
[Federal Register: March 13, 2008 (Volume 73, Number 50)]
[Proposed Rules]               
[Page 13480-13483]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr13mr08-12]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0273; Directorate Identifier 2007-NM-369-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 747-400, 747-400D, and 
747-400F Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) that applies to all Boeing Model 747-400, 747-400D, and 
747-400F series airplanes. The existing AD currently requires reviewing 
airplane maintenance records, doing repetitive inspections for cracking 
of the yaw damper actuator portion of the upper and lower rudder power 
control modules (PCMs), replacing the PCMs if necessary, and reporting 
all airplane maintenance records review and inspection results to the 
manufacturer. This proposed AD would limit the applicability, reduce 
the initial inspection threshold and repetitive interval, remove the 
reporting requirement, and require installation of a secondary 
retention device for the yaw damper modulating piston. Installation of 
the secondary retention device would terminate the repetitive 
inspection requirements. This proposed AD results from additional 
reports of failure or cracking of the PCM manifold in the area of the 
yaw damper cavity endcap at intervals well below the initial inspection 
threshold of the existing AD. We are proposing this AD to prevent an 
uncommanded left rudder hardover in the event of cracking in the yaw 
damper actuator portion of the upper or lower rudder PCMs, and 
subsequent failure of the PCM manifold, which could result in increased 
pilot workload, and possible runway departure upon landing.

DATES: We must receive comments on this proposed AD by April 14, 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.

[[Page 13481]]


FOR FURTHER INFORMATION CONTACT: Douglas Tsuji, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6487; 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-2008-0273; 
Directorate Identifier 2007-NM-369-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

    On August 30, 2006, we issued AD 2006-18-17, amendment 39-14756 (71 
FR 52999, September 8, 2006), for all Boeing Model 747-400, 747-400D, 
and 747-400F series airplanes. That AD requires reviewing airplane 
maintenance records, doing repetitive inspections for cracking of the 
yaw damper actuator portion of the upper and lower rudder power control 
modules (PCMs), replacing the PCMs if necessary, and reporting all 
airplane maintenance records review and inspection results to the 
manufacturer. That AD resulted from manufacturer findings that the 
inspections required by the existing AD (AD 2003-23-01, amendment 39-
13364, which AD 2006-18-17 superseded) must be performed at regular 
intervals. We issued AD 2006-18-17 to detect and correct cracking in 
the yaw damper actuator portion of the upper and lower rudder PCMs, 
which could result in an uncommanded left rudder hardover, consequent 
increased pilot workload, and possible runway departure upon landing.

Actions Since Existing AD Was Issued

    Since the issuance of AD 2006-18-17, there have been additional 
reports of cracked rudder PCMs in the yaw damper portion of the PCM 
manifold that failed well below the initial inspection threshold of the 
AD. As part of the National Transportation Safety Board (NTSB) and FAA 
investigation, it was determined that a permanent design modification 
must be made to the rudder PCM that prevents a left rudder hardover in 
the event of a failed rudder PCM manifold.
    The preamble to AD 2006-18-17 specified that we considered the 
requirements ``interim action.'' That AD explained that we might 
consider further rulemaking since the root cause of the cracking had 
not been determined. Because of the additional premature failures of 
the rudder PCM, the manufacturer has now developed a final action, 
which is installation of a secondary means of retention for the 
modulating piston assembly in the event of a rudder PCM manifold 
failure. Therefore, we have determined that further rulemaking is 
indeed necessary; this proposed AD follows from that determination.
    The inspection thresholds and intervals in AD 2006-18-17 correspond 
to those in Boeing Alert Service Bulletin 747-27A2397, Revision 2, 
dated September 1, 2005, which we referred to in AD 2006-18-17 as the 
appropriate source of service information for doing the initial and 
repetitive inspections. However, since we issued that AD, we have 
received additional reports of failure or cracking of the PCM manifold 
in the area of the yaw damper cavity endcap at intervals well below the 
initial inspection threshold of the existing AD. These incidents 
happened between 20,000 and 46,000 total flight hours. The initial 
flight-hour threshold in AD 2006-18-17 is 56,000 total flight hours, 
which corresponds to the threshold in Boeing Alert Service Bulletin 
747-27A2397, Revision 2. Therefore, we are proposing that operators 
accomplish the ultrasonic inspections required by AD 2006-18-17 at 
reduced inspection threshold and intervals, until the final action is 
accomplished. Boeing has no objection to the reduced inspection 
thresholds and intervals.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-27A2479, dated 
November 8, 2007. The service bulletin describes procedures for 
installing a new secondary retention device for the yaw damper piston 
assembly in both the upper and lower PCMs. The service bulletin 
specifies two options for installing the new secondary retention 
device:
     Replacing the existing PCM with a new improved PCM.
     Modifying, testing, and re-identifying the existing PCM 
while installed on the airplane.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.
    Boeing Alert Service Bulletin 747-27A2479 refers to Parker Service 
Bulletins 332700-27-312 and 333200-27-314, both dated September 13, 
2007, as additional sources of service information for modifying the 
PCM.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to develop on other airplanes of the 
same type design. For this reason, we are proposing this AD, which 
would supersede AD 2006-18-17, and retain all but the reporting 
requirement of that AD. This proposed AD would also limit the 
applicability, reduce the inspection threshold and repetitive interval, 
and require eventual installation of a secondary retention device for 
the yaw damper modulating piston. Installation of a secondary retention 
device would terminate the repetitive inspection requirements of the 
existing AD.

Explanation of Reporting Requirement

    AD 2006-18-17 requires that operators report crack findings to 
Boeing and return cracked or broken PCMs to Parker Hannifin 
Corporation. This proposed AD would not include those actions. Boeing 
has now developed a final action, so the report and parts return are no 
longer necessary.

Explanation of 30 Day Comment Period

    Operators should note that because of the critical need to prevent 
an uncommanded left rudder hardover, we have determined that a comment 
period of 30 days, rather than 45 days, is necessary in this case.

Costs of Compliance

    There are about 655 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 86 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD. The average labor rate 
is $80 per work hour.

[[Page 13482]]



                                                                     Estimated Costs
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              Action                     Work hours                    Parts                     Cost per airplane                  Fleet cost
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Ultrasonic inspection (required    4....................  None..........................  $320, per inspection cycle....  $27,520, per inspection cycle.
 by AD 2006-18-17).
Option 1--replacement (new         Up to 22.............  Up to $4,496..................  Up to $6,256..................  Up to $538,016.
 proposed action).
Option 2--modification (new        Up to 13.............  Up to $722....................  Up to $1,762..................  Up to $151,532.
 proposed action).
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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 
removing amendment 39-14756 (71 FR 52999, September 8, 2006) and adding 
the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2008-0273; Directorate Identifier 2007-NM-
369-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by April 14, 
2008.

Affected ADs

    (b) This AD supersedes AD 2006-18-17.

Applicability

    (c) This AD applies to Boeing Model 747-400, 747-400D, and 747-
400F series airplanes, certificated in any category, as identified 
in Boeing Alert Service Bulletin 747-27A2479, dated November 8, 
2007.

Unsafe Condition

    (d) This AD results from additional reports of failure or 
cracking of the power control module (PCM) manifold in the area of 
the yaw damper cavity endcap at intervals well below the initial 
inspection threshold of the existing AD. We are issuing this AD to 
prevent an uncommanded left rudder hardover in the event of cracking 
in the yaw damper actuator portion of the upper or lower rudder PCM, 
and subsequent failure of the PCM manifold, which could result in 
increased pilot workload, and possible runway departure upon 
landing.

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.

Verification of Rudder PCM/Main Manifold Time-in-Service

    (f) For any affected airplane, if it can be positively verified 
that any rudder PCM or PCM main manifold installed on that airplane 
has accumulated a different total of flight hours or flight cycles 
than the totals accumulated by that airplane, the flight cycles or 
flight hours accumulated by the rudder PCM or PCM main manifold will 
be acceptable as valid starting points for meeting the compliance 
times required by this AD.

Ultrasonic Inspections

    (g) Do an ultrasonic inspection for cracking of the yaw damper 
actuator portion of the upper and lower rudder PCMs at the 
applicable times specified in paragraph (g)(1) or (g)(2) of this AD 
in accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-27A2397, Revision 2, dated September 1, 2005. Doing the 
installation required by paragraph (j) of this AD ends the 
inspection requirements of this paragraph for that PCM.
    (1) For airplanes that have been inspected before the effective 
date of this AD in accordance with Boeing Alert Service Bulletin 
747-27A2397, dated July 24, 2003; Revision 1, dated March 31, 2005; 
or Revision 2, dated September 1, 2005: Do the ultrasonic inspection 
at the later of the times specified in paragraph (g)(1)(i) and 
(g)(1)(ii) of this AD. Repeat the inspection thereafter at intervals 
not to exceed 7,000 flight hours or 1,125 flight cycles, whichever 
occurs first, until the action required by paragraph (j) of this AD 
is accomplished.
    (i) Within 7,000 flight hours or 1,125 flight cycles after the 
prior inspection, whichever occurs first.
    (ii) Within 6 months after the effective date of this AD.
    (2) For airplanes that have not been inspected before the 
effective date of this AD in accordance with Boeing Alert Service 
Bulletin 747-27A2397, dated July 24, 2003; Revision 1, dated March 
31, 2005; or Revision 2, dated September 1, 2005: Do the ultrasonic 
inspection at the later of the times specified in paragraph 
(g)(2)(i) and (g)(2)(ii) of this AD. Repeat the inspection 
thereafter at intervals not to exceed 7,000 flight hours or 1,125 
flight cycles, whichever occurs first, until the action required by 
paragraph (j) of this AD is accomplished.
    (i) Prior to the accumulation of 14,000 total flight hours or 
2,250 total flight cycles, whichever occurs first.
    (ii) Within 6 months after the effective date of this AD.

Action if No Cracking Is Found

    (h) If no cracking is found during any inspection required by 
paragraph (g) of this AD: Before further flight, apply sealant and a 
torque stripe and install a lockwire on the rudder PCM in accordance 
with the Accomplishment Instructions, and Figure 1

[[Page 13483]]

or Figure 2, as applicable, of Boeing Service Bulletin 747-27A2397, 
Revision 2, dated September 1, 2005.

Action if Cracking Is Found

    (i) If any cracking is found during any inspection required by 
paragraph (g) of this AD: Before further flight, do the action in 
paragraph (i)(1) or (i)(2) of this AD.
    (1) Replace the affected PCM with a new or serviceable PCM in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-27A2397, Revision 2, dated September 1, 2005.
    (2) Replace the PCM with a PCM that has the new secondary 
retention device installed as specified in paragraph (j) of this AD.

Terminating Action

    (j) Within 24 months or 8,400 flight hours after the effective 
date of this AD, whichever occurs earlier: Install a new secondary 
retention device for the yaw damper piston assembly in both the 
upper and lower PCMs by either replacing the existing PCM with a new 
improved PCM that already has the new secondary retention device, or 
by modifying, testing, and re-identifying the existing PCM. Do the 
installation in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 747-27A2479, dated November 8, 2007. 
Doing the installation terminates the inspection requirements of 
this AD.

    Note 1: Boeing Alert Service Bulletin 747-27A2479 refers to 
Parker Service Bulletins 332700-27-312 and 333200-27-314, both dated 
September 13, 2007, as additional sources of service information for 
modifying the PCM.

Prior Accomplishment of Requirements

    (k) Actions accomplished before October 13, 2006 (the effective 
date of AD 2006-18-17), in accordance with Boeing Alert Service 
Bulletin 747-27A2397, dated July 24, 2003; or Revision 1, dated 
March 31, 2005; are considered acceptable for compliance with the 
corresponding requirements of this AD.

Parts Installation

    (l) As of October 13, 2006 no person may install on any airplane 
a rudder PCM having a top assembly part number (P/N) 332700-1003, -
1005, or -1007; or P/N 333200-1003, -1005, or -1007; unless the PCM 
has been ultrasonically inspected and found to be without cracks; in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-27A2397, Revision 2, dated September 1, 2005, as 
specified by paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

    (m)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested in 
accordance with 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) AMOCs approved previously in accordance with AD 2006-18-17 
are approved as AMOCs for the corresponding provisions of paragraphs 
(g), (h), and (i) of this AD.

    Issued in Renton, Washington, on March 4, 2008.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-5013 Filed 3-12-08; 8:45 am]

BILLING CODE 4910-13-P
