AD 2001-12-21

[Federal Register Volume 66, Number 120 (Thursday, June 21, 2001)]
[Rules and Regulations]
[Pages 33170-33173]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-15569]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-158-AD; Amendment 39-12277; AD 2001-12-21]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes 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. 
For certain airplanes, this amendment requires installation of improved 
fuel pumps, which terminates the requirements of the existing AD. This 
amendment is prompted by new information received from the fuel pump 
manufacturer. The actions specified by this 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: Effective July 26, 2001.

ADDRESSES: Information pertaining to this AD may be examined at the 
Federal Aviation Administration (FAA), Transport Airplane Directorate, 
Rules Docket, 1601 Lind Avenue, SW., Renton, Washington.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 98-25-52, 
amendment 39-10957 (63 FR 71214, December 24, 1998), which is 
applicable to all Boeing Model 747 series airplanes, was published in 
the Federal Register on November 20, 2000 (65 FR 69718). The action 
proposed to require, for certain airplanes, installation of improved 
fuel pumps, which would terminate the requirements of the existing AD.

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.

Clarify Intent of Paragraph (b)

    One commenter requests that the FAA revise paragraph (b) of the 
proposed rule to clarify that compliance with the requirements of that 
paragraph terminates the requirements of paragraph (a) of the proposed 
rule. The commenter points out that, while paragraph (b) states that no 
further action is required if it is determined that the correct thrust 
washer is installed under the guidelines in paragraphs (b)(1), (b)(2), 
and (b)(3) of the proposed rule, paragraph (b) does not state that the 
operational limitations in paragraph (a) are no longer necessary.

[[Page 33171]]

    The FAA concurs with the commenter's request, and has revised 
paragraph (b) of this AD to state that accomplishment of that paragraph 
terminates the requirements of paragraph (a) of this AD.

Revise Paragraph (b) to Reference Acceptable Parts

    One commenter requests that the FAA revise paragraph (b) to refer 
to the acceptable replacement parts identified in paragraph (c) of the 
proposed rule. The commenter states that Crane Hydro-Aire fuel pumps 
having thrust washers, part number 60-06561, with a date code of 9848 
or higher etched on the outside diameter of the thrust washer, are 
acceptable. If such pumps are installed, no further action is required 
by this AD; thus, this guideline should be included with the others 
under paragraph (b). The commenter notes that this change will make the 
proposed rule easier to follow.
    The FAA concurs, and has added a new paragraph (b)(4) to this final 
rule.

Revise Cost Impact

    One commenter, the parts manufacturer, requests that the FAA revise 
the ``Cost Impact'' section of the proposed rule to remove the 
statement ``Required parts would be provided by the manufacturer at no 
cost to the operators.'' The commenter states that there are certain 
restrictions on the cost of parts to the operators, based on the date 
of overhaul or repair of the pumps. The commenter suggests including a 
new statement such as, ``Modification of the fuel pump by CRANE Hydro-
Aire or required parts for modification by the operator will be 
provided by the manufacturer'at no cost to the operator in accordance 
with the ``Repair Options'' and ``Warranty'' sections of the applicable 
CRANE Hydro-Aire Service Bulletin.''
    The FAA concurs with the intent of the commenter's request. The FAA 
has revised the ``Cost Impact'' section of this final rule to include 
the following statement, which is more general than the statement 
suggested by the commenter: ``The parts manufacturer has committed 
previously to its customers that it may bear the cost of replacement 
parts with certain restrictions, based on the date of overhaul or 
repair of the pumps.''

Limit Applicability

    One commenter, the airplane manufacturer, requests that the FAA 
revise the proposed rule to limit the applicability to airplanes up to 
and including line number 1188. The commenter states that airplanes 
after line number 1188 have the correct thrust washers installed and, 
therefore, are not subject to the actions in the proposed rule. The 
commenter further notes that in-service pump replacements on airplanes 
after line number 1188 will be maintained by normal operator practices 
for parts control.
    The FAA does not concur with the commenter's request to limit the 
applicability. Though only certain airplanes were produced with the 
incorrect thrust washer, the pump with the subject washer may easily be 
removed from one airplane and installed on another airplane. Thus, 
airplanes such as those with line numbers 1188 and subsequent, which 
were delivered with the correct thrust washer, may subsequently have 
had a pump with a discrepant thrust washer installed. No change to the 
final rule is necessary in this regard.

Request To Clarify Compliance Tracking

    One commenter requests that paragraph (b) of the proposed rule be 
revised to specifically reference the accomplishment instructions of 
Boeing Service Bulletin 747-28-2225, dated December 3, 1998. Paragraph 
(b) defines conditions under which no action is required per this AD. 
The commenter states that including a reference to Boeing Service 
Bulletin 747-28-2225 would make it easier for operators to track 
compliance for the purposes of this proposed rule.
    The FAA does not concur with the commenter's request. The FAA finds 
that compliance may be tracked by the part number of the override or 
override/jettison pump, or by review of maintenance records, methods 
which are allowed by paragraph (b) of this AD. The FAA finds that 
revising paragraph (b) of this AD in the manner suggested by the 
commenter would provide no improvement in the clarity of the AD. 
However, the original issue of Boeing Service Bulletin 747-28-2225, as 
well as Revision 3, dated March 3, 1999, were previously approved as 
alternative methods of compliance (AMOCs) for AD 98-25-52. Accordingly, 
paragraph (d)(2) of this AD, states that (with one exception) AMOCs 
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. Airplanes on which the intent of paragraph (a) of this AD has 
been accomplished are not subject to paragraph (b) of this AD. Thus, no 
change to the final rule is necessary in this regard.

Comment on Implied Life Limit of Thrust Washer

    One commenter notes that the following statement, made in the 
``Actions Since Issuance of Previous Rule'' section of the proposed 
rule, indicates that the life of the thrust washer on the improved 
pumps has been extended from 500 hours to ``more than 15,000 hours.'' 
The commenter expresses concern that, while this may be a significant 
improvement in life limit, failure of the pump, whether at 15,000 hours 
or 500 hours, would still be catastrophic and, thus, is an unacceptable 
risk. The commenter states that, if the failure mode is still present 
in the improved pump, the commenter would not support the removal of 
the fuel quantity restrictions from the Airplane Flight Manual as 
allowed by the proposed rule.
    The FAA infers that the commenter is requesting that the FAA remove 
the terminating action provided by paragraph (c) of this AD. The FAA 
does not concur with the commenter's request. The statement noted by 
the commenter was intended as a reference, not to indicate that the 
life of the thrust washer was 15,000 hours. Service experience has 
shown that the aluminum oxide coating applied to the thrust washer 
using a D-gun spray method lasts at least as long as the currently 
expected service life of the pump between overhauls. While no specific 
limit on the overhaul interval for the pump exists, the FAA has 
determined that an acceptable level of safety will be provided with 
respect to failure of the thrust bearing without continuing to require 
the AFM procedures for early pump shutoff. However, the FAA recognizes 
and agrees with the commenter's concern regarding the possible failure 
modes of fuel pumps and the current design practice of routinely 
allowing fuel pumps in auxiliary fuel tanks (including built-in 
auxiliary tanks such as the center wing tank and the horizontal 
stabilizer tank on Model 747-400 series airplanes) to run until the 
inlets are uncovered. The FAA is examining this issue and is 
considering issuing additional rulemaking to address fuel pump 
installations that are not fail-safe on existing transport airplane 
designs. No change to the final rule is necessary in this regard.

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 changes

[[Page 33172]]

previously described. The FAA has determined that these changes will 
neither increase the economic burden on any operator nor increase the 
scope of the 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 will be affected by this 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 required for certain airplanes by this new AD will 
take approximately 25 work hours per airplane to accomplish, at an 
average labor rate of $60 per work hour. The parts manufacturer has 
committed previously to its customers that it may bear the cost of 
replacement parts with certain restrictions, based on the date of 
overhaul or repair of the pumps. Based on these figures, the cost 
impact of the 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 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, 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 removing amendment 39-10957 (63 FR 
71214, December 24, 1998), and by adding a new airworthiness directive 
(AD), amendment 39-12277, to read as follows:

2001-12-21  Boeing: Amendment 39-12277. 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:

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: 
If all pumps meet the criteria

[[Page 33173]]

specified in paragraph (b)(1), (b)(2), (b)(3), or (b)(4) of this AD 
(i.e., the correct thrust washer is installed), no further action is 
required by this AD. Accomplishment of this paragraph terminates the 
requirements of paragraph (a) of 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.
    (4) For airplanes having 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, 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), (b)(3), or (b)(4) 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), AMOCs 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.

Effective Date

    (f) This amendment becomes effective on July 26, 2001.

    Issued in Renton, Washington, on June 14, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-15569 Filed 6-20-01; 8:45 am]
BILLING CODE 4910-13-P