[Federal Register Volume 71, Number 26 (Wednesday, February 8, 2006)]
[Proposed Rules]
[Pages 6417-6420]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-1687]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-23815; Directorate Identifier 2005-NM-222-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking.

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Boeing Model 737 airplanes. This proposed AD would require 
repetitive measurement of the freeplay of both

[[Page 6418]]

aileron balance tabs; repetitive lubrication of the aileron balance tab 
hinge bearings and rod end bearings; and related investigative and 
corrective actions if necessary. This proposed AD results from reports 
of freeplay-induced vibration of the aileron balance tab. The potential 
for vibration of the control surface should be avoided because the 
point of transition from vibration to divergent flutter is unknown. We 
are proposing this AD to prevent excessive vibration of the airframe 
during flight, which could result in loss of control of the airplane.

DATES: We must receive comments on this proposed AD by March 27, 2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Dennis Stremick, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6450; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2006-
23815; Directorate Identifier 2005-NM-222-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    We have received three reports of freeplay-induced vibration of the 
aileron balance tab on Boeing Model 737 airplanes. Excessive corrosion 
and wear of components and/or interfaces allows excessive freeplay 
movement of the control surfaces and can cause excessive vibration of 
the airframe during flight. The potential for vibration of the control 
surface should be avoided because the point of transition from 
vibration to divergent flutter is unknown. When divergent flutter 
occurs, the amplitude of each cycle or oscillation is larger than the 
previous one and the surface can quickly reach its structural limits. 
Excessive vibration of the airframe, if not corrected, could result in 
loss of control of the airplane.

Relevant Service Information

    We have reviewed the following Boeing service bulletins:
     For Boeing Model 737-100, -200, -200C, -300, -400, -500 
series airplanes: Boeing Special Attention Service Bulletin 737-27-
1272, dated September 29, 2005.
     For Boeing Model 737-600, -700, -700C, -800 and -900 
series airplanes: Boeing Special Attention Service Bulletin 737-27-
1273, dated September 29, 2005.
    The service bulletins describe procedures for repetitive 
measurement of the freeplay of both aileron balance tabs. If the 
freeplay exceeds certain specified limits, the service bulletins 
describe procedures for doing applicable related investigative and 
corrective actions. These related investigative and corrective actions 
include doing a visual inspection for wear of the affected components 
such as bearings, bolts, and bushings; and repairing or replacing the 
affected part if necessary. The corrective actions also include 
repeating the freeplay measurement and applicable related investigative 
and corrective actions until the freeplay is within acceptable limits. 
The service bulletins also describe procedures for repetitive 
lubrication of the aileron balance tab hinge bearings and rod end 
bearings. The service bulletins note that if the freeplay measurement 
and a lubrication cycle are due at the same time, the freeplay 
measurement must be satisfactory before the lubrication is done. 
Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    There are about 5,651 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD. No parts are necessary 
to accomplish either action.

[[Page 6419]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                  Number of
                                                 Average     Cost per airplane      U.S.-
             Action                Work hours   labor rate           $            registered     Fleet cost  $
                                               per hour  $                        airplanes
----------------------------------------------------------------------------------------------------------------
Freeplay measurement............            8           65  520, per                   2,280  1,185,600, per
                                                             measurement cycle.                measurement
                                                                                               cycle.
Lubrication.....................            4           65  260, per                   2,280  592,800, per
                                                             lubrication cycle.                lubrication
                                                                                               cycle.
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-23815; Directorate Identifier 2005-NM-
222-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by March 27, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-100, -200, -200C, -
300, -400, -500, -600, -700, -700C, -800, and -900 series airplanes; 
certificated in any category.

Unsafe Condition

    (d) This AD results from three reports of freeplay-induced 
vibration of the aileron balance tab. The potential for vibration of 
the control surface should be avoided because the point of 
transition from vibration to divergent flutter is unknown. We are 
issuing this AD to prevent excessive vibration of the airframe 
during flight, which could result in loss of control of the 
airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Service Bulletin References

    (f) The term ``service bulletin,'' as used in this AD, means the 
Accomplishment Instructions of the following service bulletins, as 
applicable:
    (1) For Boeing Model 737-100, -200, -200C, -300, -400, -500 
series airplanes: Boeing Special Attention Service Bulletin 737-27-
1272, dated September 29, 2005.
    (2) For Boeing Model 737-600, -700, -700C, -800 and -900 series 
airplanes: Boeing Special Attention Service Bulletin 737-27-1273, 
dated September 29, 2005.

Repetitive Measurements

    (g) Within 18 months after the effective date of this AD: 
Measure the freeplay of both aileron control balance tabs. Repeat 
the measurement thereafter at the applicable interval in paragraph 
(g)(1) or (g)(2) of this AD. Do all actions required by this 
paragraph in accordance with the applicable service bulletin.
    (1) For Boeing Model 737-100, -200, and -200C series airplanes: 
At intervals not to exceed 6,000 flight hours or 24 months, 
whichever occurs first.
    (2) For Boeing Model 737-300, -400, -500, -600, -700, -700C, -
800 and -900 series airplanes: At intervals not to exceed 8,000 
flight hours or 24 months, whichever occurs first.

Related Investigative and Corrective Actions

    (h) If any measurement found in paragraph (g) of this AD is 
outside the acceptable limits specified in the service bulletin: 
Before further flight, do the applicable related investigative and 
corrective actions in accordance with the applicable service 
bulletin.

Repetitive Lubrication

    (i) Within 9 months after the effective date of this AD: 
Lubricate the aileron balance tab components specified in the 
applicable service bulletin. Repeat the lubrication thereafter at 
the applicable interval in paragraph (i)(1), (i)(2), or (i)(3) of 
this AD. Do all actions required by this paragraph in accordance 
with the applicable service bulletin.
    (1) For Boeing Model 737-100, -200, and -200C series airplanes: 
At intervals not to exceed 3,000 flight hours or 9 months, whichever 
occurs first.
    (2) For Boeing Model 737-300, -400, -500, -600, -700, -700C, -
800, and -900 series airplanes, on which BMS 3-33 grease is not 
used: At intervals not to exceed 3,000 flight hours or 9 months, 
whichever occurs first.
    (3) For Boeing Model 737-300, -400, -500, -600, -700, -700C, -
800, and -900 series airplanes, on which BMS 3-33 grease is used: At 
intervals not to exceed 4,000 flight hours or 12 months, whichever 
occurs first.

Concurrent Repetitive Cycles

    (j) If a freeplay measurement required by paragraph (g) of this 
AD and a lubrication cycle required by paragraph (i) of this AD are

[[Page 6420]]

due at the same time or will be accomplished during the same 
maintenance visit, the freeplay measurement and applicable related 
investigative and corrective actions must be done before the 
lubrication is accomplished.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

    Issued in Renton, Washington, on January 30, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-1687 Filed 2-7-06; 8:45 am]
BILLING CODE 4910-13-P