AD 2002-10-02

[Federal Register Volume 67, Number 95 (Thursday, May 16, 2002)]
[Rules and Regulations]
[Pages 34820-34822]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-12065]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-414-AD; Amendment 39-12748; AD 2002-10-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 757 series airplanes, that requires 
installation of an extender bracket for the compensator of the Simmonds 
fuel quantity indication system (FQIS) in the main fuel tanks. This 
action is necessary to prevent contact between the compensator for the 
Simmonds FQIS system and a flapper check valve on a baffle rib in the 
main fuel tanks, which--in conjunction with another wiring failure 
outside the fuel tank--could result in an electrical arc and a 
consequent potential source of ignition in the fuel tank. This action 
is intended to address the identified unsafe condition.

DATES: Effective June 20, 2002.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 20, 2002.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: John Vann, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-1024; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 757 series 
airplanes was published in the Federal Register on October 24, 2001 (66 
FR 53743). That action proposed to require installation of an extender 
bracket for the compensator of the Simmonds fuel quantity indication 
system (FQIS) in the main fuel tanks.

Explanation of New Relevant Service Information

    Since the issuance of the proposed AD, the FAA has reviewed and 
approved Boeing Service Bulletins 757-28-0057 and 757-28-0059, both 
Revision 1, both dated February 28, 2002. (The proposed AD refers to 
Boeing Special Attention Service Bulletins 757-28-0057 and 757-28-0059, 
both dated September 14, 2000, as the appropriate sources of service 
information for the proposed actions.) We find that the changes 
incorporated in Revision 1 of the service bulletins are not 
substantive, meaning that airplanes modified per the original issue of 
the service bulletins are not subject to any additional work under 
Revision 1 of the service bulletins. Therefore, the FAA has revised 
paragraph (a) of this final rule to refer to Revision 1 of the service 
bulletins as the appropriate sources of service information for the 
actions in that paragraph. In addition, we have added a new Note 2 (and 
reordered subsequent notes accordingly) to give credit for 
installations accomplished before the effective date of this AD 
according to the original issue of the service bulletins. Also, because 
no additional airplanes were included in the effectivity listing of the 
revised service bulletins, and for the convenience of operators, we 
have revised the applicability statement of this final rule to refer to 
airplanes listed in Revision 1 of the service bulletins.

[[Page 34821]]

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.

Request To Extend the Compliance Time

    One commenter, an operator, asks us to extend the compliance time 
for the proposed AD from 24 to 48 months. The commenter notes that the 
proposed actions necessitate defueling, purging, and opening the wing 
fuel tanks. Such actions are classified as heavy maintenance and, thus, 
would normally only be performed during a heavy maintenance visit 
(e.g., a heavy ``C''-check). The commenter notes that the interval for 
such a check for its fleet is approximately 48 months. This commenter 
believes that allowing the proposed actions to be accomplished at a 
normal heavy maintenance visit would not significantly decrease the 
level of safety, and notes that allowing such a schedule would enable 
operators to avoid significant out-of-service time and labor costs.
    The FAA concurs with the commenter's request. We note that 
extending the compliance time to 48 months results in a longer 
compliance time than allowed in other ADs related to possible ignition 
in the fuel tank. However, our decision is based on the fact that a 
condition in which the compensator of the Simmonds FQIS is exposed to 
fuel vapors, the flapper valve is in contact with the compensator, and 
a wiring failure occurs outside the fuel tank, is expected to be rare. 
The compensator is only exposed to flammable vapors when the quantity 
of fuel is low, and the flapper valve would have to be lifted open 
significantly to come into contact with the compensator. Furthermore, 
we recognize that there are safety benefits to limiting the number of 
entries into the fuel tank, and the longer compliance time may allow 
operators to combine the required modification with other fuel tank 
maintenance. Therefore, we find that increasing the compliance time for 
this AD from 24 months to 48 months does not significantly decrease the 
level of safety. We have revised paragraph (a) of this final rule 
accordingly.

Request To Reduce Compliance Time

    One commenter asks us to reduce the compliance time for the 
requirements of the proposed AD from 24 months to 12 months or less. 
The commenter notes that the proposed AD identifies an electrical arc 
associated with an external wiring fault as the only potential source 
of ignition. However, the commenter would like it to be noted that a 
lightning-induced transient on the fuel compensator wiring may 
represent another source of ignition. The commenter states that current 
data show the probability of a lightning strike on an aircraft as one 
strike per aircraft per year. The commenter's suggestion to reduce the 
compliance time for the proposed AD is based on this probability.
    We do not concur to reduce the compliance time. While we agree that 
lightning strikes can induce a transient on the fuel compensator 
wiring, a lightning strike on its own is unlikely to be a potential 
source of ignition in the fuel tank. For a lightning strike to be a 
threat, two additional conditions must be present. First, as noted 
previously, the compensator for the Simmonds FQIS, which is normally 
covered by fuel, would have to be exposed to fuel vapor; this could 
only occur at a low-fuel state. Second, there would have to be 
electrical contact between the Simmonds FQIS and the flapper valve 
referred to in the referenced service bulletins. We find that the 
possibility of a lightning strike as a potential source of ignition is 
not a significant possibility, due to the other conditions that would 
have to be present along with the lightning strike. Therefore, we find 
no change to the final rule is necessary in this regard.

Request To Increase Minimum Clearance

    One commenter asks us to increase the minimum clearance between the 
compensator for the Simmonds FQIS and fuel tank structure from 0.10 
inch, as specified in the referenced service bulletins, to 0.25 inch. 
The commenter states that clearance of 0.25 inch would account for the 
``sloshing'' of fuel in the tank. The commenter notes that its findings 
indicate that, should the compensator be moved 0.25 inch due to such 
``sloshing,'' and if the flapper check valve is fully extended, contact 
between these two components could occur. The commenter also notes that 
it has inspected three airplanes in its fleet for such contact between 
the compensator and flapper check valve and has found no evidence of 
such contact.
    We do not concur to increase the minimum clearance. We find that 
0.10 inch of clearance, as specified in the referenced service 
bulletins, is adequate to avoid contact between the compensator and 
flapper check valve, even accounting for the ``sloshing'' of fuel in 
the fuel tank. We note that any ``sloshing'' of fuel that would push 
the compensator in the direction of the flapper check valve would drive 
the flapper check valve to the closed position. No change to the final 
rule is necessary in this regard.

Request To Require Inspection for Damage of Compensator and Valve

    One commenter asks us to add a requirement to the proposed AD to 
inspect the compensator and flapper check valve for damage. The 
commenter advises that the added requirements should include damage 
limits and provide a technical source for accomplishment of any 
necessary corrective action.
    We do not concur. The commenter provides no technical data to 
support its request. We find that accomplishment of the actions 
required by this AD will prevent contact between the compensator and 
the flapper check valve and remove the potential arcing path inside the 
left and right main fuel tanks. We note that normal maintenance 
practices include removing the compensator and flapper check valve and 
replacing them with new parts if any damage is found. No change to the 
final rule is necessary in this regard.

Request To Increase Cost Impact

    One commenter asks us to increase the estimated cost impact stated 
in the proposed AD. Whereas, in the proposed AD, the FAA estimates that 
the proposed actions will take 5 work hours, the commenter indicates 
that the proposed actions will take 12 work hours. The commenter notes 
that a second person is required for safety reasons any time work is 
accomplished in the fuel tank.
    We do not concur to increase the estimated cost impact. The 
estimate that 5 work hours will be needed to complete the required 
actions is based on the best data available to date, as provided to the 
FAA by the airplane manufacturer. We note that this cost estimate is 
consistent with the manpower estimate in the referenced service 
bulletin, which states that 1.25 work hours per person (4 persons 
total) is necessary to do the bracket installation. 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 previously 
described. The FAA has determined that these changes will

[[Page 34822]]

neither increase the economic burden on any operator nor increase the 
scope of the AD.

Cost Impact

    There are approximately 938 Model 757 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 607 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 5 work hours per airplane to accomplish the required 
installation (not including time for gaining access and closing up), 
and that the average labor rate is $60 per work hour. Required parts 
will cost approximately $404 per airplane. Based on these figures, the 
cost impact of this AD on U.S. operators is estimated to be $427,328, 
or $704 per airplane.
    The cost impact figure discussed above is 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, Incorporation by 
reference, 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 adding the following new 
airworthiness directive:

2002-10-02  Boeing: Amendment 39-12748. Docket 2000-NM-414-AD.

    Applicability: Model 757 series airplanes listed in Boeing 
Service Bulletin 757-28-0057 or 757-28-0059, both Revision 1, both 
dated February 28, 2002, 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 (b) 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 compensator for the Simmonds fuel 
quantity indication system (FQIS) and a flapper check valve on a 
baffle rib in the main fuel tanks, which--in conjunction with 
another wiring failure outside the fuel tank--could result in an 
electrical arc and a consequent potential source of ignition in the 
fuel tank, accomplish the following:

Installation of Brackets

    (a) Within 48 months after the effective date of this AD, 
install an extender bracket for the compensator of the Simmonds FQIS 
in the left and right main fuel tanks (including ensuring minimum 
clearance between the compensators, wiring, and components, and the 
fuel tank structure, and testing the electrical bond in the fuel 
tank), according to the Accomplishment Instructions of Boeing 
Service Bulletin 757-28-0057 or 757-28-0059, both Revision 1, both 
dated February 28, 2002, as applicable.

    Note 2: Installations of extender brackets accomplished before 
the effective date of this AD according to Boeing Special Attention 
Service Bulletin 757-28-0057 or 757-28-0059, both dated September 
14, 2000, as applicable, are acceptable for compliance with 
paragraph (a) of this AD.

Alternative Methods of Compliance

    (b) 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. 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 3: 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

    (c) 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.

Incorporation by Reference

    (d) The actions shall be done in accordance with Boeing Service 
Bulletin 757-28-0057, Revision 1, dated February 28, 2002; or Boeing 
Service Bulletin 757-28-0059, Revision 1, dated February 28, 2002; 
as applicable. This incorporation by reference was approved by the 
Director of the Federal Register in accordance with 5 U.S.C. 552(a) 
and 1 CFR part 51. Copies may be obtained from Boeing Commercial 
Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

Effective Date

    (e) This amendment becomes effective on June 20, 2002.


    Issued in Renton, Washington, on May 8, 2002.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-12065 Filed 5-15-02; 8:45 am]
BILLING CODE 4910-13-U