Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes

[Federal Register Volume 68, Number 24 (Wednesday, February 5, 2003)]
[Rules and Regulations]
[Pages 5819-5822]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-2496]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-240-AD; Amendment 39-13047; AD 2003-03-22]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737-600, -700, -700C, -800, and -900 
series airplanes, that requires installing speedbrake limitation 
placards in the

[[Page 5820]]

flight compartment, and revising the Limitations Section of the 
Airplane Flight Manual to ensure the flightcrew is advised not to 
extend the speedbrake lever beyond the flight detent. For certain 
airplanes, this AD requires modifying the elevator and elevator tab 
assembly. This action is necessary to prevent severe vibration of the 
elevator and elevator tab assembly, which could result in severe damage 
to the horizontal stabilizer followed by possible loss of the elevator 
tab and consequent loss of controllability of the airplane. This action 
is intended to address the identified unsafe condition.

DATES: Effective March 12, 2003.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 12, 2003.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Nancy H. Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6440; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 737-600, -
700, -700C, -800, and -900 series airplanes was published in the 
Federal Register on November 15, 2002 (67 FR 69157). That action 
proposed to require installing speedbrake limitation placards in the 
flight compartment, and revising the Limitations Section of the 
Airplane Flight Manual (AFM) to ensure the flightcrew is advised not to 
extend the speedbrake lever beyond the flight detent. For certain 
airplanes, that action also proposed to require modifying the elevator 
and elevator tab assembly.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received. One commenter concurs with the proposed AD. Two 
commenters state that they have no comments on the proposed AD.

Request To Clarify Certain Language in Paragraph (a)(2)

    One commenter asks that certain language, as specified in paragraph 
(a)(2) of the proposed AD, be clarified. The commenter notes that the 
current language, which is to be included in the AFM, states the 
following: ``Do not extend the speedbrake lever beyond the flight 
detent in flight.'' That statement, as written, does not match the 
language specified in the existing AFM. The language should be changed, 
for clarification, to match the AFM language and should state: ``In 
flight, do not extend the speedbrake lever beyond the FLIGHT detent.''
    The FAA agrees with the commenter in that the language used in 
paragraph (a)(2) of the AD should be clarified to match the AFM 
language. We have changed paragraph (a)(2) of this final rule 
accordingly.

Request To Change Discussion Section

    The same commenter asks that the Discussion section of the proposed 
AD be changed to remove the reference to Boeing Model 737-900 series 
airplanes from the first sentence. That sentence states, ``The FAA has 
received several reports of excessive in-flight vibrations of the 
elevator and elevator tab on certain Boeing Model 737-600, -700, -700C, 
-800, and -900 series airplanes.'' The commenter notes that no 
excessive in-flight vibrations of the elevator and elevator tab have 
occurred on Model 737-900 series airplanes.
    The same commenter asks that certain terminology in the Discussion 
section of the proposed AD be changed. That section reads, in part, 
``[t]he elevator and elevator tab are susceptible to excessive 
vibration and, under certain conditions, limit-cycle flutter. These 
vibration events have been attributed to loose or missing components, 
excessive wear, or excessive freeplay of the tab.'' The commenter 
requests that it be changed to, ``[t]he elevator and elevator tab are 
susceptible to excessive vibration and, under certain conditions, 
limit-cycle oscillation (LCO). These vibration events have been 
attributed to lack of torsional rigidity (in the case of LCO); or 
missing components, excessive wear, or excessive freeplay of the tab.'' 
The commenter states that LCO is the accepted and proper term to use 
when referring to the severe vibrations associated with lack of 
torsional stiffness.
    We acknowledge that no excessive in-flight vibrations of the 
elevator and elevator tab have been reported on Model 737-900 series 
airplanes in-service. The intent of the Discussion section is to 
provide the background and events that prompted the proposed AD, and to 
specify that vibrations did occur on Model 737-600, -700, -700C, and -
800 series airplanes in-service.
    We acknowledge that the term ``lack of torsional rigidity'' is a 
valid term and could be used to describe a design deficiency that also 
contributes to excessive in-flight vibration. However, the terms 
``LCO'' and ``LCF'' are not commonly used terms in the airline 
industry; these terms are used primarily by airplane manufacturers. We 
have concluded that the term ``high amplitude oscillations of the 
elevator tab'' best describes the condition in a manner understood by 
the airline industry.
    Since the Discussion section of a proposed AD is not restated in a 
final rule, no change to this final rule is necessary to address the 
issues raised by the commenters.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 1,174 airplanes of the affected design in 
the worldwide fleet. We estimate that 550 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 1 work hour per airplane to accomplish 
the required placard installation, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the required 
installation on U.S. operators is estimated to be $33,000, or $60 per 
airplane.
    It will take approximately 1 work hour per airplane to accomplish 
the required AFM revision, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the required revision 
on U.S. operators is estimated to be $33,000, or $60 per airplane.
    It will take approximately 88 work hours per airplane to accomplish 
the required modification of the elevator and elevator tab assembly, at 
an average labor rate of $60 per work hour. The FAA has been advised by 
Boeing that the manufacturer will provide parts for the elevator/tab 
retrofit, including

[[Page 5821]]

shipping, at no cost to operators. The manufacturer will have operators 
``exchange'' their existing parts for new parts to support the retrofit 
program. Based on this information, the cost impact of the required 
modification on U.S. operators is estimated to be $2,904,000, or $5,280 
per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the 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 adopted herein will 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 final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2003-03-22 Boeing: Amendment 39-13047. Docket 2002-NM-240-AD.
    Applicability: Model 737-600, -700, -700C, -800, and -900 series 
airplanes; line numbers 1 through 1174 inclusive; 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 severe vibration of the elevator and elevator tab 
assembly, which could result in severe damage to the horizontal 
stabilizer followed by possible loss of the elevator tab and 
consequent loss of controllability of the airplane, accomplish the 
following:

Airplane Flight Manual (AFM) Revision/Placard Installation

    (a) For Model 737-600, -700, -700C, -800, and -900 series 
airplanes having line numbers 1 through 1043 inclusive: Within 90 
days after the effective date of this AD, do the actions specified 
in paragraphs (a)(1) and (a)(2) of this AD.
    (1) Install a speedbrake limitation placard on the P1-1 and P3-3 
panel assemblies per Figure 1 or Figure 2, as applicable, of 
paragraph 3.B., ``Work Instructions,'' of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-11A1109, dated 
March 28, 2002.
    (2) Revise the Limitations Section of the FAA-approved AFM to 
include the following statement (this may be accomplished by 
inserting a copy of this AD in the AFM): ``In flight, do not extend 
the speedbrake lever beyond the FLIGHT detent.''

Modification

    (b) For Model 737-600, -700, -700C, and -800 series airplanes 
having line numbers 1 through 1174 inclusive: Before the 
accumulation of 18,000 total flight cycles, or within 2 years after 
the effective date of this AD, whichever occurs first, modify the 
elevator and elevator tab assemblies (including installation of a 
new clevis fitting and a new tab mechanism on the horizontal 
stabilizer and, for certain airplanes, examination of the hinge 
plates on the stabilizer trailing edge to make sure the specified 
hinges are installed; changes to the seals in the balance bays; and 
installation of new elevators and tab assemblies, followed by 
adjustments and tests of the new installation), per the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
55A1080, dated September 19, 2002.
    (c) Accomplishment of the modification required by paragraph (b) 
of this AD terminates the actions required by the ADs specified in 
the following table:

------------------------------------------------------------------------
                 AD Number                        Amendment Number
------------------------------------------------------------------------
AD 99-15-09...............................  39-11229
AD 99-18-01...............................  39-11267
AD 2001-08-09.............................  39-12186
AD 2001-09-51.............................  39-12251
AD 2001-12-51.............................  39-12294
AD 2001-14-05.............................  39-12315
AD 2002-08-20.............................  39-12732
AD 2002-08-52.............................  39-12727
------------------------------------------------------------------------

Operator's Equivalent Procedure

    (d) If the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-55A1080, dated September 19, 2002, specify that the 
actions may be accomplished in accordance with an operator's 
``equivalent procedure:'' The actions must be accomplished per the 
applicable chapter of the Boeing 737 Airplane Maintenance Manual 
specified in the alert service bulletin.

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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permit

    (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.

Incorporation by Reference

    (g) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Alert Service Bulletin 737-11A1109, 
dated March 28, 2002; and Boeing Alert Service Bulletin 737-55A1080, 
dated September 19, 2002; as applicable. This incorporation by 
reference was approved by the Director of the Federal Register in 
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, 
Seattle, Washington 98124-2207. Copies may be inspected at the FAA, 
Transport Airplane

[[Page 5822]]

Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

Effective Date

    (h) This amendment becomes effective on March 12, 2003.


    Issued in Renton, Washington, on January 29, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-2496 Filed 2-4-03; 8:45 am]
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