[Federal Register Volume 65, Number 35 (Tuesday, February 22, 2000)]
[Proposed Rules]
[Pages 8667-8669]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-4121]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 65, No. 35 / Tuesday, February 22, 2000 / 
Proposed Rules  

[[Page 8667]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-88-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, -200, -300, 
747SR, and 747SP Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747-
100, -200, -300, 747SR, and 747SP series airplanes, that currently 
requires a one-time inspection to detect cracking of the longeron 
splice fittings at stringer 11, on the left and right sides at body 
station 2598, and replacement of any cracked fitting with a new 
fitting. This action would reduce the compliance time for 
accomplishment of the currently required inspection and add a new 
requirement for repetitive inspections. This proposal is prompted by 
reports that fatigue cracking was found on longeron splice fittings. 
The actions specified by the proposed AD are intended to detect and 
correct such fatigue cracking, which could result in reduced 
controllability of the horizontal stabilizer.

DATES: Comments must be received by April 7, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-88-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: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1153; fax (425) 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 97-NM-88-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-114, Attention: Rules 
Docket No. 97-NM-88-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On December 19, 1997, the FAA issued AD 97-26-21, amendment 39-
10264 (62 FR 67550, December 29, 1997), applicable to certain Boeing 
Model 747-100, -200, -300, 747SR, and 747SP series airplanes. That AD 
requires a one-time inspection to detect cracking of the longeron 
splice fittings at stringer 11, on the left and right sides at body 
station 2598, and replacement of any cracked fitting with a new 
fitting. That action was prompted by reports that fatigue cracking was 
found on longeron splice fittings. The requirements of that AD are 
intended to detect and correct such fatigue cracking, which could 
result in reduced controllability of the horizontal stabilizer.
    In the preamble to AD 97-26-21, the FAA indicated that the actions 
required by that AD were considered ``interim action'' and that further 
rulemaking action to propose repetitive inspections for all affected 
airplanes was being considered. The FAA now has determined that further 
rulemaking action is indeed necessary, and this proposed AD follows 
from that determination.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 747-
53A2410, Revision 3, dated March 12, 1998, including Addendum. That 
service bulletin describes procedures for repetitive detailed visual 
inspections to detect cracking of the longeron splice fittings at 
stringer 11, on the left and right sides at body station 2598, and 
replacement of any cracked fitting with a new fitting. The procedures 
described in that service bulletin are essentially similar to those 
described in Boeing Alert Service Bulletin 747-53A2410, Revision 2, 
dated October 30, 1997, which was referenced in AD 97-26-21 as the 
appropriate source of service information. Among other things, Revision 
3 of the service bulletin includes a new table that clarifies what 
fastener kits are necessary for each splice fitting replacement. 
Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.

[[Page 8668]]

Explanation of Requirements of Proposed Rule

    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 supersede AD 97-26-21 to continue to require an 
inspection to detect cracking of the longeron splice fittings at 
stringer 11, on the left and right sides at body station 2598, and 
replacement of any cracked fitting with a new fitting. The proposed AD 
would reduce the compliance time for accomplishment of the currently 
required inspection and add a new requirement for repetitive 
inspections. The actions would be required to be accomplished in 
accordance with the service bulletin described previously, except as 
discussed below.

Differences Between Service Bulletin and Proposed AD

    The logic diagram in the service bulletin recommends a grace period 
of 500 flight cycles or 2,000 flight hours (whichever occurs first) for 
airplanes that have accumulated more than 22,000 total flight cycles or 
78,000 total flight hours. Operators should note that this proposed AD 
does not provide a grace period for these airplanes. This proposed AD 
would require accomplishment of the initial inspection no later than 
the accumulation of 22,000 total flight cycles or 78,000 total flight 
hours, whichever occurs first. In AD 97-26-21, the FAA provides a grace 
period of 90 days after January 13, 1998 (the effective date of AD 97-
26-21), in place of the grace period of 500 flight cycles or 2,000 
flight hours recommended in the service bulletin. Because one of the 
purposes of the proposed AD is to reduce the initial compliance time 
for the inspection, the FAA finds that it would be inappropriate to 
allow airplanes that are approaching the inspection threshold of 22,000 
total flight cycles or 78,000 total flight hours, i.e., the time when 
they would be required to accomplish the inspection required by AD 97-
26-21, to continue to fly for additional time beyond the threshold 
specified in that AD. Also, since no additional airplanes would be 
added to the applicability of this proposed AD, all airplanes that 
would be subject to this proposed AD are currently subject to AD 97-26-
21, and the grace period provided in AD 97-26-21 has already passed, 
this proposed AD does not restate that grace period.

Explanation of Compliance Time

    The FAA finds that the service bulletin is not clear about the 
initial inspection threshold for airplanes with fewer than 17,000 total 
flight cycles or 63,000 total flight hours. Boeing has advised the FAA 
that it intended to provide an initial inspection threshold of 17,000 
total flight cycles or 63,000 total flight hours (whichever occurs 
first), with a grace period of 1,800 flight cycles or 7,000 flight 
hours for airplanes that have already exceeded these thresholds upon 
receipt of the service bulletin. Therefore, this proposed AD provides 
compliance times that are consistent with Boeing's intent.

Cost Impact

    There are approximately 685 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 99 airplanes of U.S. registry 
would be affected by this proposed AD.
    The inspection that is currently required by AD 97-26-21 takes 
approximately 32 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required actions on U.S. operators is estimated 
to be $190,080, or $1,920 per airplane.
    The proposed AD would require the same inspection currently 
required by AD 97-26-21 to be accomplished repetitively. Therefore, the 
cost impact of the proposed requirements of this AD on U.S. operators 
is estimated to be $190,080, or $1,920 per airplane, per inspection 
cycle.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
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 proposed herein would not have a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-10264 (62 FR 
67550, December 29, 1997), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing:   Docket 97-NM-88-AD. Supersedes AD 97-26-21, Amendment 39-
10264.

    Applicability: Model 747-100, 747-200, 747-300, 747SR, and 747SP 
series airplanes; having line positions 201 through 886 inclusive; 
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 (d) 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 detect and correct fatigue cracking of the longeron splice 
fittings at stringer 11, which could result in reduced 
controllability of the horizontal stabilizer, accomplish the 
following:

Initial Inspection

    (a) Perform a one-time detailed visual inspection to detect 
cracking of the longeron fittings at stringer 11, on the left and 
right sides at body station 2598, at the time specified in paragraph 
(a)(1) or (a)(2) of this AD, as applicable, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2410, Revision 2,

[[Page 8669]]

dated October 30, 1997, including Addendum; or Boeing Service 
Bulletin 747-53A2410, Revision 3, dated March 12, 1998, including 
Addendum. After the effective date of this AD, only Revision 3 shall 
be used.
    (1) For airplanes that have accumulated fewer than 17,000 total 
flight cycles or 63,000 total flight hours as of the effective date 
of this AD: Inspect at the later of the times specified in paragraph 
(a)(1)(i) or (a)(1)(ii) of this AD.
    (i) Prior to the accumulation of 17,000 total flight cycles or 
63,000 total flight hours, whichever occurs first.
    (ii) Within 1,800 flight cycles or 7,000 flight hours after the 
effective date of this AD, whichever occurs first.
    (2) For airplanes that have accumulated 17,000 total flight 
cycles or more, or 63,000 total flight hours or more, as of the 
effective date of this AD: Inspect at the earlier of the times 
specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
    (i) Prior to the accumulation of 22,000 total flight cycles or 
78,000 total flight hours, whichever occurs first.
    (ii) Within 1,800 flight cycles or 7,000 flight hours after the 
effective date of this AD, whichever occurs first.

    Note 2:
    Where there are differences between the AD and the service 
bulletin, the AD prevails.


    Note 3:
    For the purposes of this AD, a detailed visual inspection is 
defined as: ``An intensive visual examination of a specific structural 
area, system, installation, or assembly to detect damage, failure, or 
irregularity. Available lighting is normally supplemented with a direct 
source of good lighting at intensity deemed appropriate by the 
inspector. Inspection aids such as mirror, magnifying lenses, etc., may 
be used. Surface cleaning and elaborate access procedures may be 
required.''

Repetitive Inspections

    (b) If no crack is found during the inspection required by 
paragraph (a) of this AD, repeat the inspection one time at the 
later of the times specified in paragraphs (b)(1) and (b)(2) of this 
AD, and thereafter at intervals not to exceed 3,000 flight cycles or 
18,000 flight hours, whichever occurs first.
    (1) Within 3,000 flight cycles or 18,000 flight hours after 
accomplishment of the most recent inspection, whichever occurs 
first.
    (2) Within 1,800 flight cycles or 7,000 flight hours after the 
effective date of this AD, whichever occurs first.

Replacement and Repetitive Inspections

    (c) If any crack is found during any inspection required by 
paragraph (a) or (b) of this AD: Prior to further flight, replace 
the cracked fitting with a new fitting, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2410, Revision 2, dated October 30, 1997, including Addendum; or 
Boeing Service Bulletin 747-53A2410, Revision 3, dated March 12, 
1998, including Addendum. After the effective date of this AD, only 
Revision 3 shall be used. Then, repeat the inspection specified in 
paragraph (a) of this AD at the later of the times specified in 
paragraphs (c)(1) and (c)(2) of this AD, and thereafter at intervals 
not to exceed 3,000 flight cycles or 18,000 flight hours, whichever 
occurs first.
    (1) Within 17,000 flight cycles or 63,000 flight hours after 
replacement, whichever occurs first.
    (2) Within 1,800 flight cycles or 7,000 flight hours after the 
effective date of this AD, whichever occurs first.

Alternative Methods of Compliance

    (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 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 4:
    Information concerning the existence of approved alternative 
methods of compliance with this AD, if any, may be obtained from the 
Seattle ACO.

Special Flight Permits

    (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 February 15, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-4121 Filed 2-18-00; 8:45 am]
BILLING CODE 4910-13-P