[Federal Register Volume 61, Number 158 (Wednesday, August 14, 1996)]
[Proposed Rules]
[Pages 42195-42197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-20671]


 ========================================================================
 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. 61, No. 158 / Wednesday, August 14, 1996 / 
Proposed Rules  

[[Page 42195]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-57-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 and 757 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 all Boeing Model 747 and 757 
series airplanes. This proposal would require repetitive visual 
inspections to detect discrepancies of the wire terminal assembly, 
electrical connector, and wire insulation on the fuel pump; and 
replacement of the fuel pump with a new fuel pump, if necessary. The 
proposed AD also would require repetitive insulation resistance tests 
of the fuel pump wiring. This proposal is prompted by reports of fuel 
leaks at the fuel boost and override/jettison pumps due to corrosion. 
The actions specified by the proposed AD are intended to prevent such a 
fuel leakage, which could result in a fire at the location of the 
affected fuel pump.

DATES: Comments must be received by September 16, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-57-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. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: G. Michael Collins, Aerospace 
Engineer, Seattle Aircraft Certification Office, Propulsion Branch, 
ANM-140S, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056; telephone (206) 227-2689; 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 96-NM-57-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. 96-NM-57-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received several reports of fuel leaks at the fuel 
boost and override/jettison pumps on Boeing Model 747 series airplanes. 
As a result of these incidents, the fuel pumps were removed from these 
airplanes. These pumps had accumulated between 34,000 to 67,000 total 
hours since new or since overhaul.
    Analyses of the removed pumps revealed that moisture ingression 
around the potting of the wire terminal assembly can cause corrosion in 
the wire terminal assembly. (Variation in the manufacturing of the 
connectors and exposure of an airplane to different operational 
environments can affect the time required to form the corrosion.) Such 
corrosion can lead to electrical arcing between the power pins and the 
pump case. The arcing could then cause deterioration of the terminal 
pins and thermal expansion of the material inside the cap. Thermal 
expansion can cause failure of the cap attachment flange or attaching 
screws, and, consequently lead to a fuel leak. A high current during 
arcing also could melt a hole through the end case and connector of the 
fuel pump, which also could result in a fuel leak.
    Fuel leakage at the fuel boost and override/jettison pumps, if not 
detected and corrected, could result in a fire at the location of the 
affected fuel pump.
    The fuel boost and override/jettison pumps of Model 747 series 
airplanes are similar in design to those of Model 757 series airplanes. 
Therefore, the FAA has determined that Model 757 series airplanes may 
be subject to the same fuel leakage problem.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Service Bulletin 747-
28A2194, Revision 1, dated January 18, 1996 (for Model 747 series 
airplanes), and Boeing Service Bulletin 757-28A0043, Revision 1, dated 
January 18, 1996 (for Model 757 series airplanes). These service 
bulletins describe procedures for repetitive visual inspections to 
detect discrepancies (i.e., fuel leak, heat discoloration, and damage) 
of the wire terminal assembly, electrical connector, and wire 
insulation on the fuel pump; and replacement of the fuel pump with a 
new fuel pump, if necessary. These service bulletins also describe 
procedures for repetitive insulation resistance tests of the fuel pump 
wiring.

[[Page 42196]]

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 require a visual inspection to detect discrepancies 
of the wire terminal assembly, electrical connector, and wire 
insulation on the fuel pump; and replacement of the fuel pump with a 
new fuel pump, if necessary. The proposed AD also would require 
repetitive insulation resistance tests of the fuel pump wiring. The 
actions would be required to be accomplished in accordance with the 
service bulletins described previously.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Cost Impact

    There are approximately 1,084 Model 747 series airplanes and 716 
Model 757 series airplanes of the affected design in the worldwide 
fleet. Of these airplanes, 242 Model 747 series airplanes and 462 Model 
757 series airplanes are of U.S. registry and would be affected by this 
proposed AD.
    For 242 Model 747 series airplanes, it would take approximately 18 
work hours per airplane to accomplish the proposed actions, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators of Model 747 series 
airplanes is estimated to be $261,360, or $1,080 per airplane.
    For the 462 Model 757 series airplanes, it would take approximately 
12 work hours per airplane to accomplish the proposed actions, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators of Model 757 series 
airplanes is estimated to be $332,640, or $720 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.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

Boeing: Docket 96-NM-57-AD.

    Applicability: All Model 747 and 757 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 (c) 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 fuel leakage at the fuel boost and override/jettison 
pumps, which could result in a fire at the location of the affected 
fuel pump, accomplish the following:
    (a) Within 120 days after the effective date of this AD, perform 
a visual inspection to detect discrepancies (i.e., fuel leak, heat 
discoloration, and damage) of the wire terminal assembly, electrical 
connector, and wire insulation on the fuel pump, in accordance with 
Boeing Service Bulletin 747-28A2194, Revision 1, dated January 18, 
1996 (for Model 747 series airplanes), or Boeing Service Bulletin 
757-28A0043, Revision 1, dated January 18, 1996 (for Model 757 
series airplanes), as applicable.
    (1) If no discrepancy is detected, prior to further flight, 
perform an insulation resistance test of the fuel pump wiring, in 
accordance with the Accomplishment Instructions of the applicable 
service bulletin.
    (i) If any resistance measurement is less than or equal to 1 
megohms, prior to further flight, replace the fuel pump with a new 
fuel pump, in accordance with the applicable service bulletin. Prior 
to further flight following accomplishment of the replacement, 
repeat the insulation resistance test.
    (ii) If any resistance measurement is greater than 1 megohms but 
less than 5 megohms: Repeat the visual inspection and insulation 
resistance test within 500 hours, or replace the fuel pump with a 
new fuel pump. Prior to further flight following accomplishment of 
the replacement, repeat the insulation resistance test.
    (iii) If any resistance measurement is greater than or equal to 
5 megohms, repeat the visual inspection and insulation resistance 
test within 5,000 hours or 18 months, whichever occur first.
    (2) If any discrepancy is detected, prior to further flight, 
replace the fuel pump with a new fuel pump, in accordance with the 
applicable service bulletin. Prior to further flight following 
accomplishment of the replacement, perform an insulation resistance 
test of the fuel pump wiring, in accordance with the Accomplishment 
Instructions of the applicable service bulletin.
    (i) If any resistance measurement is less than or equal to 1 
megohms, prior to further flight, replace the fuel pump with a new 
fuel pump, in accordance with the applicable service bulletin. Prior 
to further flight following accomplishment of the replacement, 
repeat the insulation resistance test.
    (ii) If any resistance measurement is greater than 1 megohms but 
less than 5 megohms: Repeat the visual inspection and insulation 
resistance test within 500 hours, or replace the fuel pump with a 
new fuel pump. Prior to further flight following accomplishment of 
the replacement, repeat the insulation resistance test.
    (iii) If any resistance measurement is greater than or equal to 
5 megohms, repeat the visual inspection and insulation resistance 
test within 5,000 hours or 18 months, whichever occur first.
    (b) Within 10 days after accomplishing the initial visual 
inspection required by paragraph (a) of this AD, submit a report of 
the inspection results (both positive and

[[Page 42197]]

negative findings) to the Manager, Seattle Aircraft Certification 
Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 
telephone (206) 227-2689; fax (206) 227-1181. Information collection 
requirements contained in this regulation have been approved by the 
Office of Management and Budget (OMB) under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have 
been assigned OMB Control Number 2120-0056.
    (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), FAA, 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.

    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 August 7, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-20671 Filed 8-13-96; 12:33 pm]
BILLING CODE 4910-13-U