Document ID: FAA-2008-0413-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 737-600, -700, -700C, - 800, -900, and 900ER Series Airplanes
Posted Date: 2008-04-24T04:00Z

[Federal Register: April 24, 2008 (Volume 73, Number 80)]
[Proposed Rules]               
[Page 22090-22092]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24ap08-10]                         

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0413; Directorate Identifier 2008-NM-003-AD]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Boeing Model 737-600, -700, -700C, -800, -900, and 900ER series 
airplanes. This proposed AD would require

[[Page 22091]]

replacing the pushrods for the left and right elevator tab control 
mechanisms with new, improved pushrods. This proposed AD results from a 
report of a rod end fracture on a rudder Power Control Unit (PCU) 
control rod, which is similar to the ones used for the elevator tab 
pushrods. Analysis revealed that the fractured rod end had an incorrect 
hardness, which had probably occurred during the manufacture of the 
control rod. We are proposing this AD to prevent fracture of the 
elevator tab pushrod ends, which could result in excessive in-flight 
vibrations of the elevator tab, possible loss of the elevator tab, and 
consequent loss of controllability of the airplane.

DATES: We must receive comments on this proposed AD by June 9, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this AD, contact Boeing 
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Tamara Anderson, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6421; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0413; 
Directorate Identifier 2008-NM-003-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We have received a report of a rod end fracture on a rudder Power 
Control Unit (PCU) control rod, which is similar to the ones used for 
the elevator tab pushrods. An operator found a broken rudder PCU 
control rod during heavy maintenance of a Model 737-800 airplane. 
Analysis revealed that the fractured rod end had an incorrect hardness, 
which had probably occurred during the manufacture of the control rod. 
During the manufacturing process, specific areas of the control rods 
are to be masked off to prevent the application of the heat treatment/
carburization process in those areas. But at different site locations 
of the supplier, the heat treatment/carburization process was done 
differently, which resulted in the application of the heat treatment/
carburization process of some control rods in incorrect areas. This 
caused an incorrect hardness of the hollow shanks of the rod ends, and 
resulted in the occurrence of cracks at the time of manufacture. 
Further analysis revealed that all control rods made by the supplier 
were also affected by the incorrect manufacturing procedure. 
Subsequently, an improved design of the control rod was developed to 
change from hollow shank rod ends to solid shank rod ends, which would 
prevent the problems with the heat treatment/carburization process 
during manufacture. Fracture of the elevator tab pushrod ends could 
result in excessive in-flight vibrations of the elevator tab, possible 
loss of the elevator tab, and consequent loss of controllability of the 
airplane.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-27-
1284, dated November 28, 2007. The service bulletin describes 
procedures for replacing the pushrods for the left and right elevator 
tab control mechanism with new, improved pushrods. The service bulletin 
specifies doing the replacement within 4 years after the date on the 
service bulletin.

Other Related Rulemaking

    On January 29, 2003, the FAA issued AD 2003-03-22, amendment 39-
13047 (68 FR 5819, February 5, 2003), which applies to certain Boeing 
Model 737-600, -700, -700C, -800, and -900 series airplanes. AD 2003-
03-22 requires accomplishing the modification in accordance with Boeing 
Alert Service Bulletin 737-55A1080, dated September 19, 2002, and 
Service Bulletin 737-27-1284 specifies prior or concurrent 
accomplishment of Service Bulletin 737-55A1080. AD 2003-03-22 requires 
installing speedbrake limitation placards in the 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 Model 737-600, -700, -700C, -800 series 
airplanes having line numbers 1 through 1174 inclusive, AD 2003-03-22 
requires modifying the elevator and elevator tab assembly before the 
accumulation of 18,000 total flight cycles, or within 2 years after 
March 12, 2003, whichever occurs first.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously.

Costs of Compliance

    We estimate that this proposed AD would affect 715 airplanes of 
U.S. registry. We also estimate that it would take about 4 work-hours 
per product to comply with this proposed AD. The average labor rate is 
$80 per work-hour. Required parts would cost about $8,036 per product. 
Based on these figures, we estimate the cost of this proposed AD to the 
U.S. operators to be $5,974,540, or $8,356 per product.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue

[[Page 22092]]

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 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 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. 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

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 FAA amends Sec.  39.13 by adding the following new AD:

Boeing: Docket No. FAA-2008-0413; Directorate Identifier 2008-NM-
003-AD.

Comments Due Date

    (a) We must receive comments by June 9, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800, 
-900, and 900ER series airplanes, certificated in any category; line 
numbers 1 through 2196 inclusive.

Unsafe Condition

    (d) This AD results from a report of a rod end fracture on 
rudder Power Control Unit (PCU) control rod, which is similar to the 
ones used for the elevator tab pushrods. Analysis revealed that the 
fractured rod end had an incorrect hardness, which had probably 
occurred during the manufacture of the control rod. We are issuing 
this AD to prevent fracture of the elevator tab pushrod ends, which 
could result in excessive in-flight vibrations of the elevator tab, 
possible loss of the elevator tab, and consequent loss of 
controllability of the airplane.

Compliance

    (e) Comply with this AD within the compliance times specified, 
unless already done.

Pushrod Replacement

    (f) At the time specified in paragraph 1.E., ``Compliance,'' of 
Boeing Special Attention Service Bulletin 737-27-1284, dated 
November 28, 2007; except, where the service bulletin specifies a 
compliance time after the date on the service bulletin, this AD 
requires compliance within the specified compliance time after the 
effective date of this AD: Replace the pushrods for the left and 
right elevator tab control mechanisms with new, improved pushrods by 
doing all the actions in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-27-
1284, dated November 28, 2007.

Parts Installation

    (g) As of the effective date of this AD, no person may install a 
pushrod assembly, part number 65-45166-24, on any airplane.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, ATTN: Tamara Anderson, Aerospace Engineer, Airframe Branch, 
ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6421; fax (425) 917-6590; 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your appropriate principal inspector (PI) in the FAA 
Flight Standards District Office (FSDO), or lacking a PI, your local 
FSDO.
    (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.

    Issued in Renton, Washington, on April 15, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-8911 Filed 4-23-08; 8:45 am]

BILLING CODE 4910-13-P