[Federal Register Volume 65, Number 194 (Thursday, October 5, 2000)]
[Proposed Rules]
[Pages 59381-59383]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-25534]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

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.

========================================================================


Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / 
Proposed Rules

[[Page 59381]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-205-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-200, -200C, -300, and 
-400 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to revise an existing airworthiness 
directive (AD), applicable to certain Boeing Model 737-200, -200C, 
-300, and -400 series airplanes, that currently requires repetitive 
visual and high frequency eddy current (HFEC) inspections to detect 
cracking of the corners of the door frame and the cross beams of the 
aft cargo door, and corrective actions, if necessary. That amendment 
also mandates accomplishment of a modification to the aft cargo door, 
which would terminate the repetitive inspection requirements. This 
action would revise the compliance time of the terminating action. The 
actions specified by this proposal are intended to prevent fatigue 
cracking of the corners of the doorframe and the crossbeams of the aft 
cargo door, which could result in rapid depressurization of the 
airplane.

DATES: Comments must be received by November 20, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-205-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. Comments may also be sent via the Internet using the 
following address: <a href="/cdn-cgi/l/email-protection#4871652926256526383a252b2725252d263c082e2929662f273e"><span class="__cf_email__" data-cfemail="86bfabe7e8ebabe8f6f4ebe5e9ebebe3e8f2c6e0e7e7a8e1e9f0">[email protected]</span></a>. Comments sent via the 
Internet must contain ``Docket No. 2000-NM-205-AD'' in the subject line 
and need not be submitted in triplicate.
    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: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-2028; telephone (425) 
227-2557; 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.
    Submit comments using the following format:
    <bullet> Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    <bullet> For each issue, state what specific change to the proposed 
AD is being requested.
    <bullet> 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-205-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. 2000-NM-205-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 24, 2000, the FAA issued AD 2000-06-13, amendment 39-11654 
(65 FR 17583, April 4, 2000), applicable to certain Boeing Model 737-
200, -200C, -300, and -400 series airplanes, to require repetitive 
visual inspections and repetitive high frequency eddy current (HFEC) 
inspections to detect cracking of the corners of the door frame and the 
cross beams of the aft cargo door, and corrective actions, if 
necessary. That amendment also mandates accomplishment of a 
modification to the aft cargo door that terminates the repetitive 
inspection requirements. The actions specified by that AD are intended 
to prevent fatigue cracking of the corners of the door frame and the 
cross beams of the aft cargo door, which could result in rapid 
depressurization of the airplane.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has reviewed AD 2000-06-13 
and determined that the compliance times specified for the terminating 
action in paragraph (e) of that AD can be relaxed somewhat. Paragraph 
(e) of that AD states the compliance times as, ``prior to the 
accumulation of 12,000 total flight cycles, or within 4 years after the 
effective date of this AD, whichever occurs later.'' However, the FAA 
now has determined that the terminating action (modification of the aft 
cargo door) could be accomplished within ``12,000 flight cycles or 4 
years after the effective date of this AD, whichever occurs later.'' 
The revision to the compliance time will permit a reasonable and 
adequate amount of time for operators to accomplish the

[[Page 59382]]

terminating action, and will not adversely affect safety.

Editorial Explanation

    The FAA also has noted that in paragraphs (a)(2), (a)(3), (a)(4), 
and Note 2 of AD 2000-06-13, reference is made to performing certain 
actions in accordance with certain paragraphs (i.e., paragraph III.C., 
paragraph III.E., or paragraph III.F) of part 1 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-52A1079, Revision 6, 
dated November 18, 1999. While those specific paragraph references are 
correct for references to Revision 5 of the Boeing Alert Service 
Bulletin, they are not the correct paragraph references of Revision 6 
of the alert service bulletin. However, the correct reference section 
for both Revision 5 and Revision 6 is still in part 1 of the 
Accomplishment Instructions. Therefore, the FAA has deleted the 
references to specific paragraphs of part 1 of the Accomplishment 
Instructions of the alert service bulletin and retained reference only 
to part 1. Specifying that the actions must be accomplished in 
accordance with ``Part 1 of the Accomplishment Instructions'' of either 
revision will clarify and correct the appropriate references.

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 revise AD 2000-06-13 to continue to require 
repetitive visual and HFEC inspections to detect cracking of the 
corners of the door frame and the cross beams of the aft cargo door, 
and corrective actions, if necessary. This proposal also would relieve 
the existing compliance time for the terminating action required by AD 
2000-06-13 to modify the aft cargo door.

Cost Impact

    There are approximately 1,636 Model 737 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 707 
airplanes of U.S. registry would be affected by this AD.
    The detailed visual inspections that currently are required by AD 
2000-06-13, and retained in this AD, would take approximately 2 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 inspections on U.S. operators is estimated to be $84,840, or 
$120 per airplane, per inspection cycle.
    The high frequency eddy current inspections that would be required 
by this proposal would take approximately 4 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 proposed inspections on U.S. 
operators is estimated to be $169,680, or $240 per airplane, per 
inspection cycle.
    The modification proposed in this action would take approximately 
144 work hours per airplane to accomplish, at an average labor rate of 
$60 per work hour. Required parts would cost approximately $4,530 per 
airplane. Based on these figures, the estimated cost impact of the 
proposed modification on U.S. operators is estimated to be $9,311,190, 
or $13,170 per airplane.
    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 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.
    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 39-11654 (65 FR 
17583, April 4, 2000), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2000-NM-205-AD. Revises AD 2000-06-13, Amendment 39-
11654.

    Applicability: The following airplane models, certificated in 
any category.
    <bullet> Model 737-200 and -200C series airplanes, line numbers 
6 through 873 inclusive;
    <bullet> Model 737-200, -200C, -300, and -400 series airplanes; 
line numbers 874 through 1642 inclusive; equipped with an aft cargo 
door having Boeing part number (P/N) 65-47952-1 or P/N 65-47952-524; 
excluding:
    1. Those airplanes on which that door has been modified in 
accordance with Boeing Service Bulletin 737-52-1079; or
    2. Those airplanes on which the door assembly having P/N 65-
47952-524 includes four straps (P/N's 65-47952-139, 65-47952-140, 
65-47952-141, and 65-47952-142) and a thicker lower cross beam web 
(P/N 65-47952-157).

    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 (f)(1) 
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 fatigue cracking of the corners of the doorframe and 
the cross beams of the aft cargo door, which could result in rapid 
depressurization of the airplane, accomplish the following:

Restatement of the Requirements of AD 98-25-06

Inspections and Corrective Actions

    (a) Within 90 days or 700 flight cycles after December 24, 1998 
(the effective date of AD

[[Page 59383]]

98-25-06, amendment 39-10931), whichever occurs later, perform an 
internal detailed visual inspection to detect cracking of the 
corners of the door frame and the cross beams of the aft cargo door, 
in accordance with Boeing Service Bulletin 737-52-1079, Revision 5, 
dated May 16, 1996, or Boeing Alert Service Bulletin 737-52A1079, 
Revision 6, dated November 18, 1999.
    (1) If no cracking is detected, accomplish the requirements of 
either paragraph (a)(1)(i) or (a)(1)(ii) of this AD.
    (i) Repeat the internal visual inspection thereafter at 
intervals not to exceed 4,500 flight cycles. Or
    (ii) Prior to further flight, modify the corners of the 
doorframe and the crossbeams of the aft cargo door in accordance 
with the service bulletin. Accomplishment of such modification 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a)(1)(i) of this AD.
    (2) If any cracking is detected in the upper or lower cross 
beams, prior to further flight, modify the cracked beam in 
accordance with Part I of the Accomplishment Instructions of the 
service bulletin. Accomplishment of such modification constitutes 
terminating action for the repetitive inspection requirements of 
paragraph (a)(1)(i) of this AD for the repaired beam.
    (3) If any cracking is detected in the forward or aft upper door 
frame, prior to further flight, repair the frame and modify the 
corners of the door frame of the aft cargo door, in accordance with 
Part I of the Accomplishment Instructions of the service bulletin, 
except as provided by paragraph (b) of this AD. Accomplishment of 
such modification constitutes terminating action for the repetitive 
inspection requirements of paragraph (a)(1)(i) of this AD for the 
upper doorframe.

    Note 2: Cracks of the forward or aft upper door frame, 
regardless of length, must be repaired prior to further flight in 
accordance with Part I of the Accomplishment Instructions of the 
service bulletin.

    (4) If any cracking is detected in the forward or aft lower door 
frame, prior to further flight, replace the damaged frame with a new 
frame, and modify the corners of the door frame of the aft cargo 
door, in accordance with Part I of the Accomplishment Instructions 
of the service bulletin. Accomplishment of such modification 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a)(1)(i) of this AD for the lower 
doorframe.
    (b) Where Boeing Service Bulletin 737-52-1079, Revision 5, dated 
May 16, 1996, or Boeing Alert Service Bulletin, 737-52A1079, 
Revision 6, dated November 18, 1999, specifies that certain repairs 
are to be accomplished in accordance with instructions received from 
Boeing, this AD requires that, prior to further flight, such repairs 
be accomplished in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA.

New Requirements of This AD

Inspections and Corrective Actions

    (c) If any cracking of the outer chord of the upper or lower 
cross beams of the aft cargo door is detected as a result of any 
inspection required by paragraph (a) of this AD, prior to further 
flight, repair in accordance with a method approved by the Manager, 
Seattle ACO; Boeing Alert Service Bulletin, 737-52A1079, Revision 6, 
dated November 18, 1999; 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.
    (d) Within 4,500 flight cycles or one year after the effective 
date of this AD, whichever occurs later: Perform a high frequency 
eddy current inspection (HFEC) to detect cracking of the four 
corners of the door frame of the aft cargo door, in accordance with 
the procedures specified in Boeing 737 Nondestructive Test Manual, 
Part 6, Chapter 51-00-00 (Figure 4 or Figure 23), or Boeing Alert 
Service Bulletin, 737-52A1079, Revision 6, dated November 18, 1999;
    (1) If no cracking of the corners of the doorframe of the aft 
cargo door is detected, repeat the HFEC inspections thereafter at 
intervals not to exceed 4,500 flight cycles until accomplishment of 
the modification specified in paragraph (e) of this AD.
    (2) If any cracking of the corners of the door frame of the aft 
cargo door is detected, prior to further flight, replace the damaged 
frame with a new frame, and modify the four corners of the door 
frame, in accordance with Parts II and III of the Accomplishment 
Instructions of Boeing Service Bulletin 737-52-1079, Revision 5, 
dated May 16, 1996, or Boeing Alert Service Bulletin 737-52A1079, 
Revision 6, dated November 18, 1999. Accomplishment of such 
modification constitutes terminating action for the repetitive 
inspection requirements of paragraph (d)(1) of this AD for that 
doorframe.

Terminating Action

    (e) Within 4 years or 12,000 flight cycles after the effective 
date of this AD, whichever occurs later: Modify the four corners of 
the door frame and the cross beams of the aft cargo door, in 
accordance with Part II of the Accomplishment Instructions of Boeing 
Service Bulletin 737-52-1079, Revision 5, dated May 16, 1996, or 
Boeing Alert Service Bulletin 737-52A1079, Revision 6, dated 
November 18, 1999. Accomplishment of that modification constitutes 
terminating action for the repetitive inspection requirements of 
this AD.

    Note 3: Accomplishment of the modification required by paragraph 
(a) of AD 90-06-02, amendment 39-6489, is considered acceptable for 
compliance with paragraph (e) of this AD.


    Note 4: Modification of the corners of the door frame and the 
cross beams of the aft cargo door accomplished prior to the 
effective date of this AD in accordance with Boeing Service Bulletin 
737-52-1079, dated December 16, 1983; Revision 1, dated December 15, 
1988; Revision 2, dated July 20, 1989; Revision 3, dated May 17, 
1990; Revision 4, dated February 21, 1991; is considered acceptable 
for compliance with paragraph (e) of this AD.

Alternative Methods of Compliance

    (f)(1) 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 98-25-06, amendment 39-10931, are approved as 
alternative methods of compliance with this AD.

    Note 5: 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

    (g) Special flight permits may be issued in accordance with 
Secs. 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 September 29, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-25534 Filed 10-4-00; 8:45 am]
BILLING CODE 4910-13-P


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