by paragraph (a) of this AD, repeat the inspections 
specified in paragraph (a) of this AD, thereafter, at intervals not 
to exceed 18 months.
    (c) If any crack or corrosion is detected during any inspection 
required by this AD, prior to further flight, accomplish either 
paragraph (c)(1) or (c)(2) of this AD, in accordance with Boeing 
Alert Service Bulletin 747-54A2187, dated May 22, 1997. Thereafter, 
repeat the inspections required by paragraph (a) of this AD, at 
intervals not to exceed 6,000 flight cycles or 8 years, whichever 
occurs first.
    (1) Repair the upper link within the limits specified in the 
alert service bulletin, in accordance with Part 2 of the 
Accomplishment Instructions of the alert service bulletin. (Complete 
corrosion and crack removal must be achieved within the limits 
specified in the alert service bulletin.) Or
    (2) Replace the upper link with a new upper link assembly, in 
accordance with Part 3 of the Accomplishment Instructions of the 
alert service bulletin.
    (d) Accomplishment of the modifications required in AD 95-13-07, 
amendment 39-9287 (for General Electric CF6-45 or -50 engine 
struts); or AD 95-10-16, amendment 39-9233 (for Pratt & Whitney 
JT9D-3 or -7 engine struts); constitutes terminating action for the 
requirements of this AD.
    (e) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) 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.
    (g) Except as provided by paragraph (d) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 747-
54A2187, dated May 22, 1997. 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.
    (h) This amendment becomes effective on May 12, 1999.

    Issued in Renton, Washington, on March 29, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-8309 Filed 4-6-99; 8:45 am]
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