[Federal Register Volume 68, Number 142 (Thursday, July 24, 2003)]
[Proposed Rules]
[Pages 43688-43690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-18788]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NM-278-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200C and -200F Series 
Airplanes

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 747-200C and 
-200F series airplanes. This proposal would require repetitive 
inspections to find fatigue cracking in the upper chord of the upper 
deck floor beams, and repair if necessary. For certain airplanes, this 
proposal would also provide for an optional repair/modification, which 
would extend certain repetitive inspection intervals. This action is 
necessary to find and fix cracking in certain upper deck floor beams. 
Such cracking could extend and sever floor beams adjacent to the body 
frame and could result in rapid decompression and consequent loss of 
controllability of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by September 8, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2001-NM-278-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2001-NM-278-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 or 2000 or 
ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, PO 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) 917-6434; fax (425) 917-6590.

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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a

[[Page 43689]]

request to change the service bulletin reference as two separate 
issues.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NM-278-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. 2001-NM-278-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report of fatigue cracking of the station 
(STA) 340 upper deck floor beam on a Boeing Model 747-200F series 
airplane. The upper chord and web were completely severed by a crack 
which originated at a floor panel attachment fastener hole. A previous 
blend-out repair for corrosion was found at the crack location, and 
corrosion pitting was found in the fastener hole. Additionally, a 0.3-
inch-long crack was found at an adjacent fastener hole. On certain 
Boeing Model 747-200C and -200F series airplanes, the upper chords of 
the floor beams at body station (BS) 340 through BS 440, and BS 500 
through BS 520, are made from 7075 aluminum, which is more susceptible 
to fatigue cracking. BS 460 and BS 480 upper deck floor beams on these 
models are made from 2024 aluminum, which is known to be more durable 
than 7075 aluminum against fatigue. Cracking of the upper deck floor 
beam, if not corrected, could extend and sever floor beams adjacent to 
the body frame, which could result in rapid decompression and 
consequent loss of controllability of the airplane.

Other Relevant Rulemaking

    On February 22, 2000, we issued AD 2000-04-17, amendment 39-11600 
(65 FR 10695, February 29, 2000). That AD applies to certain Boeing 
Model 747-100, -200, and -300 series airplanes, and requires repetitive 
inspections to detect fatigue cracking in the upper deck floor beams 
located at certain body stations, and repair if necessary.

Explanation of Relevant Service Information

    We have reviewed and approved Boeing Alert Service Bulletin 747-
53A2439, dated July 5, 2001, which describes procedures for repetitive 
inspections to find fatigue cracking in the upper chord of the upper 
deck floor beams, and repair if necessary, as follows:
    [sbull] If access is gained from above, the procedures specify an 
open-hole high frequency eddy current (HFEC) inspection of the 
attachment fastener holes of the floor panel for cracks in the upper 
chord.
    [sbull] If access is gained from below, the procedures specify 
modification of the clip nuts of the attachment fastener holes of the 
floor panel, and surface HFEC inspections of the forward and aft 
horizontal flanges of the floor beam upper chord for cracks.
    [sbull] If any crack is found, the procedures specify 
accomplishment of the repair in the service bulletin or contacting 
Boeing for repair instruction, and repetitive inspections of the 
repaired area. If no crack is found, repeat the applicable inspection.
    The service bulletin also describes procedures for an optional 
repair/modification, which would extend certain repetitive inspection 
intervals.
    Accomplishment of the actions specified in the service bulletin is 
intended to adequately address the identified unsafe condition.

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 require accomplishment of the actions specified in 
the service bulletin described previously, except as discussed below.

Difference Between the Alert Service Bulletin and This Proposed AD

    Although the alert service bulletin specifies that the manufacturer 
may be contacted for disposition of certain repair conditions, this 
proposed AD would require the repair of those conditions to be 
accomplished in accordance with a method approved by the FAA, or in 
accordance with data meeting the type certification basis of the 
airplane approved by a Boeing Company Designated Engineering 
Representative who has been authorized by the FAA to make such 
findings.

Changes to 14 CFR Part 39/Effect on the Proposed AD

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives system. The regulation now includes material that relates to 
altered products, special flight permits, and alternative methods of 
compliance. Because we have now included this material in part 39, we 
no longer need to include it in each individual AD; however, this AD 
identifies the office authorized to approve alternative methods of 
compliance.

Cost Impact

    There are approximately 78 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 21 airplanes of U.S. registry 
would be affected by this proposed AD, that it would take approximately 
30 work hours per airplane to accomplish the proposed inspections, and 
that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the inspections proposed by this AD on U.S. 
operators is estimated to be $37,800, or $1,800 per airplane, per 
inspection cycle.
    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 proposed AD were not adopted. The cost impact 
figures discussed in AD rulemaking actions represent only the time 
necessary to perform the specific actions actually required by the AD. 
These figures typically do not include incidental costs, such as the 
time required to gain access and close up, planning time, or time 
necessitated by other administrative actions.

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.

[[Page 43690]]

    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 adding the following new 
airworthiness directive:

Boeing: Docket 2001-NM-278-AD.

    Applicability: Model 747-200C and -200F series airplanes, as 
listed in Boeing Alert Service Bulletin 747-53A2439, dated July 5, 
2001; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix cracking in certain upper deck floor beams, 
which could extend and sever floor beams adjacent to the body frame 
and could result in rapid decompression and consequent loss of 
controllability of the airplane, accomplish the following:

Inspections and Repair

    (a) Before the accumulation of 22,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever is later: Do the applicable inspection to find fatigue 
cracking in the upper chord of the upper deck floor beams as 
specified in Part 1 (Open-Hole High Frequency Eddy Current (HFEC) 
Inspection Method) or Part 2 (Surface HFEC Inspection Method) of the 
Work Instructions of Boeing Alert Service Bulletin 747-53A2439, 
dated July 5, 2001. Do the inspections per the service bulletin.
    (1) If any crack is found, before further flight, repair per 
Part 3 (Repair) of the Work Instructions of the service bulletin; 
except where the service bulletin specifies to contact Boeing for 
appropriate action, before further flight, repair according to a 
method approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA; or according to data meeting the type 
certification basis of the airplane approved by a Boeing Company 
Designated Engineering Representative (DER) who has been authorized 
by the Manager, Seattle ACO, to make such findings. For a repair 
method to be approved by the Manager, Seattle ACO, as required by 
this paragraph, the Manager's approval letter must specifically 
reference this AD. Do the applicable inspection of the repaired area 
per Part 1 of the service bulletin at the applicable time per Part 3 
of the service bulletin. Repeat the applicable inspection at the 
applicable interval per Figure 1 of the service bulletin.
    (2) If no crack is found, repeat the applicable inspection per 
paragraph (a) of this AD within the applicable interval per Figure 1 
of the service bulletin. As an option, accomplishment of paragraph 
(b)(1) or (b)(2) of this AD, before further flight, extends the 
threshold for the initiation of the repetitive inspections required 
by this paragraph.

Optional Repair/Modification

    (b) For airplanes on which the inspection required by paragraph 
(a) of this AD is done per Part 1 of the Work Instructions of Boeing 
Alert Service Bulletin 747-53A2439, dated July 5, 2001; and on which 
no cracking is found: Accomplishment of the actions specified in 
either paragraph (b)(1) or (b)(2) of this AD extends the threshold 
for the initiation of the repetitive inspections required by 
paragraph (a)(2) of this AD.
    (1) Do the repair per Part 3 of the service bulletin. At the 
applicable time specified in Table 1 of Part 3 of the service 
bulletin, do the inspection of the repaired area per Part 1 of the 
service bulletin. Repeat the inspection thereafter within the 
applicable interval per Figure 1 of the service bulletin.
    (2) Do the modification of the attachment hole of the floor 
panel per Figure 5 of the service bulletin. Within 10,000 flight 
cycles after accomplishment of the modification, do the inspection 
of the modified area per Part 1 of the service bulletin. Repeat the 
inspection thereafter within the applicable interval per Figure 1 of 
the service bulletin.

Adjustments to Compliance Time: Cabin Differential Pressure

    (c) For the purposes of calculating the compliance threshold and 
repetitive interval for the actions required by paragraph (a) of 
this AD: The number of flight cycles in which cabin differential 
pressure is at 2.0 pounds per square inch (psi) or less need not be 
counted when determining the number of flight cycles that have 
occurred on the airplane, provided that flight cycles with momentary 
spikes in cabin differential pressure above 2.0 psi are included as 
full pressure cycles. For this provision to apply, all cabin 
pressure records must be maintained for each airplane. No fleet-
averaging of cabin pressure is allowed.

Alternative Methods of Compliance

    (d)(1) In accordance with 14 CFR 39.19, the Manager, Seattle 
ACO, is authorized to approve alternative methods of compliance 
(AMOCs) for this AD.
    (2) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by a 
Boeing Company DER who has been authorized by the Manager, Seattle 
ACO, to make such findings.

    Issued in Renton, Washington, on July 18, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-18788 Filed 7-23-03; 8:45 am]
BILLING CODE 4910-13-P