AD 2001-14-19

[Federal Register Volume 66, Number 142 (Tuesday, July 24, 2001)]
[Rules and Regulations]
[Pages 38350-38354]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-18016]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-309-AD; Amendment 39-12330; AD 2001-14-19]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 767 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 767 series airplanes. For certain 
airplanes this AD requires rework of the bonding jumper assemblies on 
the drain tube assemblies of the slat track housing of the wings. For 
certain other airplanes, this AD requires repetitive inspections of the 
drain tube assemblies of the slat track housing of the wings to find 
discrepancies, and corrective actions, if necessary. This AD also 
provides for terminating action for the repetitive inspections. These 
actions are necessary to find and fix discrepancies of the bonding 
jumper assemblies, which could result in an in-tank ignition source due 
to electrostatic discharge or lightning. The actions also are necessary 
to find and fix discrepancies of the slat track drain tubes, which 
could result in fuel migrating into the tubes and leaking onto an 
engine or exhaust nozzle, and consequent risk of a fire when the 
airplane is stationary or during low speed taxiing. This action is 
intended to address the identified unsafe conditions.

DATES: Effective August 28, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 28, 2001.

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: Dennis Kammers, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 227-2956; 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 767 series 
airplanes was published in the Federal Register on December 22, 2000 
(65 FR 80796). For certain airplanes that action proposed to require 
rework of the bonding jumper assemblies. For certain other airplanes, 
that action proposed to require repetitive inspections of the drain 
tube assemblies of the slat track housing of

[[Page 38351]]

the wings to find discrepancies, and corrective actions, if necessary. 
That action also provides for terminating action for the repetitive 
inspections.

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.

Extend Compliance Time

    Several commenters ask that the compliance time for doing the 
terminating action specified in paragraph (b) of the proposed rule be 
extended, as follows.
    The first commenter states that the terminating action specified in 
paragraph (b) of the proposed rule requires compliance within 6,000 
flight hours or 18 months after the effective date of the AD, whichever 
occurs first; but current Boeing delivery schedules forecast a 12-month 
delivery time for the required kits. The commenter further states that 
they have ordered the material (kits), but the kits have not yet 
arrived, which affects the commenter's ability to comply with the 
proposed rule. The commenter proposes to do the terminating action at a 
heavy maintenance visit as soon as the kits are delivered, but asks 
that the compliance time be changed to within 48 months after the 
effective date of the AD to allow time for delivery of the kits. The 
commenter adds that the repetitive visual inspections for the fuel leak 
specified in the service bulletin and a compliance time of 48 months 
provide an acceptable level of safety.
    The second commenter states that the proposed rule, as written, 
does not take into consideration the amount of time needed to defuel 
and purge the fuel tanks. The commenter estimates that approximately 48 
hours are needed to ensure adequate safety before maintenance personnel 
may enter the fuel tanks. The commenter does not specify a change to 
the compliance time, but states that the time given to do the 
terminating action should be extended to allow for proper airplane 
scheduling.
    The third commenter states that the compliance time for doing the 
terminating action as specified in paragraph (b) of the proposed rule 
corresponds to a maintenance planning document ``C'' check interval, 
and is unreasonable. The commenter notes that the cracking of the slat 
track housing drain tubes is due to airframe vibration, which is 
related to flight hours, not calendar time. The commenter adds that the 
terminating action was considered optional based on ongoing inspections 
specified in the referenced service bulletin. The requirement to rework 
the drain tubes within 18 months after the effective date of the AD 
will not allow adequate time for airlines to obtain the necessary parts 
and do the rework within existing planned maintenance intervals, and 
does not allow for escalated maintenance programs. The commenter notes 
that the rework cannot be adequately done within planned maintenance 
outside of a ``C'' required to drain and vent the fuel tanks prior to 
tank entry. Additionally, there will be considerable impact on the 
airline operation when airplanes are scheduled for rework outside of 
routine maintenance checks. The commenter proposes that the calendar 
time limit for the terminating action specified in paragraph (b) of the 
proposed rule be extended to 24 months (the equivalent of a scheduled 
``C'' check). The commenter wants the flight hour threshold specified 
in paragraph (b) to remain the same, which means the actual operating 
period for the airplane prior to rework is unchanged.
    The fourth commenter states that they use Maintenance Planning 
Document MPD 57-50-00-A to inspect their airplanes at the enroute check 
before every flight. The commenter notes that this inspection is 
adequate to find fuel leaks, and no leaks have been found during these 
inspections. The commenter plans to do the terminating action specified 
in the proposed rule at the next heavy maintenance check per the normal 
defueling requirements of the MPD. The MPD task to defuel is at the 4C 
check, 72-month interval. The commenter adds that a 72-month compliance 
time could minimize their cost impact.
    The fifth commenter states that since the terminating action in the 
proposed rule was optional in the service bulletin referenced in 
paragraph (b) of the proposed rule, kits were ordered only on demand as 
the operators planned their maintenance action. Since the proposed rule 
mandates that the terminating action be done within 18 months, there is 
a shortage of parts. The manufacturer has delivered 176 kits to date, 
and currently there are only 2 kits in supply, with 200 kits on order 
that are due to arrive in July 2001. The commenter adds that they will 
not be able to get enough kits for all 671 airplanes within the 18-
month compliance time. The commenter also states that the repeat 
inspection at intervals not to exceed 500 flight hours, as specified in 
paragraph (a) of the proposed rule, maintains an adequate level of 
safety until the terminating action can be done. The commenter notes 
that there have not been any reported leaks at the slat track drain 
tube location since the proposed rule was issued. The commenter asks 
that the compliance time specified in paragraph (b) of the proposed 
rule be changed to within 6,000 flight hours or 36 months after the 
effective date of the AD, whichever comes first, to allow operators 
time to obtain the necessary parts.
    The FAA concurs with the commenters that the compliance time 
required by paragraph (b) of the final rule should be extended somewhat 
to ensure that enough parts are available to do the required actions 
within the specified compliance time. In developing an appropriate 
compliance time for the terminating action required by the final rule, 
we considered not only the degree of urgency associated with addressing 
the unsafe condition, but the practical aspect of incorporating the 
required drain tube modification on the Model 767 fleet in a timely 
manner. Other factors included in the determination of an acceptable 
compliance time are that we informed the Air Transport Association in 
March 1998 of our plans to mandate appropriate service information to 
alleviate the unsafe condition, and affected operators have had access 
to the service bulletin that was revised to add the terminating 
modification since December 1998. Therefore, operators have had time to 
incorporate into their individual maintenance plans the inspections and 
terminating action required by this final rule.
    It is our intent in this final rule to have the terminating action 
done within the time frame of a `C' check maintenance interval. We took 
the commenters' recommendations into account, as well as the time 
necessary to do the terminating action, and we find that a 24-month 
compliance time should correspond with the regular maintenance 
schedules of the majority of affected operators. An extension of the 
compliance time to 24 months will not adversely affect safety because 
the inspections required by paragraph (a) of the final rule will 
provide an acceptable level of safety until the terminating action 
required by paragraph (b) is done. Paragraph (b) of the final rule has 
been changed accordingly.
    In response to the commenters' concerns that parts will not be 
available for installation within the compliance time required by the 
final rule, we have confirmed with the manufacturer that parts will be 
available to support a compliance time of 24 months after the effective 
date of this final rule.

[[Page 38352]]

    In response to the third commenter's statement that the cracking of 
the slat track housing drain tubes is due to airframe vibration, which 
is related to flight hours, not calendar time; our determination is 
that the drain tubes failed in service due to corrosion.

Separate Rulemaking Actions

    One commenter asks that Boeing Service Bulletins 767-57A0060, 
Revision 1, and 767-57-0068, referenced in the proposed rule as the 
appropriate sources of service information for accomplishment of the 
actions, be addressed in two separate rulemaking actions. The commenter 
states that these two service bulletins do not address the same 
discrepant condition and should not be grouped together in one proposed 
rule.
    The FAA does not concur. We agree that two unsafe conditions do 
exist with the same drain tube installation, but we consider it 
acceptable to address both conditions in one rule. The reasons for this 
are as follows:
    Boeing Service Bulletin 767-57A0060, Revision 1, provides 
procedures for repetitive visual inspections of the drain tube 
assemblies of the slat track housing of the wings to find 
discrepancies. Such discrepancies may lead to an airplane fire as a 
result of fuel leakage onto an engine or exhaust nozzle. The service 
bulletin also provides procedures for replacement of the existing drain 
tube assembly with a newly designed assembly that would constitute 
terminating action for the repetitive inspections.
    Boeing Service Bulletin 767-57-0068 provides procedures for 
modification of the bonding jumper assembly on the drain tube assembly 
of the slat track housing of the wings. An earlier production 
installation of the bonding assembly on the newly designed drain tube 
assembly did not meet the current bonding specifications. Those 
airplanes with the earlier production installation must have the 
bonding provisions modified to protect against an in-tank ignition 
source due to electrostatic discharge or lightning. Incorporation of 
this service bulletin will bring affected airplanes into the same 
configuration as those airplanes modified by Service Bulletin 767-
57A0060. Clarification of the related procedures in these two service 
bulletins was provided in the preamble of the proposed rule.

Revise Preamble Language

    One commenter states that the Summary and Discussion sections of 
the proposed rule should be changed to explicitly state that only the 
numbers 5 and 8 inboard slat track housing drain locations are affected 
by the proposed rule. The commenter adds that it also should be 
explicitly stated that visual inspections are to be done at the 
exterior lower wing surface drain locations, as shown in Figure 2 of 
Boeing Service Bulletin 767-57A0060, Revision 1, located on page 21.
    The FAA concurs with these comments and acknowledges that the 
description of the area (numbers 5 and 8 inboard) of the drain assembly 
of the slat track housing affected could have been more specific in the 
Summary and Discussion sections, but the Discussion section is not 
restated in this final rule. The intent of the Summary section of the 
final rule is to provide a brief explanation of the unsafe condition 
and the actions necessary to find and fix any discrepancies. We have 
revised the Summary section, as well as the other applicable sections 
in this final rule, to further clarify the unsafe condition and the 
specified actions.
    One commenter asks that the Differences section of the proposed 
rule be changed. The commenter points out that there is a typographical 
error in the MPD section number that is specified in the Differences, 
the correct number is Section 57-50-00-A.
    We concur that a typographical error in the Differences section 
resulted in an incorrect reference to Section 57-59-00-A of the MPD, 
instead of the correct reference to Section 57-50-00-A. But this final 
rule does not restate the Differences section of the proposed rule 
wherein the commenter has requested changes. That difference merely 
stated that the proposed rule would require accomplishment of the 
initial and repeat visual inspections regardless of earlier 
accomplishment of the inspection specified in the MPD.

Maintenance Planning Document (MPD)

    One commenter states that Boeing Service Bulletin 767-57A0060, 
Revision 1, describes the Boeing 767 MPD, Section 57-50-00-A, as an 
acceptable means to inspect and detect damage and/or fuel leakage, as 
an alternative to the visual inspection specified in Part I of the 
service bulletin. The commenter asks that the FAA confirm that the MPD 
can be used instead of doing the visual inspection specified in 
paragraph (a) of the proposed rule.
    The FAA does not concur. As stated in the Differences section of 
the proposed rule, discussed previously, the final rule requires 
accomplishment of the initial and repeat visual inspections regardless 
of earlier accomplishment of the inspection specified in the MPD. This 
is necessary because the inspection in the MPD does not require a 
minimum amount of fuel in each wing tank, but the visual inspections 
described in Part I of the service bulletin specify a minimum of 4,400 
gallons of fuel in each wing tank to ensure adequate fuel coverage over 
the drain tubes during the fuel leakage check.

Cost Impact

    One commenter states that the number of work hours estimated for 
doing the actions in the proposed rule, as specified in the service 
bulletins, are more accurate than the number of work hours specified in 
the cost impact section of the proposed rule. The commenter notes that 
the estimate for replacement of the drain tube assemblies as specified 
in the proposal is 12 work hours, but the estimate specified in the 
applicable service bulletin is 40 work hours for the replacement. The 
estimate for rework of the bonding jumper assemblies specified in the 
proposal is 4 work hours, but the estimate specified in the applicable 
service bulletin is 25 work hours. The commenter asks that the work 
hours estimated in the service bulletins be used in the Cost Impact 
section of the proposed rule.
    The FAA does not concur. The cost impact information (below) 
estimates only the ``direct'' costs of the specific actions required by 
this final rule. The number of work hours necessary to do the required 
actions was provided to us by the manufacturer, based on the data 
available to date. We recognize that in doing the actions required by 
this final rule, operators may incur ``incidental'' costs in addition 
to the ``direct'' costs. The cost analysis in AD rulemaking actions, 
however, typically does not include incidental costs, such as the time 
required to gain access and close-up; planning time; or time 
necessitated by other administrative actions. Because incidental costs 
may vary significantly from operator to operator, they are almost 
impossible to calculate. Further, because ADs require specific actions 
to address specific unsafe conditions, they appear to impose costs that 
would not otherwise be incurred by operators. However, because of the 
general obligation of operators to maintain and operate airplanes in an 
airworthy condition, this cost estimate is inaccurate. Attributing 
those costs to the requirements of this final rule is unrealistic 
because in the interest of maintaining and operating safe airplanes, 
operators would do the required actions even if they were not required 
to do the final rule.

[[Page 38353]]

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

Cost Impact

    There are approximately 745 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 275 airplanes of U.S. registry 
will be affected by this AD.
    For airplanes listed in Boeing Service Bulletin 767-57A0060, 
Revision 1 (228 U.S.-registered airplanes): It will take approximately 
1 work hour per airplane to accomplish the required inspection, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the required inspection on U.S. operators is estimated 
to be $13,680, or $60 per airplane, per inspection cycle.
    It will take approximately 12 work hours per airplane to accomplish 
the required replacement of the drain tube assemblies specified in 
Boeing Service Bulletin 767-57A0060, Revision 1, at an average labor 
rate of $60 per work hour. Required parts will cost approximately 
$5,236 per airplane. Based on these figures, the cost impact of the 
required replacement on U.S. operators is estimated to be $1,357,968, 
or $5,956 per airplane.
    For airplanes listed in Boeing Service Bulletin 767-57-0068, (47 
U.S.-registered airplanes): It will take approximately 4 work hours per 
airplane to accomplish the required rework of the bonding jumper 
assemblies, at an average labor rate of $60 per work hour. Required 
parts will cost approximately $322 per airplane. Based on these 
figures, the cost impact of the required rework on U.S. operators is 
estimated to be $26,414, or $562 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, 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:

2001-14-19  Boeing: Amendment 39-12330. Docket 2000-NM-309-AD.

    Applicability: Model 767 series airplanes, line numbers 1 
through 757 inclusive, 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) 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 find and fix discrepancies (bonding, loose fittings, 
cracking) of the bonding jumper assemblies, which could result in an 
in-tank ignition source due to electrostatic discharge or lightning; 
and of the slat track drain tubes, which could result in fuel 
migrating into the tubes and leaking onto an engine or exhaust 
nozzle, and consequent risk of a fire when the airplane is 
stationary or during low speed taxiing; accomplish the following:

Repetitive Inspections/Corrective Action

    (a) For airplanes listed in Boeing Service Bulletin 767-57A0060, 
Revision 1, dated December 31, 1998; within 500 flight hours after 
the effective date of this AD: Do a general visual inspection of the 
drain tube assemblies of the slat track housings of the wings to 
find discrepancies (loose fittings, cracked tubes, fuel leaks), per 
Part I of the Accomplishment Instructions of the service bulletin.
    (1) If any discrepancies are found, before further flight, 
rework the drain tube assembly per Part II of the Accomplishment 
Instructions of the service bulletin; repeat the inspection at 
intervals not to exceed 500 flight hours until accomplishment of the 
requirements in paragraph (b) of this AD.
    (2) If no discrepancies are found, repeat the inspection 
thereafter at intervals not to exceed 500 flight hours, until 
accomplishment of the requirements in paragraph (b) of this AD.

    Note 2: For the purposes of this AD, a general visual inspection 
is defined as: ``A visual examination of an interior or exterior 
area, installation, or assembly to find obvious damage, failure, or 
irregularity. This level of inspection is made under normally 
available lighting conditions such as daylight, hangar lighting, 
flashlight, or drop-light and may require removal or opening of 
access panels or doors. Stands, ladders, or platforms may be 
required to gain proximity to the area being checked.''

Terminating Action for Repetitive Inspections

    (b) For airplanes specified in paragraph (a) of this AD, within 
6,000 flight hours or 24 months after the effective date of this AD, 
whichever occurs first: Replace the drain tube assemblies of the 
slat track housings of the wings (including general visual 
inspection and repair) per Part III of the Accomplishment 
Instructions of Boeing Service Bulletin 767-57A0060, Revision 1, 
dated December 31, 1998. Any applicable repair must be accomplished 
prior to further flight. Accomplishment of this paragraph terminates 
the repetitive inspections required by paragraph (a) of this AD.

[[Page 38354]]

Rework of Bonding Jumper Assemblies

    (c) For airplanes listed in Boeing Service Bulletin 767-57-0068, 
dated September 16, 1999; within 5,000 flight cycles or 22 months 
after the effective date of this AD, whichever occurs first: Rework 
the bonding jumper assembly of the drain tube assemblies of the slat 
track housing of the wings (including general visual inspection and 
repair) per the Accomplishment Instructions of the service bulletin. 
Any applicable repair must be accomplished prior to further flight. 
Accomplishment of this paragraph terminates the requirements of this 
AD.

Alternative Methods of Compliance

    (d) 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 send 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 Permit

    (e) Special flight permits may be issued per 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

    (f) The actions shall be done in accordance with Boeing Service 
Bulletin 767-57A0060, Revision 1, dated December 31, 1998, and 
Boeing Service Bulletin 767-57-0068, dated September 16, 1999; 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

    (g) This amendment becomes effective on August 28, 2001.

    Issued in Renton, Washington, on July 12, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 01-18016 Filed 7-23-01; 8:45 am]
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