[Federal Register Volume 68, Number 42 (Tuesday, March 4, 2003)]
[Proposed Rules]
[Pages 10188-10190]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-4990]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-219-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 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 all Boeing Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes, that currently 
requires repetitive inspections to find cracks, fractures, or corrosion 
of each carriage spindle of the left and right outboard mid-flaps; and 
corrective action, if necessary. This action would mandate the 
previously optional overhaul or replacement of the carriage spindles, 
which would end the repetitive inspections required by the existing AD. 
The actions specified by the proposed AD are intended to prevent severe 
flap asymmetry due to fractures of the carriage spindles on an outboard 
mid-flap, which could result in reduced control or loss of 
controllability of the airplane. This action is intended to address the 
identified unsafe condition.

DATES: Comments must be received by April 18, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2002-NM-219-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. 2002-NM-219-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 for Windows or 
ASCII text.
    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: Sue Lucier, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6438; 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 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 2002-NM-219-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. 2002-NM-219-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On October 22, 2002, the FAA issued AD 2002-22-05, amendment 39-
12929 (67 FR 66316, October 31, 2002), applicable to all Boeing Model 
737-100, -200, -200C, -300, -400, and -500 series airplanes, to require 
repetitive inspections to find cracks, fractures, or corrosion of each 
carriage spindle of the left and right outboard mid-flaps; and 
corrective action, if necessary. That action also provides for an 
optional action of overhaul or replacement of the carriage spindles, 
which would extend the repetitive inspection interval. The requirements 
of that AD are intended to prevent severe flap asymmetry due to 
fractures of the carriage spindles on an outboard mid-flap, which could 
result in reduced control or loss of controllability of the airplane.

Actions Since Issuance of Previous Rule

    In the preamble to AD 2002-22-05, we specified that the actions 
required by that AD were considered ``interim action'' and that we were 
considering requiring the optional overhaul or replacement of the 
carriage spindles. We have now determined that it is necessary to 
require the overhaul or replacement of the carriage spindles, and this 
proposed AD follows from that determination.

[[Page 10189]]

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
737-57A1218, Revision 3, dated July 25, 2002. (Boeing Alert Service 
Bulletin 737-57A1277, dated July 25, 2002, was referenced in the 
existing AD as the appropriate source of service information for 
accomplishment of the inspections to find discrepancies of each 
carriage spindle, and corrective action, if necessary.) Service 
Bulletin 737-57A1218 describes procedures for replacement or overhaul 
of each carriage spindle (two on each flap) of the left and right 
outboard mid-flaps. Such replacement or overhaul would end the 
repetitive inspections specified in Service Bulletin 737-57A1277. 
Accomplishment of the actions specified in Service Bulletin 737-57A1218 
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 supersede AD 2002-22-05 to continue to require 
repetitive inspections to find cracks, fractures, or corrosion of each 
carriage spindle of the left and right outboard mid-flaps; and 
corrective action, if necessary. This new action would mandate the 
previously optional overhaul or replacement of the carriage spindles, 
which would end the repetitive inspections required by the existing AD. 
The actions would be required to be accomplished in accordance with 
Service Bulletin 737-57A1218, Revision 3, except as discussed below.

Difference Between Service Information and Proposed AD

    The service bulletin references Boeing 737 Overhaul Manual, chapter 
57-53-35 (for Model 737-100, -200, and -200C series airplanes), and 
chapter 57-53-36 (for Model 737-300, -400, and -500 series airplanes), 
for the procedures for the overhaul specified in the proposed AD. Those 
chapters reference Boeing 737 Standard Overhaul Practices Manual (SOPM) 
chapter 20-42-09, titled, ``Electro-deposited Nickel Plating,'' for the 
nickel plating procedures. The amount of nickel plating required to 
restore functional capability and part geometry have made certain 
processing steps critical within the plating process for the spindle 
region of the flap carriage. The processing steps are specified in 
paragraph (d) of this AD, and are necessary to prevent structural 
failures of the carriage spindle due to hydrogen embrittlement. These 
processing steps have been identified by the manufacturer as critical 
details of the plating process, and Boeing Alert Service Bulletin 737-
57A1218, Revision 3, is being revised to reflect these requirements.

Cost Impact

    There are approximately 3,132 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 1,384 airplanes of U.S. 
registry would be affected by this proposed AD.
    The inspections that are currently required by AD 2002-22-05 take 
approximately 10 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 $830,400, or $600 per airplane.
    It would take approximately 2 work hours per airplane to accomplish 
the new detailed inspection, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the inspection 
proposed by this AD on U.S. operators is estimated to be $166,080, or 
$120 per airplane, per inspection cycle.
    Should an operator be required to accomplish the overhaul, it would 
take 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 overhaul proposed by this AD is estimated to be 
$1,920 per airplane.
    Should an operator be required to accomplish the replacement, it 
would take approximately 32 work hours per airplane to accomplish, at 
an average labor rate of $60 per work hour. Required parts would cost 
approximately $45,000 per carriage spindle. Based on these figures, the 
cost impact of the replacement proposed by this AD is estimated to be 
$46,920 per spindle, per airplane.
    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. 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 39-12929 (67 FR 
66316, October 31, 2002), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 2002-NM-219-AD. Supersedes AD 2002-22-05, Amendment 
39-12929.

    Applicability: All Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes; 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

[[Page 10190]]

alternative method of compliance in accordance with paragraph (f) 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 severe flap asymmetry due to fractures of the 
carriage spindles on an outboard mid-flap, which could result in 
reduced control or loss of controllability of the airplane, 
accomplish the following:

Restatement of Requirements of AD 2002-22-05

Repetitive Inspections

    (a) Do general visual and nondestructive test (NDT) inspections 
of each carriage spindle (two on each flap) of the left and right 
outboard mid-flaps to find cracks, fractures, or corrosion at the 
later of the times specified in paragraphs (a)(1) and (a)(2) of this 
AD, as applicable, per the Work Instructions of Boeing Alert Service 
Bulletin 737-57A1277, dated July 25, 2002. Repeat the inspections at 
least every 180 days until paragraph (b) or (c) of this AD is done, 
as applicable.
    (1) Before the accumulation of 12,000 total flight cycles or 8 
years in-service on new or overhauled carriage spindles, whichever 
is first.
    (2) Within 90 days after November 15, 2002 (the effective date 
of AD 2002-22-05, amendment 39-12929).

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to detect obvious damage, failure, 
or irregularity. This level of inspection is made from within 
touching distance unless otherwise specified. A mirror may be 
necessary to enhance visual access to all exposed surfaces in the 
inspection area. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or droplight and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Corrective Action

    (b) If any crack, fracture, or corrosion is found during any 
inspection required by paragraph (a) of this AD: Before further 
flight, do the applicable actions for that spindle as specified in 
paragraph (b)(1) or (b)(2) of this AD, per the Work Instructions of 
Boeing Alert Service Bulletin 737-57A1277, dated July 25, 2002. Then 
repeat the inspections required by paragraph (a) of this AD every 
12,000 flight cycles or 8 years, whichever is first, on the 
overhauled or replaced spindle only.
    (1) If any corrosion is found in the carriage spindle, overhaul 
the spindle.
    (2) If any crack or fracture is found in the carriage spindle, 
replace with a new or overhauled carriage spindle.

    Note 3: Although Boeing Alert Service Bulletin 737-57A1277, 
dated July 25, 2002, recommends that operators report inspection 
findings of any crack or fracture in the carriage spindle to the 
manufacturer, this AD does not contain such a reporting requirement.

New Requirements of This AD

Overhaul or Replacement

    (c) Overhaul or replace, as applicable, all four carriage 
spindles (two on each flap) of the left and right outboard mid-flaps 
at the applicable time specified in paragraph (c)(1) or (c)(2) of 
this AD, per the Work Instructions of Boeing Alert Service Bulletin 
737-57A1218, Revision 3, dated July 25, 2002. Then repeat the 
applicable overhaul or replacement every 12,000 flight cycles or 8 
years, whichever is first. Accomplishment of this paragraph ends the 
repetitive inspections required by paragraphs (a) and (b) of this 
AD.
    (1) For Model 737-100, -200, and -200C series airplanes, 
overhaul or replace at the later of the times specified in 
paragraphs (c)(1)(i) and (c)(1)(ii) of this AD.
    (i) Before the accumulation of 12,000 total flight cycles on the 
carriage spindle, or within 8 years since overhaul of the spindle or 
installation of a new spindle, whichever is first.
    (ii) Within 1 year after the effective date of this AD.
    (2) For Model 737-300, -400, and -500 series airplanes, overhaul 
or replace at the later of the times specified in paragraphs 
(c)(2)(i) and (c)(2)(ii) of this AD.
    (i) Before the accumulation of 12,000 total flight cycles on the 
carriage spindle, or within 8 years since overhaul of the spindle or 
installation of a new spindle, whichever is first.
    (ii) Within 2 years after the effective date of this AD.
    (d) During accomplishment of any overhaul required by paragraph 
(c) of this AD, use the procedures specified in paragraphs (d)(1) 
and (d)(2) of this AD during application of the nickel plating of 
the carriage spindle in addition to those specified in Boeing 737 
Standard Overhaul Practices Manual, Chapter 20-42-09.
    (1) Begin the hydrogen embrittlement relief bake within 10 hours 
after application of the plating, or less than 24 hours after the 
current was first applied to the part, whichever is first.
    (2) The maximum thickness of the nickel plating that is 
deposited in any one plating/baking cycle must not exceed 0.020 
inch.
    (e) Overhauling or replacing the carriage spindles before the 
effective date of this AD, in accordance with Boeing Alert Service 
Bulletin 737-57A1277, dated July 25, 2002, is considered acceptable 
for compliance with the overhaul or replacement specified in 
paragraph (c) of this AD.

Alternative Methods of Compliance

    (f) 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.

    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

    (g) 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 26, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-4990 Filed 3-3-03; 8:45 am]
BILLING CODE 4910-13-P