[Federal Register Volume 60, Number 42 (Friday, March 3, 1995)]
[Proposed Rules]
[Pages 11942-11944]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-5244]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-226-AD]


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747 series 
airplanes. This proposal would require modification of the left and 
right inboard elevator servo assemblies and the hydraulic routing of 
the right inboard elevator power control package (PCP). This proposal 
is prompted by a report of an uncommanded right elevator deflection 
after takeoff and reports of elevator/control column bumps during 
landing gear retraction on these airplanes. The actions specified by 
the proposed AD are intended to prevent uncommanded elevator 
deflection, which could result in structural damage and reduced 
controllability of the airplane.

DATES: Comments must be received by April 28, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-226-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207; and Parker Hannifin Corporation, Customer 
Support Operations, 16666 Von Karman Avenue, Irvine, California 92714. 
This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Kathi N. Ishimaru, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (206) 227-2674; fax (206) 
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 notice may be changed in 
light of the comments received.
    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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-226-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-103, Attention: Rules 
Docket No. 94-NM-226-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received one report of an uncommanded right elevator 
deflection after takeoff and two reports of elevator/control column 
bumps during landing gear retraction on Boeing Model 747-400 series 
airplanes equipped with certain inboard elevator Parker power control 
packages (PCP). Investigation revealed that hydraulic system number 4 
is connected to the sensitive side of the servo valve, which may lead 
to an uncommanded elevator motion when the return pressure for the 
hydraulic system number 4 fluctuates. This condition, if not corrected, 
could result in structural damage and reduced controllability of the 
airplane.
    The FAA has reviewed and approved Parker Service Bulletin 327400-
27-171, dated December 2, 1994, which describes procedures for 
modification of [[Page 11943]] the left and right servo assemblies of 
the PCP of the inboard elevator for Model 747-100, -200, -300, and -400 
series airplanes, equipped with certain Parker PCP's. The modification 
involves rework of the dual tandem servo assembly. This modification 
will prevent blockage of the hydraulic balance passageway by the spring 
guide, which can contribute to the uncommanded motion of the PCP.
    However, for certain Model 747-400 series airplanes, Boeing has 
issued Alert Service Bulletin 747-27A2348, Revision 1, January 26, 
1995, which describes additional procedures for modification of the 
hydraulic tubing of the right inboard elevator PCP. This modification 
connects the hydraulic system number 3 to the sensitive side of the 
servo valve. This modification will prevent an uncommanded right 
elevator deflection caused by hyraulic system number 4 pressure 
flucuations. The FAA has reviewed and approved this alert service 
bulletin.-
    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 modification of the left and right servo 
assemblies and re-routing the hydraulic tubing of the inboard elevator 
PCP. The actions would be required to be accomplished in accordance 
with the service bulletins described previously. -
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this long-standing requirement. 
-
    There are approximately 672 Model 747-100, -200, and -300 series 
airplanes, and 357 Model 747-400 series airplanes of the affected 
design in the worldwide fleet, a total of 1,000 airplanes. -
    The FAA estimates that 114 Model 747-100, -200, and -300 series 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 73 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $60 per work 
hour. Required parts would cost approximately $3,720 per airplane. 
Based on these figures, the total cost impact of the proposed AD on 
U.S. operators is estimated to be $923,400, or $8,100 per airplane. -
    The FAA estimates that 65 Model 747-400 series airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 111 work hours per airplane to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would cost approximately $8,549 per airplane. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $988,585, or $15,209 per airplane. -
    The total 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 AD were not adopted. -
    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment. -
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended] -

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 94-NM-226-AD.

     -Applicability: Model 747-100, -200, -300, and -400 series 
airplanes, equipped with Parker inboard elevator power control 
packages (PCP) having part numbers (P/N) 327400-1001, -1003, -1005, 
and -1007; 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 use the authority 
provided in paragraph (c) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

     -Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent uncommanded elevator deflection, which could result 
in structural damage and reduced controllability of the airplane, 
accomplish the following: -
    (a) For Model 747-400 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-27A2348, dated November 17, 1994: Within 
1 year after the effective date of this AD, modify the hydraulic 
tubing of the right inboard elevator PCP, in accordance with Boeing 
Alert Service Bulletin 747-27A2348, Revision 1, dated January 26, 
1995. -
    (b) For all airplanes: Within 3 years after the effective date 
of this AD, modify the left and right servo assemblies of the 
inboard elevator PCP, in accordance with Parker Service Bulletin 
327400-27-171, dated December 2, 1994. -
    (c) 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), ANM-100S, Transport Airplane Directorate. 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.

    - [[Page 11944]] Note 2: Information concerning the existence of 
approved alternative methods of compliance with this AD, if any, may 
be obtained from the Seattle ACO.

     -(d) 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 February 27, 1995.

Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-5244 Filed 3-2-95; 8:45 am]
BILLING CODE 4910-13-U