[Federal Register Volume 65, Number 224 (Monday, November 20, 2000)]
[Proposed Rules]
[Pages 69718-69720]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-29498]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 65, No. 224 / Monday, November 20, 2000 / 
Proposed Rules  

[[Page 69718]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-158-AD]
RIN 2120-AA64


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 supersedure of an existing 
airworthiness directive (AD), applicable to all Boeing Model 747 series 
airplanes, that currently requires revising the Airplane Flight Manual 
to include procedures to prevent dry operation of the center wing fuel 
tank override/jettison pumps and, for certain airplanes, to prohibit 
operation of the horizontal stabilizer tank transfer pumps in-flight. 
That AD was prompted by a report indicating that several override/
jettison fuel pumps from the center wing tanks and main tanks had been 
removed because circuit breakers for the override/jettison fuel pumps 
were tripped, or low pump output pressure was indicated. For certain 
airplanes, this action would require installation of improved fuel 
pumps, which would terminate the requirements of the existing AD. This 
proposal is prompted by new information received from the fuel pump 
manufacturer. The actions specified by the proposed AD are intended to 
prevent contact between the rotating paddle wheel and the stationary 
end plates within the center wing tank override/jettison fuel pumps or 
horizontal stabilizer tank transfer pumps, which could cause sparks 
and/or a hot surface condition and consequent ignition of fuel vapor in 
the center wing tank or horizontal stabilizer tank during dry pump 
operation (no fuel flowing).

DATES: Comments must be received by January 4, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-158-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. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-158-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.

FOR FURTHER INFORMATION CONTACT: Sulmo Mariano, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2686; fax (425) 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 action may be changed in 
light of the comments received.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-158-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-114, Attention: Rules 
Docket No. 2000-NM-158-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On December 15, 1998, the FAA issued AD 98-25-52, amendment 39-
10957 (63 FR 71214, December 24, 1998), applicable to all Boeing Model 
747 series airplanes, to require revising the Airplane Flight Manual to 
include procedures to prevent dry operation of the center wing fuel 
tank override/jettison pumps and, for certain airplanes, to prohibit 
operation of the horizontal stabilizer tank transfer pumps in-flight. 
That action was prompted by a report indicating that several override/
jettison fuel pumps from the center wing tanks and main tanks had been 
removed because circuit breakers for the override/jettison fuel pumps 
were tripped, or low pump output pressure was indicated. The 
requirements of that AD are intended to prevent contact between the 
rotating paddle wheel and the stationary end plates within the center 
wing tank override/jettison fuel pumps or horizontal stabilizer tank 
transfer pumps due to excessive wear of the pump shaft carbon thrust 
bearing, which could cause sparks and/or a hot surface condition and 
consequent ignition of fuel vapor in the center wing tank or horizontal 
stabilizer tank during dry pump operation (no fuel flowing).

[[Page 69719]]

Actions Since Issuance of Previous Rule

    In the preamble to AD 98-25-52, the FAA indicated that the actions 
required by that AD were considered ``interim action'' and that further 
rulemaking action was being considered. The FAA now has determined that 
further rulemaking action is indeed necessary, and this proposed AD 
follows from that determination.
    Since the issuance of AD 98-25-52, the FAA has received information 
from the fuel pump manufacturer indicating that it has now determined 
the cause of the premature wear of the thrust carbon bearings of the 
center wing tank override/jettison fuel pumps, and the horizontal 
stabilizer tank transfer pumps. The thrust washer located in the pump 
shaft thrust bearing was coated with aluminum oxide, applied using a 
plasma spray method, and investigation revealed that this method has a 
life limit of less than 500 flight hours. Further investigation 
revealed that aluminum oxide coating applied to the thrust washer using 
a D-gun spray method has a life limit of more than 15,000 flight hours.
    During operation at normal fuel pump rotation speeds (7,000 to 
8,000 RPM), the steel-to-steel contact may produce sparks or hot spots 
sufficient to ignite fuel vapor from the center wing tank or horizontal 
stabilizer tank, when the pump is running dry. The center wing fuel 
tank pumps on 747-400 series airplanes are normally operated until the 
fuel in the tank is exhausted and the pump inlet is uncovered, exposing 
the fuel pump to dry or partially dry operation for a period of time 
during each flight when the center wing tank is used. The horizontal 
stabilizer tank on 747-400 series airplanes uses the same pumps and is 
also run out dry each time it is used. Replacement of the existing 
pumps with improved pumps having the correct thrust washers installed 
enhances airplane safety in that it eliminates the possibility that 
pumps with bad washers will be operated when the pump is running dry.

Explanation of Requirements of Proposed Rule

    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 supersede AD 98-25-52 to continue to require revising 
the Airplane Flight Manual to include procedures to prevent dry 
operation of the center wing fuel tank override/jettison pumps and, for 
certain airplanes, to prohibit operation of the horizontal stabilizer 
tank transfer pumps in-flight. For certain airplanes, the proposed AD 
also would require the installation of improved fuel pumps, which would 
terminate the requirements of the existing AD.

Cost Impact

    There are approximately 1,100 Model 747 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 250 
airplanes of U.S. registry would be affected by this proposed AD.
    The AFM revisions that are currently required by AD 98-25-52 take 
approximately 1 work hour per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the currently required actions on U.S. operators is estimated 
to be $15,000, or $60 per airplane.
    The replacements that are proposed in this new AD action would take 
approximately 25 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would be provided by 
the manufacturer at no cost to the operators. Based on these figures, 
the cost impact of the proposed requirements of this AD on U.S. 
operators is estimated to be $375,000, or $1,500 per airplane.
    The cost impact figures discussed above are 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 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 proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-10957 (63 FR 
71214, December 24, 1998), and by adding a new airworthiness directive 
(AD), to read as follows:

 Boeing: Docket 2000-NM-158-AD. Supersedes AD 98-25-52, amendment 
39-10957.

    Applicability: All Model 747 series airplanes, 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 (d)(1) 
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 contact between the rotating paddle wheel and the 
stationary end plates within the center wing tank override/jettison 
fuel pumps or horizontal stabilizer tank transfer pumps due to 
excessive wear of the pump shaft carbon thrust bearing, which can 
cause sparks and/or a hot surface condition and consequent ignition 
of fuel vapor in the center wing tank or horizontal stabilizer tank 
during dry pump operation (no fuel flowing), accomplish the 
following:

[[Page 69720]]

Restatement of Requirements of AD 98-25-52

Airplane Flight Manual (AFM) Revisions

    (a) Within 7 days after December 29, 1998 (the effective date of 
AD 98-25-52, amendment 39-10957), revise the Limitations Section of 
the FAA-approved AFM to include the following procedures. This may 
be accomplished by inserting a copy of this AD into the AFM.
    ``For Model 747-400 series airplanes equipped with a horizontal 
stabilizer tank, operation of the horizontal stabilizer tank 
transfer pumps is prohibited in flight.
    A tripped circuit breaker of a center wing tank override/
jettison pump or a tripped circuit breaker of a horizontal 
stabilizer tank transfer pump must not be reset until the associated 
fuel pump has been inspected for damage and any damage has been 
repaired.
    The center wing tank override/jettison pumps must be operated in 
accordance with either option 1 or option 2 below.

Option 1

    If the center wing tank override/jettison pumps are required for 
flight, the center tank must contain a minimum of 17,000 pounds 
(7,700 kilograms) at engine start. The fuel quantity indicating 
system of the center wing tank must be operative to dispatch with 
center wing tank fuel intended for use in the flight.
    Select both center wing tank override/jettison pump switches off 
at or before the fuel quantity of the center wing tank reaches 7,000 
pounds (3,200 kilograms). Note: On Model 747-400 series airplanes, 
the ``FUEL OVRD CTR L'' and ``FUEL OVRD CTR R'' engine indication 
and crew alerting system (EICAS) messages will be displayed with the 
switches off.
    The center wing tank override/jettison pumps may be operated 
with less than 7,000 pounds of fuel in the center wing tank if 
required to address an emergency (such as fuel jettison or low fuel 
quantity).

Option 2

    If the center wing tank override/jettison pumps are required for 
flight, the center tank must contain a minimum of 50,000 pounds 
(22,700 kilograms) at engine start. The fuel quantity indicating 
system of the center wing tank must be operative to dispatch with 
center wing tank fuel intended for use in the flight.
    Select both center wing tank override/jettison pump switches off 
at or before center wing tank fuel quantity reaches 3,000 pounds 
(1,400 kilograms).
    The center wing tank override/jettison pumps may be operated 
with less than 3,000 pounds of fuel in the center wing tank if 
required to address an emergency (such as fuel jettison or low fuel 
quantity).''

New Requirements of This AD

Determination of Correct Thrust Washer

    (b) For airplanes having center wing fuel tank override/jettison 
pumps and, if installed, horizontal stabilizer tank transfer pumps, 
and all pumps meet the criteria specified in paragraph (b)(1), 
(b)(2), or (b)(3) of this AD (i.e., the correct thrust washer is 
installed), no further action is required by this AD.
    (1) Verify the serial number on the pump data plate. The first 
four digits of the pump serial number represent the month and year 
of manufacture (e.g., 0697 indicates a pump manufactured in June 
1997). If the serial number date code indicates that the pump was 
manufactured prior to July 1996, or after November 1998, and if the 
operator can determine that the pump was not overhauled or repaired 
after July 31, 1996, then the pump has the correct thrust washer 
installed. If the pump was overhauled or repaired after July 31, 
1996, and the operator has maintenance/overhaul records showing that 
the thrust washer was not replaced, or was replaced with the correct 
thrust washer, as specified in paragraph (c) of this AD, then the 
pump has the correct thrust washer installed.
    (2) For airplanes having a date of manufacture prior to July 
1996, if the operator can determine that the pump was not overhauled 
or repaired after July 31, 1996; and the pump was not replaced with 
a new pump manufactured between July 1996 and November 1998, then 
the pump has the correct thrust washer installed. If the pump was 
overhauled or repaired after July 31, 1996, and the operator has 
maintenance/overhaul records showing that the thrust washer was not 
replaced, or was replaced with the correct thrust washer, as 
specified in paragraph (c) of this AD, then the pump has the correct 
thrust washer installed.
    (3) For airplanes having pumps installed containing a serial 
number on the pump data plate with the suffix ``P,'' the pump has 
the correct thrust washer installed.

Terminating Action

    (c) For airplanes that do not meet the requirements specified in 
paragraph (b)(1), (b)(2), or (b)(3) of this AD; or if the serial 
number on the pump data plate of any fuel pump cannot be determined: 
Within 24 months after the effective date of this AD, replace the 
applicable center wing fuel tank override/jettison pumps and 
horizontal stabilizer tank transfer pumps with Crane Hydro-Aire fuel 
pumps having a thrust washer, part number 60-06561, with a date code 
of 9848 (``98'' indicates the year 1998, and ``48'' indicates the 
48th week in 1998), or higher, etched on the outside diameter of the 
thrust washer. Accomplishment of this paragraph terminates the 
requirements of paragraph (a) of this AD.

Alternative Methods of Compliance

    (d)(1) An alternative method of compliance (AMOC) 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 Operations Inspector 
or Principal Maintenance Inspector, as applicable, who may add 
comments and then send it to the Manager, Seattle ACO.
    (2) With the exception of FAA AMOC letter to Boeing (No. 98-140-
437, dated December 9, 1998), AMOC's approved previously in 
accordance with AD 98-25-52, amendment 39-10957, are approved as 
alternative methods of compliance with paragraph (a) of this AD.

    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 Permits

    (e) 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 November 13, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-29498 Filed 11-17-00; 8:45 am]
BILLING CODE 4910-13-P