[Federal Register Volume 66, Number 171 (Tuesday, September 4, 2001)]
[Proposed Rules]
[Pages 46247-46250]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-22092]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-394-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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[[Page 46248]]

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Boeing Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes. For certain airplanes, 
this proposal would require a one-time inspection or a review of the 
maintenance records of the airplane to determine if a particular 
control rod barrel for the aileron tabs is installed, and follow-on 
repetitive inspections for cracking of the control rod barrels and 
replacement of the control rod barrels with new barrels, if necessary. 
Such replacement would terminate the repetitive inspections. For all 
airplanes, this proposal would prohibit installation of a certain 
control rod barrel for the aileron tabs. This action is necessary to 
prevent the disconnection of an aileron tab, which could lead to severe 
airframe vibrations; consequent damage to the aileron tab, aileron, and 
wing; and loss of controllability of the airplane. This action is 
intended to address the identified unsafe condition.

DATES: Comments must be received by October 19, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-394-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. 2000-NM-394-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: James Blilie, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2131; 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     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.
     For each issue, state what specific change to the proposed 
AD is being requested.
     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 2000-NM-394-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-394-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report indicating that a control rod barrel 
for the aileron tabs was found broken in half on a Boeing Model 737-500 
series airplane. An examination of the broken control rod barrel 
revealed incorrect machining of an internal thread relief groove during 
manufacturing, which resulted in extremely thin walls on the control 
rod barrel. Investigation has revealed that this condition may exist in 
an entire lot of parts. This condition, if not corrected, could result 
in disconnection of an aileron tab, which could lead to severe airframe 
vibrations; consequent damage to the aileron tab, aileron, and wing; 
and loss of controllability of the airplane.
    Though the broken control rod barrel was found on a Model 737-500 
series airplane, the same control rod barrels may be installed on 
certain other Model 737-100, -200, -200C, -300, and -400 series 
airplanes.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Special Attention Service 
Bulletin 737-27-1223, dated October 21, 1999, which describes 
procedures for a one-time inspection to determine whether the control 
rod barrels of the aileron tabs are from the affected lot, and follow-
on repetitive inspections for cracking of the control rod barrels and 
replacement of the control rod barrels with new control rod barrels, if 
necessary. The procedures involve inspecting for a control rod barrel 
with part number 69-60083-1, which is accomplished by determining the 
color of the control rod barrels. (Control rod barrels installed on 
airplanes between line numbers 1 through 3110 inclusive were painted 
white. Control rod barrels installed on airplanes with line numbers 
3111 and subsequent were painted gray.) For white control rod barrels, 
the service bulletin describes procedures for follow-on repetitive 
detailed visual inspections for cracking of the control rod barrels, 
and replacement of the control rod barrels with new control rod 
barrels. Replacement of white-colored control rod barrels with new 
control rod barrels eliminates the need for the repetitive inspections. 
If any cracked control rod barrel is found, all control rod barrels 
must be replaced at the same time because, as stated above, the 
discrepancy may exist in the entire lot of parts. The service bulletin 
specifies that all control rod barrels having part number 69-60083-1 
(which are painted white) must eventually be replaced, regardless of 
whether they are cracked or not. 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

[[Page 46249]]

specified in the service bulletin described previously, except as 
discussed below under the heading ``Difference Between Proposed Rule 
and Service Bulletin.'' In lieu of the inspection for control rod 
barrels with a certain part number by determining the color of the 
control rod barrels, which is described in the service bulletin, the 
FAA has determined that a review of the maintenance records of the 
airplane to determine if a particular part number of control rod barrel 
is installed is acceptable for compliance with this proposed AD. The 
proposed AD also would require that operators report findings of 
discrepant barrels to the Boeing Certification Management Office.

Difference Between Proposed Rule and Service Bulletin

    This proposed rule differs from the service bulletin in that it 
would apply to all Boeing Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes. The service bulletin lists only Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes having line numbers 1 
through 3110 inclusive. The airplane manufacturer delivered airplanes 
having line numbers 3111 and subsequent with control rod barrels for 
the aileron tabs having a different part number than the ones subject 
to this AD. However, the FAA has determined that it is possible that a 
control rod barrel subject to this AD could be installed after the 
effective date of this AD on an airplane after line number 3110. Thus, 
it is necessary to make the requirements of this AD applicable to all 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes.

Cost Impact

    There are approximately 2,900 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 1,250 airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 1 work hour per airplane to accomplish 
the proposed inspection to determine the color of the control rod 
barrels for the aileron tabs or the proposed review of maintenance 
records, at an average labor rate of $60 per work hour. Based on these 
figures, the cost impact of this proposed inspection on U.S. operators 
is estimated to be $75,000, or $60 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 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.
    If subject control rod barrels are installed, it would take 
approximately 1 work hour to accomplish the proposed follow-on 
inspections, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of this proposed follow-on inspection is 
estimated to be $60 per airplane, per inspection cycle.
    If subject control rod barrels are installed, it would take 
approximately 2 work hours to replace each control rod barrel, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of this proposed replacement is estimated to be $120 per 
airplane. Up to four control rod barrels (two for each aileron) may 
need to be replaced on each airplane.

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 adding the following new 
airworthiness directive:

Boeing: Docket 2000-NM-394-AD.

    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 
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 a disconnected aileron tab, which could lead to 
severe airframe vibrations; consequent damage to the aileron tab, 
aileron, and wing; and loss of controllability of the airplane; 
accomplish the following:

One-Time Inspection

    (a) Within 3,200 flight hours after the effective date of this 
AD, do paragraph (a)(1) or (a)(2) of this AD.
    (1) Do a one-time general visual inspection to determine whether 
an aileron tab control rod barrel having part number 69-60083-1 is 
installed by determining the color of the control rod barrels, 
according to Boeing Special Attention Service Bulletin 737-27-1223, 
dated October 21, 1999. No further action is required by this AD for 
gray-colored control rod barrels. If any white-colored control rod 
barrel with part number 69-60083-1 is installed, or if the color or 
part number of any control rod barrel cannot be determined, do 
paragraph (b) of this AD.
    (2) Review the maintenance records for the airplane to determine 
whether an aileron tab control rod barrel having part number 69-
60083-1 is installed. If no control rod barrel with that part number 
is installed, no further action is required by this AD. If any 
control rod barrel with that part number is installed, do paragraph 
(b) of this AD.

    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 under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-

[[Page 46250]]

light, 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.''

Follow-On Actions: Repetitive Inspections and Replacement

    (b) For airplanes that have a control rod barrel for the aileron 
tabs having part number 69-60083-1 or a control rod barrel on which 
the color or part number cannot be determined: Within 3,200 flight 
hours after the effective date of this AD, do a detailed visual 
inspection for cracking of the affected control rod barrels 
according to Boeing Special Attention Service Bulletin 737-27-1223, 
dated October 21, 1999.

    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.''

    (1) If no cracking is found, repeat the inspection for cracking 
at least every 3,200 flight cycles, AND, within 20,000 flight cycles 
after the effective date of this AD, replace all affected control 
rod barrels for the aileron tabs with new or reworked control rod 
barrels, according to the service bulletin. Such replacement 
terminates the repetitive inspections.
    (2) If any cracking is found, before further flight, replace all 
control rod barrels with new or reworked control rod barrels, 
according to the service bulletin.

    Note 4: If any control rod barrel for the aileron tab is 
cracked, all affected control rod barrels on the airplane must be 
replaced at the same time because the discrepancy may exist in the 
entire lot of parts.

Reporting Requirement

    (c) If any cracked control rod barrel for the aileron tabs is 
found during the inspections required by paragraph (b) of this AD, 
report findings to the FAA Certification Management Office, 1601 
Lind Avenue, SW., Renton, Washington 98055-4056, at the applicable 
time specified in paragraph (c)(1) or (c)(2) of this AD. Information 
collection requirements contained in this regulation have been 
approved by the Office of Management and Budget (OMB) under the 
provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et 
seq.) and have been assigned OMB Control Number 2120-0056.
    (1) For airplanes on which the inspection is accomplished after 
the effective date of this AD: Submit the report within 10 days 
after performing the inspection required by paragraph (b) of this 
AD.
    (2) For airplanes on which the inspection has been accomplished 
prior to the effective date of this AD: Submit the report within 10 
days after the effective date of this AD.

Spares

    (d) For all airplanes: As of the effective date of this AD, no 
person may install a control rod barrel for the aileron tab having 
part number 69-60083-1 on any airplane.

Alternative Methods of Compliance

    (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. 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 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

    (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.

    Issued in Renton, Washington, on August 27, 2001.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-22092 Filed 8-31-01; 8:45 am]
BILLING CODE 4910-13-P