[Federal Register Volume 85, Number 194 (Tuesday, October 6, 2020)]
[Rules and Regulations]
[Pages 62993-63002]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-21997]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6141; Product Identifier 2015-NM-048-AD; Amendment 
39-21237; AD 2020-18-16]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain The Boeing Company Model 767-200, -300, -300F, and -400ER 
series airplanes. This AD was prompted by the FAA's analysis of the 
Model 767 fuel system reviews conducted by the manufacturer. This AD 
requires modifying the fuel quantity indicating system (FQIS) to 
prevent development of an ignition source inside the center fuel tank 
due to electrical fault conditions. This AD also provides optional 
actions for cargo airplanes. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective November 10, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of November 10, 
2020.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110 SK57, Seal Beach, CA 
90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. You may view this service information at the 
FAA, Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability of 
this material at the FAA, call 206-231-3195. It is also available on 
the internet at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2016-6141.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2016-
6141; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this final rule, any comments received, and other information. The 
address for Docket Operations is U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Jon Regimbal, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3557; email: 
Jon.Regimbal@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain The Boeing 
Company Model 767-200, -300, -300F, and -400ER series airplanes. The 
NPRM published in the Federal Register on May 4, 2016 (81 FR 26747). 
The NPRM was prompted by the FAA's analysis of the Model 767 fuel 
system reviews conducted by the manufacturer. The NPRM proposed to 
require modifying the FQIS to prevent development of an ignition source 
inside the center fuel tank due to electrical fault conditions. The 
NPRM also proposed to provide optional actions for cargo airplanes. The 
FAA is issuing this AD to address ignition sources inside the center 
fuel tank, which, in combination with flammable fuel vapors, could 
result in a fuel tank explosion and consequent loss of the airplane.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Support for the NPRM

    The Air Line Pilots Association, International (ALPA) and National 
Air Traffic Controllers Association (NATCA) supported the intent of the 
NPRM. Additional comments from NATCA are addressed below.

Request To Withdraw NPRM: No Unsafe Condition

    Boeing requested that the FAA withdraw the NPRM. Boeing suggested 
that, by requiring center fuel tank FQIS wire separation for passenger 
airplanes that have not incorporated a nitrogen generating system 
(NGS), the NPRM specifically addresses airplanes regulated by the 
European Union Aviation Safety Agency (EASA) and other civil aviation 
authorities and the lack of a flammability reduction means (FRM) rule. 
Boeing stated that because it considered the use of FRM (NGS) to 
address unknown ignition sources as the final corrective action, Boeing 
has not developed center tank FQIS wire separation service instructions 
for passenger aircraft. Boeing stated that it believes no unsafe 
condition exists and does not feel that the lack of FRM rule 
harmonization should cause additional work and expense for airlines.
    The FAA disagrees with the commenter's request. The FAA determined 
that an unsafe condition exists using the criteria in FAA Policy 
Memorandum ANM100-2003-112-15, ``SFAR 88--Mandatory Action Decision 
Criteria,'' dated February 25, 2003.\1\ That policy was used to 
evaluate the noncompliant design areas identified in the manufacturer's 
fuel system reviews and to determine which noncompliance issues were 
unsafe conditions that required corrective action under 14 CFR

[[Page 62994]]

part 39. The FAA's unsafe condition determination was not based on an 
assessment of average risk or total fleet risk, but rather was driven 
by the qualitative identification of an unacceptable level of 
individual risk that exists on flights that are anticipated to occur 
with a preexisting latent in-tank failure condition and with a 
flammable center fuel tank. For these reasons, and based on further 
detailed responses to similar comments in the supplemental NPRM (SNPRM) 
for Docket No. FAA-2012-0187 (80 FR 9400, February 23, 2015), and in 
the subsequently issued final rule, AD 2016-07-07, Amendment 39-18452 
(81 FR 19472, April 5, 2016) (``AD 2016-07-07''), which addressed the 
same unsafe condition for Boeing Model 757 airplanes, the FAA has 
determined that it is necessary to issue this final rule.
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Request To Withdraw NPRM: Unjustified by Risk

    Airlines for America and the Cargo Airline Association, in 
consolidated comments (A4A/CAA), United Parcel Service (UPS) and FedEx 
requested that the FAA withdraw the NPRM. A4A/CAA and UPS cited 
comments submitted by Boeing to Docket No. FAA-2012-0187 in which 
Boeing stated that the risk is ``less than extremely improbable.'' A4A/
CAA added that Boeing does not believe that an unsafe condition exists. 
UPS stated that Boeing's comments demonstrate an unsafe condition does 
not exist. A4A/CAA and UPS noted that they consider the Boeing comments 
to be applicable to the airplane models in the NPRM. FedEx stated that 
the proposed rule is not supported with a safety risk assessment and it 
is therefore difficult to understand the validity and justification of 
the proposed rule.
    UPS stated that an agency is required to consider all relevant 
factors and articulate a satisfactory explanation for its action. UPS 
noted that the FAA is apparently basing its decision to issue the AD on 
historical Special Federal Aviation Regulation (SFAR) No. 88 design 
reviews that have been superseded by the more recent Boeing analysis 
and favorable operational experience in the years since the SFAR 88 
reviews were completed.
    The FAA disagrees with the commenters' requests. The FAA notes that 
Boeing's comments were addressed in the SNPRM for Docket No. FAA-2012-
0187 in the comment response for ``Request To Withdraw NPRM (77 FR 
12506, March 1, 2012): Unjustified by Risk.'' As explained in that 
comment response, in addition to examining average risk and total fleet 
risk, the FAA examines the individual flight risk on the worst 
reasonably anticipated flights. In general, the FAA issues ADs in cases 
where reasonably anticipated flights with preexisting failures (either 
due to latent failure conditions or allowable dispatch configurations) 
are vulnerable to a catastrophic event due to an additional foreseeable 
single failure condition. This is because the FAA considers operation 
of flights vulnerable to a potentially catastrophic single failure 
condition to be an excessive safety risk to the passengers on those 
flights. The FAA has determined that the currently mandated SFAR 88 
service bulletins, airworthiness limitations, and critical design 
configuration control limitations do not adequately address the unsafe 
condition identified in this AD and therefore it is necessary to issue 
this final rule. The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: No Safety Risk Assessment

    FedEx requested that the FAA withdraw the NPRM, stating that a 
safety risk assessment was not included with the proposed rule. FedEx 
quoted the NPRM to the fuel tank flammability reduction (FTFR) rule (70 
FR 70922, November 23, 2005), which noted that the FAA had not 
evaluated the risk to all-cargo airplanes because they are derivatives 
of passenger airplanes. FedEx noted that the NPRM to the FTFR rule also 
stated that the risk may be lower for all-cargo operations due to fewer 
miles flown and more nighttime operations when temperatures are lower. 
FedEx stated that its fleet utilization is only about 5 flight hours 
per day, which would further lower the risk of accidents. FedEx 
requested that the FAA provide a safety risk assessment for the Model 
767 FQIS that justifies the proposed rule.
    The FAA does not agree to withdraw the NPRM. The FAA's 
determination that an unsafe condition exists was not based on a 
calculation of the total risk of an accident occurring in the life of 
the fleet. Instead, the FAA's determination was based on an analysis 
showing that numerous Model 767 all-cargo airplane flights will occur 
with a latent FQIS in-tank failure, and that such flights will not 
provide the minimum acceptable level of safety for transport airplanes 
defined in FAA regulations and policy because they will not be fail-
safe for one additional electrical wiring fault. This was discussed in 
detail in the SNPRM for Docket No. FAA-2012-0187, which addresses the 
same issue for Model 757 airplanes, in the comment response for 
``Request To Withdraw NPRM (77 FR 12506, March 1, 2012): Unjustified by 
Risk.'' That comment response is applicable to this AD. The FAA has not 
changed this AD regarding this issue.

Request To Withdraw NPRM: Probability Analysis Inconsistent With 
Regulatory Requirements

    A4A/CAA and UPS requested that the FAA withdraw the NPRM. The 
commenters stated that the assumption of a single failure regardless of 
probability is inconsistent with 14 CFR part 25 regulatory 
requirements. The commenters referred to the phrase ``regardless of 
probability'' associated with single failures. A4A/CAA and UPS 
acknowledged that the term is used with single failures in FAA Advisory 
Circular (AC) 25.981-1C,\2\ ``Fuel Tank Ignition Source Prevention 
Guidelines,'' but since that term does not appear in 14 CFR 
25.981(a)(3), the commenters considered its use arbitrary, possibly 
introducing additional requirements not included in that section. A4A/
CAA and UPS stated that the ``worst reasonably anticipated flight'' is 
a flight with a latent FQIS failure and a high-flammability tank, and 
this ``latent plus one'' failure--regardless of probability of a single 
failure--is not consistent with 14 CFR 25.981(a)(3).
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    The FAA disagrees with the commenters' request. The FAA notes that 
the commenters' assertion about the intent of 14 CFR 25.981(a)(3) is 
incorrect based on both the language of the rule and on the published 
rulemaking documents. The absence of a probabilistic qualifier in both 
the ``from each single failure'' clause and in the ``from each single 
failure in combination with each latent failure not shown to be 
extremely remote'' clause in 14 CFR 25.981(a)(3) in fact means just 
that--there is no probabilistic qualifier intended by the regulation. 
The intent for single failures in these two scenarios to be considered 
regardless of probability of the single failure was explicitly stated 
in the NPRM for 14 CFR 25.981, as amended by amendment 25-102 (66 FR 
23085, May 7, 2001). That NPRM stated, in pertinent part, that it would 
also add a new paragraph (a)(3) to require that a safety analysis be 
performed to demonstrate that the presence of an ignition source in the 
fuel tank system could not result from ``any single failure, from any 
single failure in combination with any latent failure condition not 
shown to be extremely remote, or from any combination of failures not 
shown to be extremely improbable.'' These new

[[Page 62995]]

requirements would define three scenarios that must be addressed in 
order to show compliance with the proposed paragraph (a)(3). ``The 
first scenario is that any single failure, regardless of the 
probability of occurrence of the failure, must not cause an ignition 
source. The second scenario is that any single failure, regardless of 
the probability occurrence, in combination with any latent failure 
condition not shown to be at least extremely remote (i.e., not shown to 
be extremely remote or extremely improbable), must not cause an 
ignition source. The third scenario is that any combination of failures 
not shown to be extremely improbable must not cause an ignition 
source.''
    The preamble to the final rule for amendment 25-102 made a nearly 
identical statement, including the same uses of the phrase ``regardless 
of probability.'' The FAA has determined that it is necessary to 
proceed with issuance of this final rule as proposed. Further details 
and a description of the FAA's risk assessment can be found in 
responses to similar comments in a related SNPRM that addressed the 
same unsafe condition for Model 757 airplanes, in Docket No. FAA-2012-
0187, and in the subsequently issued final rule, AD 2016-07-07, 
amendment 39-18452 (81 FR 19472, April 5, 2016) (``AD 2016-07-07''). No 
change to this AD was made in response to these comments.

Request To Withdraw NPRM: No Technical Justification

    FedEx requested that the FAA withdraw the NPRM, stating that the 
proposed requirement has not been technically justified. FedEx stated 
that 14 CFR 25.981, as amended by amendment 25-102; and SFAR 88 (in 14 
CFR part 21); required the aircraft original equipment manufacturer 
(OEM) to evaluate the Model 767 fuel system and components for 
compliance with the new requirements. FedEx added that it understands 
that Boeing and Goodrich Aerospace determined that the only FQIS 
component that did not meet those requirements was the center tank's 
densitometer. FedEx noted that AD 2010-06-10, Amendment 39-16234 (75 FR 
15322, March 29, 2010) (``AD 2010-06-10''), was issued to install 
support hardware, modify the wiring of the center wing tank FQIS 
densitometer, and replace the hot short protector for the center tank. 
FedEx added that Boeing and Goodrich did not determine a need for 
additional barrier devices on the Model 767 FQIS.
    The FAA does not agree to withdraw the rule. The FAA notes that 
FedEx's understanding of the results of Boeing's Model 767 FQIS SFAR 88 
analysis is not correct. Boeing's analysis also identified the FQIS 
latent-plus-one condition as non-compliant with 14 CFR 25.981(a)(3). 
Consequently, the FAA has determined modifying the FQIS is necessary to 
prevent development of an ignition source inside the center fuel tank 
due to electrical fault conditions. The FAA has not changed this AD 
regarding this issue.

Request To Withdraw NPRM: No New Data Since FTFR Rulemaking

    A4A/CAA and UPS requested that the FAA withdraw the NPRM based on a 
lack of new data since the issuance of the FTFR rule (73 FR 42444, July 
21, 2008). The commenters referred to the FTFR rule and decision to not 
require FRM for all-cargo airplanes, and the FAA's intent to gather 
additional data and consideration of further rulemaking if flammability 
of these airplanes is excessive. UPS stated that since the FTFR rule, 
no additional data has been publicly introduced that would support or 
justify the applicability of this rulemaking to all-cargo aircraft. The 
commenters also referred to the FAA's response to comments in the 
preamble to the SNPRM for Docket No. FAA-2012 0187, which documented 
the FAA's decision on applicability of FRM and cost estimates. The 
commenters stated that the FAA response was misleading and not factual 
since manufacturers did not begin detailed designs to address the 
proposed unsafe condition until after the FTFR rule was published. The 
commenters added that the FAA did not discuss other changes to the FQIS 
system in the FTFR rule.
    The FAA disagrees with the commenters' request. The FAA notes that 
the FTFR rule and FQIS ADs are two different issues with separate FAA 
actions. The intent of the FTFR rule was to provide an order of 
magnitude reduction in the rate of fuel tank explosions for the 
airplanes affected by that rule through adding a new airworthiness 
standard for the flammability of fuel tanks. The FAA notes that the 
FTFR rule was never intended to be a replacement for the issuance of 
ADs to address identified unsafe conditions. An unsafe condition due to 
the identified FQIS latent-plus-single failure issue in high-
flammability fuel tanks was determined to exist during the SFAR 88 AD 
Board held by the FAA in 2003 using the guidance in FAA Policy 
Memorandum ANM100-2003-112-15 for high-flammability fuel tanks, 
including the center fuel tank on Model 767-200, -300, -300F, and -
400ER series airplanes. That same issue was not considered to be an 
unsafe condition in low-flammability wing fuel tanks based on that same 
policy memorandum. The FAA has not changed this AD regarding this 
issue.

Request To Withdraw NPRM: Insufficient Justification for AD

    Based on an assertion that the FAA did not sufficiently explain how 
the unsafe condition justifies AD rulemaking, UPS requested that the 
FAA withdraw the NPRM. UPS stated that the FTFR rule did not suggest 
that any future modifications of FQIS systems had been considered. UPS 
contended that all-cargo operators were surprised and prejudiced by 
costly proposed FQIS modifications that are unsupported by both an 
updated risk assessment and full cost/benefit analysis that consider 
the pertinent facts. UPS alleged that the FAA did not fully explain or 
justify its decision making for the NPRM, and concluded that the NPRM 
is arbitrary and does not reflect properly reasoned agency action.
    The FAA disagrees with the commenter's request. A review of the 
rulemaking record shows that the commenter's first assertion is not 
correct. The FAA notes that Section III.K.5. of the preamble of the 
FTFR rule states that ``the findings from the analysis required by SFAR 
88 showed that most transport category airplanes with high-flammability 
fuel tanks needed transient suppression units (TSUs) to prevent 
electrical energy from airplane wiring from entering the fuel tanks in 
the event of a latent failure in combination with a single failure.'' 
In addition, the NPRM for the FTFR rule states: ``As part of the safety 
reviews of SFAR 88, we have identified other models that likewise would 
need a transient suppression device.'' These statements indicate that 
the FAA expects to take AD action on multiple airplane models to 
address FQIS issues identified through the SFAR 88 analyses. The 
preamble of the FTFR rule also states that the proposed FRM has the 
potential to reduce the industry cost associated with those expected 
ADs because the installation of an FRM likely would eliminate the need 
to further address the FQIS issue through AD actions.
    The purpose of those statements was to note that there would be 
some cost savings to industry resulting from the elimination of other 
actions required to address an unsafe condition for the airplanes 
affected by the proposed rules, and to point out that the FAA did not 
take credit for those potential cost reductions in assessing the cost 
of the FTFR rule because the costs were not

[[Page 62996]]

well understood at the time. That statement was not a commitment by the 
FAA to forego issuing ADs if necessary to address an identified unsafe 
condition on the airplanes but rather to not require the affected 
airplanes to incorporate FRM. As noted previously, the NPRM for the 
FTFR rule and the FTFR rule both made statements indicating that the 
FAA expects to issue AD actions on multiple airplane models to address 
FQIS issues identified through the SFAR 88 analyses. The FAA explained 
the unsafe condition and the risk on anticipated flights with a pre-
existing latent failure condition in the NPRM to this final rule. The 
FAA also provided an estimate of the costs associated with the proposed 
AD in accordance with FAA rulemaking policy and the Administrative 
Procedures Act. The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: NPRM Arbitrary and Inconsistently Applied

    A4A/CAA and UPS requested that the FAA withdraw the NPRM. The 
commenters noted that airplanes with FRM are not included in the 
applicability, and the NPRM would therefore not fully address the 
unsafe condition. The commenters added that the distinction between 
high- and low-flammability exposure time fuel tanks as used in the NPRM 
is arbitrary. The commenters stated that an arbitrary differentiation 
of high- versus low-flammability as decisional criteria for the need 
for corrective action does not take into account the actual probability 
of the impact of the difference in flammability on the potential of 
catastrophic failure. The commenters also stated that allowing the 
proposed alternative actions for cargo airplanes does not fully address 
the unsafe condition in the NPRM. The commenters referenced the FAA's 
response to comments in AD 2016-07-07 regarding this issue. The 
commenters summarized numerical analysis showing no significant 
difference in risk between high- and low-flammability fuel tanks. The 
commenters concluded that the FAA's risk analysis is arbitrary and an 
unsafe condition does not exist.
    The FAA disagrees with the assertion that the NPRM is arbitrary and 
inconsistent. The NPRM follows defined policy in FAA Policy Memorandum 
ANM100-2003-112-15, and consistently applies the policy to several 
airplane models with similar unsafe conditions, similar to AD 2016-07-
07. The FAA defined the difference between low- and high-flammability 
exposure time fuel tanks based on recommendations from the Aviation 
Rulemaking Advisory Committee Fuel Tank Harmonization Working Group 
(FTHWG). The preamble to the final rule for amendment 25-102, which 
amended 14 CFR 25.981, defined this difference as based upon comparison 
of ``the safety record of center wing fuel tanks that, in certain 
airplanes, are heated by equipment located under the tank, and unheated 
fuel tanks located in the wing.'' The FTHWG concluded that the safety 
record of fuel tanks located in the wings was adequate and that if the 
same level could be achieved in center wing fuel tanks, the overall 
safety objective would be achieved.
    In the response to comments in the preamble to the final rule for 
AD 2016-07-07 referenced by the commenters, the FAA described why FRM 
or alternative actions for cargo airplanes provide an acceptable level 
of safety, even if they do not completely eliminate the non-compliance 
with 14 CFR 25.981(a)(3).
    The fuel tank explosion history for turbojet/turbofan powered 
transport airplanes fueled with kerosene type fuel, outside of 
maintenance activity, has consisted of explosions of tanks that (1) are 
not conventional aluminum wing tanks and (2) spend a considerable 
amount of their operating time empty. The service history of 
conventional aluminum wing tanks has been acceptable. The intent of the 
difference in decision criteria in FAA Policy Memorandum ANM100-2003-
112-15 was intended to give credit for this satisfactory service 
experience, and to differentiate between tanks with a level of 
flammability similar to that of a conventional wing tank and those with 
a significantly higher level of flammability.
    The numerical analysis provided by the commenters is inconsistent 
with the fuel tank explosion service history. There are at least three 
identifiable physics-based reasons for that inconsistency. First, low-
flammability tanks on most types of airplanes are main tanks that are 
the last tanks used. During a large portion of their operating time, 
the systems and structural features that have the potential to be 
ignition sources in the event of a failure condition are covered with 
liquid fuel, and an ignition source, if it occurs, is likely to be 
submerged. When a potential ignition source in a main tank is 
uncovered, it is likely to be later in the flight when the tank is cool 
and no longer flammable. The commenters' analysis does not account for 
this significant effect. Second, the numerical analysis used by the 
commenters assumes that any given ignition source has a random 
occurrence in time at the estimated probability, and that, in order for 
an explosion to occur, that random occurrence of an ignition source 
needs to coincide with the tank being in a flammable state. In fact, 
many of the identified ignition threats do not simply occur briefly and 
then go away. Instead, a fault occurs that, until it is discovered and 
corrected, repeatedly creates an ignition source, and repeatedly tests 
whether flammable conditions exist.
    Third, the flammability of low-flammability fuel tanks is typically 
dependent on weather, and a low-flammability fuel tank may operate for 
months without ever becoming flammable. This is not true of most high-
flammability fuel tanks, which typically have significant on-airplane 
heat sources driving their temperature. This factor can mean that, on 
some airplanes, an in-tank latent failure can occur and, after some 
period of time, be detected and corrected without the low flammability 
tank ever having flammable conditions. The numerical analysis provided 
by the commenters does not account for these significant factors. The 
difference in likelihood of a failure that results in repeated ignition 
source events causing a tank explosion is not simply proportional to 
difference in the fleet average flammability of the tank for the 
reasons stated above. The FAA has not changed this AD regarding this 
issue.

Request To Withdraw NPRM: Arbitrary and Inconsistent Wire Separation 
Standards

    A4A/CAA and UPS requested that the FAA withdraw the NPRM based on a 
lack of consistent design standards for FQIS wire separation. The 
commenters assumed that the approved standard for the retrofit is a 2-
inch wire separation minimum, which the commenters considered arbitrary 
and inconsistently applied. The commenters reported that the amount of 
wiring capable of meeting that separation standard varies widely among 
airplane models. A4A/CAA and UPS also acknowledged that other 
separation methods were used in areas not meeting the 2-inch wire 
separation requirement.
    The FAA does not agree with the commenters' request. The degree of 
physical isolation of FQIS wiring from other wiring, whether provided 
by physical distance or barrier methods, that is necessary to eliminate 
the potential for hot shorts due to wiring faults is dependent on the 
materials used, the wire securing methods, and the possible types of 
wiring faults. The FAA relied on the manufacturer to assess the details 
of the design and to propose the appropriate isolation

[[Page 62997]]

measures. While 2 inches of physical separation may appear to be an 
arbitrary number, it was the distance proposed by the manufacturer as 
appropriate for their design based on analysis of the design details. 
The FAA has not changed this AD regarding this issue.

Request To Withdraw NPRM: Not Justified Based on Cost-Benefit Analysis

    FedEx noted that the proposed AD does not include a cost-benefit 
analysis. FedEx added that in the NPRM for the FTFR rule, the FAA 
stated that proposal would not extend to airplanes used in all-cargo 
operations because the cost did not appear justified by the associated 
benefits. FedEx acknowledged that the FAA's statement was meant for the 
installation of the NGS. However, FedEx stated that it believes the 
current proposed rule would provide cost-benefit results that are less 
justifiable than the FTFR rule. FedEx stated that while the costs may 
be comparable, the benefits associated with the FQIS modification will 
be less. The FAA infers that FedEx is requesting that the proposed rule 
be withdrawn because it cannot be shown to be cost beneficial.
    The FAA does not agree that the proposed AD should be withdrawn or 
that a full cost-benefit analysis is required to justify AD action to 
address the identified unsafe condition. In the NPRM to this AD, the 
FAA provided the cost analysis that is required by FAA policy and the 
Administrative Procedures Act. In the NPRM, the FAA described the basis 
for the unsafe condition determination, noting that a significant 
number of flights are anticipated to occur in a non-fail-safe 
condition. Such flights would not meet the minimum level of safety 
expectations for transport airplanes. The cost of the requirement in 
the airworthiness standards to provide fail-safe design was justified 
at the time of rulemaking for the associated regulatory standards. The 
fact that a design is later discovered not to have met the regulatory 
standard and is very expensive to correct should not and does not 
prevent the FAA from requiring appropriate corrective action to restore 
a design to the minimum acceptable level of safety defined in the 
airworthiness standards for that product. The FAA has not changed this 
AD regarding this issue.

Request To Withdraw NPRM: Inadequate Fleet Exposure and Cost Estimates

    Boeing requested that the FAA withdraw the NPRM. Boeing stated that 
the fleet exposure for the affected fleet continues to decrease due to 
aging airplanes and adequate wire separation design on Model 767 
airplanes. Boeing added that the estimated costs in the NPRM do not 
take into account the costs of compliance for passenger airplanes 
without FRM installed.
    The FAA disagrees with the commenter's request. The FAA did not 
base its unsafe condition determination on fleet risk but instead on 
individual risk. This is discussed in detail in the response to 
comments in the SNPRM for Docket No. FAA-2012-0187, under the heading 
``Request To Withdraw NPRM (77 FR 12506, March 1, 2012): Unjustified by 
Risk.'' Therefore, the age of the airplane and its current production 
stoppage do not affect the determination that an unsafe condition still 
exists on an individual airplane.
    The NPRM for this proposed rule did contain a cost estimate for 
passenger airplanes that was based on the estimate provided by Boeing 
for the Model 757 and Model 767 airplanes, which have an FQIS of 
similar design. The FAA notes that Boeing asserted that the cost to 
operators of modifying an airplane's FQIS to be fully compliant with 
the airworthiness standards would be similar to the cost of installing 
Boeing's NGS flammability reduction system. Based on that, Boeing 
requested that the FAA agree to not require Boeing to develop service 
information for a fully compliant FQIS modification. However, the FAA 
used Boeing's estimate of the cost to modify the Model 757 and Model 
767 FQIS to a fully part-25-compliant configuration to provide the 
estimated costs in the NPRM, based on an assumption that the cost for 
Model 747 airplanes would be similar. At the time, Boeing concurred 
with this estimate. This is discussed in detail in the response to 
comments in the SNPRM for Docket No. FAA-2012-0187. The FAA has not 
changed this AD regarding this issue.

Request To Withdraw NPRM: Underestimated Parts Cost

    FedEx stated that the proposed rule underestimates costs for the 
required actions. Specifically, FedEx noted that Boeing estimates the 
part kit cost for installing NGS to be $440,000, not $200,000 as stated 
in the proposed AD. FedEx stated that the NGS is a very expensive 
system, which adds undue burden on operators. FedEx claimed that the 
proposed rule is therefore unjustified.
    The FAA agrees to clarify. The FAA's cost estimate in the NPRM was 
not for installation of NGS, but rather was for an FQIS modification to 
bring the FQIS into compliance with the applicable regulations. The 
estimated parts cost and work hours used were those supplied by Boeing 
and Goodrich Aerospace for such a modification. However, if an operator 
chooses to install an NGS in lieu of accomplishing the modification, 
the FAA acknowledges the parts cost would likely be higher for that 
operator. The FAA has not changed this AD regarding this issue.

Request To Require Cargo Airplane Option for All Airplanes

    Boeing requested that the NPRM be revised to make the alternative 
actions for cargo airplanes specified in paragraph (h) of the proposed 
AD applicable to all airplanes, including passenger airplanes with FRM 
not installed due to differences in foreign regulations. In addition, 
Boeing requested that the actions specified in paragraph (h) of the 
proposed AD become the primary means of compliance for all airplanes, 
not an alternative method of compliance for some airplanes.
    The FAA disagrees with the commenter's request. As discussed in the 
comment response in the SNPRM for Docket No. FAA-2012-0187, under the 
heading ``Requests To Withdraw NPRM (77 FR 12506, March 1, 2012) Based 
on Applicability'' the FAA does not consider the alternative action for 
cargo airplanes allowed by this AD to provide an adequate level of 
safety for passenger airplanes. The FAA is willing to accept a higher 
level of individual flight risk exposure for cargo flights that are not 
fail-safe due to the absence of passengers and the resulting 
significant reduction in occupant exposure on a cargo airplane versus a 
passenger airplane, and due to relatively low estimated individual 
flight risk that would exist on a cargo airplane after the corrective 
actions are taken. The FAA has not changed this AD regarding this 
issue.

Request To Change Compliance Time

    A4A/CAA, FedEx, Japan Airlines (JAL), and Air Transport 
International requested that the FAA extend the compliance time for the 
modifications specified in paragraphs (g) and (h)(2) of the proposed AD 
to 72 months. A4A/CAA stated that the compliance time should match that 
of AD 2016-07-07 because the unsafe condition and corrective actions 
are similar. Air Transport International noted the longer compliance 
time would provide additional time for passenger-to-freighter 
conversions to incorporate a currently unreleased service bulletin into 
any supplemental type certificate (STC). A4A/CAA stated that although

[[Page 62998]]

service information was not yet available, the compliance time should 
align with major maintenance schedules, but should be not less than 72 
months after service information is available.
    Conversely, NATCA recommended that the FAA reject requests for a 
compliance time longer than 5 years as proposed in the NPRM. Assuming 
final rule issuance in 2016, NATCA estimated that a 5-year compliance 
time would result in required compliance by 2021--25 years after the 
TWA Flight 800 fuel tank explosion that led to the requirements in SFAR 
88, and 20 years after issuance of SFAR 88.
    The FAA agrees with the commenters' requests to extend the 
compliance time, and disagrees with NATCA's request. The FAA received 
similar requests to extend the compliance time from several commenters 
regarding the NPRMs for the FQIS modification on other airplanes. The 
FAA disagrees with establishing a compliance time based on issuance of 
the service information that is not yet approved or available. The FAA 
has determined that a 72-month compliance time is appropriate and will 
provide operators adequate time to prepare for and perform the required 
modifications without excessive disruption of operations. The FAA has 
determined that the requested moderate increase in compliance time will 
continue to provide an acceptable level of safety. The FAA has changed 
paragraphs (g) and (h)(2) of this AD accordingly.

Request To Extend Repetitive BITE Check Interval

    Air Transport International and All Nippon Airways (ANA) requested 
that paragraph (h)(1) of the proposed AD be revised to extend the 
repetitive check interval for the BITE checks. Air Transport 
International requested that the repetitive interval be extended to 750 
flight hours to match the repetitive interval specified in AD 2016-07-
07. ANA noted that an interval of 750 flight hours will allow the check 
to be done during A-check intervals.
    The FAA agrees to extend the repetitive check interval to 750 
flight hours. The FAA intended to propose a 750 flight hour interval, 
but inadvertently specified 650 flight hour intervals in the proposed 
AD. The FAA has revised paragraph (h)(1) of this AD to specify 
repetitive intervals of 750 flight hours.

Request To Clarify Actions in Paragraph (h)(1) of the Proposed AD

    ANA requested that the FAA clarify the actions specified in 
paragraph (h)(1) of the proposed AD. ANA noted there are two actions 
(record the existing fault code stored in the FQIS processor prior to 
doing the BITE check of the FQIS and do a BITE check of the FQIS) that 
must be done using Boeing Service Bulletin 767-28-0118, dated July 15, 
2014. ANA stated Boeing Service Bulletin 767-28-0118, dated July 15, 
2014, does not contain specific instructions to record existing fault 
codes. ANA noted that recording existing fault codes can be done using 
existing maintenance tasks. ANA asked if recording the existing fault 
codes must be done using Boeing Service Bulletin 767-28-0118, dated 
July 15, 2014, and if so, requested that Boeing Service Bulletin 767-
28-0118, dated July 15, 2014, be revised to address the AD action.
    The FAA agrees to clarify. Boeing Service Bulletin 767-28-0118, 
dated July 15, 2014, contains notes in Parts 4 and 5 of the 
Accomplishment Instructions stating that operators should record the 
existing faults prior to initiating the BITE check of the processor. 
However, those notes don't include specific procedures. Operators may 
use accepted procedures, including existing maintenance tasks, to 
comply with the requirements to record existing fault codes. No change 
to this AD is necessary.

Request To Clarify Whether Certain Actions Can Be Done Without 
Obtaining an Alternative Method of Compliance (AMOC)

    ABX AIR requested that the FAA clarify whether it can perform the 
repetitive checks specified in paragraph (h)(1) of the proposed AD. ABX 
AIR noted that it operates airplanes converted to a cargo configuration 
using an STC, so its airplanes are not included in the effectivity of 
Boeing Service Bulletin 767-28-0118, dated July 15, 2014. ABX AIR asked 
if it could still do the repetitive checks in accordance with Boeing 
Service Bulletin 767-28-0118, dated July 15, 2014, without obtaining an 
AMOC.
    The FAA agrees to clarify. The FAA determined that the BITE check 
procedures in the service bulletin are applicable to all Boeing 767 
airplanes. Therefore, it is acceptable to use the procedures specified 
in the service information even on airplanes that are not listed in the 
effectivity of Boeing Service Bulletin 767-28-0118, dated July 15, 
2014.

Request To Provide Dispensation for Airplanes To Be Retired

    British Airways (BA) requested that the proposed AD be revised to 
provide dispensation for aircraft to be retired, which would not be 
prohibitive for operators. BA stated that the only Boeing solution 
available to comply with the proposed AD is to install an NGS. BA 
further stated that NGS is not mandatory for operators outside of the 
U.S. and is a high cost, high work-hour modification.
    The FAA infers that the commenter is requesting an extension of the 
compliance time for airplanes that will be retired by a certain date or 
for the AD to exclude those airplanes. The FAA notes that the commenter 
did not propose a specific period of additional time for operation 
without addressing the unsafe condition, and did not propose any 
specific alternative corrective actions. The FAA's understanding is 
that British Airways no longer operates Model 767 airplanes. The FAA 
also notes that this AD does not require installing an NGS; this AD 
requires an FQIS modification. If the commenter or another operator 
wishes to make a specific proposal, they can submit that proposal using 
the AMOC process specified in paragraph (j) of this AD. The FAA has not 
changed this AD regarding this issue.

Request To State That an Exemption Is Required

    Boeing requested that paragraph (h) of the proposed AD be revised 
to state that an exemption is required to accomplish the specified 
actions. Boeing stated that the FAA has identified that the BITE 
procedure and wire separation design changes specified in the proposed 
AD are not sufficient for compliance to 14 CFR 25.981(a) at the FQIS 
level. Boeing stated that an exemption is therefore needed prior to 
approval of the related design change.
    The FAA agrees to clarify. The BITE check is not a type design 
change or alteration, so no exemption from the airworthiness standards 
is required for that action. The FAA design data approval of any 
partial wire separation modification would require an exemption. That 
exemption would be obtained by the party seeking approval of the 
alteration data, and no further exemption would be required for the 
party using that data to alter an aircraft. Obtaining such an exemption 
would be part of the certification process for such a change, so the 
FAA does not find it necessary to include such information in paragraph 
(h) of this AD. In addition, some parties may choose to comply with the 
AD using a design change that fully complies with the airworthiness 
standards. The FAA also notes that the commenter appears to 
misunderstand why an exemption is needed for the required modification. 
The exemption is

[[Page 62999]]

needed because, even with the modification, the FQIS does not comply 
with 14 CFR 25.901(c) and 14 CFR 25.981(a). The exemption does not 
authorize evaluation of a partial system for compliance with the system 
level requirement. The FAA has not changed this AD regarding this 
issue.

Request To Clarify Certification Basis for Modification Requirements

    NATCA recommended that the FAA revise paragraph (g) of the proposed 
AD to clearly state that the required FQIS design changes must comply 
with the fail-safe requirements of 14 CFR 25.901(c), as amended by 
amendment 25-46 (43 FR 50597, October 30, 1978); and 14 CFR 25.981(a) 
and (b), as amended by amendment 25-102; NATCA added that these 
provisions are required by SFAR 88.
    The FAA does not agree to change paragraph (g) of this AD. While 
the FAA agrees that modifications to comply with paragraph (g) should 
be required to comply with the referenced regulations, that requirement 
already exists in 14 CFR part 21. No change to this AD is necessary.

Request To Require Modification on All Production Airplanes

    NATCA recommended that the FAA require designs that comply with 14 
CFR 25.901(c) and 25.981(a)(3) on all newly produced transport 
airplanes. NATCA stated that continuing to grant exemptions to 14 CFR 
25.901(c), as amended by amendment 25-40 (42 FR 15042, March 17, 1977); 
and 14 CFR 25.981(a)(3), as amended by amendment 25-102; has allowed 
continued production of thousands of airplanes with this known unsafe 
condition.
    The FAA disagrees with the commenter's request. The recommendation 
to require production airplanes to fully comply with 14 CFR 25.901(c) 
and 14 CFR 25.981(a)(3) is outside the scope of this rulemaking. The 
FAA has implemented requirements for all large transport airplanes 
produced after September 2010 to include flammability reduction methods 
for tanks that would otherwise be high-flammability fuel tanks. Boeing 
incorporated this change into the Model 767 series airplanes that are 
still in production and the FAA has excluded those airplanes from the 
applicability of this AD. The FAA has not changed this final rule 
regarding this issue.

Request To Exclude Certain Airplanes

    United Airlines (UAL) requested that the FAA revise the proposed AD 
to exclude airplanes that are affected by 14 CFR 121.1117. UAL noted 
that the FRM required by 14 CFR 121.1117 will have been installed on 
all affected airplanes in passenger configuration by December 26, 2018. 
UAL suggested that the FAA either delete paragraph (g) of the proposed 
AD or make paragraph (g) of the proposed AD applicable only to 
airplanes in a cargo configuration that do not have an FRM installed 
and non-U.S.-registered airplanes that do not have to comply with FRM 
requirements.
    The FAA disagrees with the commenter's request. There are other 
passenger-carrying airplanes operated under 14 CFR part 91 that are not 
required to install FRM. (The requirement to install FRM on all 
passenger-carrying airplanes operated by air carriers is in 14 CFR 
121.1117.) The FAA notes that foreign air carriers may not have to 
comply with that requirement or similar requirements of their own civil 
aviation authority. EASA, for example, has chosen not to require FRM to 
be retrofitted to in-service airplanes. The proposed AD is intended to 
require any Model 767 series passenger airplane that does not have FRM, 
regardless of the rules under which it is operated, to address the FQIS 
latent-plus-one unsafe condition with a corrective action that fully 
complies with the FAA airworthiness standards. This requirement 
fulfills the FAA's International Civil Aviation Organization (ICAO) 
obligation to address unsafe conditions on all of the aircraft 
manufactured by the state of design, not just those aircraft whose 
operation is under the jurisdiction of the state of design. The FAA has 
not changed this AD regarding this issue.

Request To Provide Cost-Effective Method of Compliance

    BA and JAL requested that the FAA encourage Boeing to provide a 
cost-effective method of compliance for passenger airplanes. JAL noted 
that Boeing expects the NGS installation to be an AMOC for the proposed 
AD. However, JAL and BA noted that the majority of non-FAA operators 
are not required to retrofit the NGS system. The commenters requested 
that the FAA encourage Boeing to develop an acceptable cost-effective 
method of compliance that does not require installation of an NGS.
    The FAA agrees that the lack of service information for FQIS 
modifications makes it difficult to assess the required work to modify 
the FQIS, and acknowledges the high cost of NGS. However, the FAA 
disagrees with the commenters' request. For passenger-carrying 
airplanes, the cost per airplane of providing a modification of the 
FQIS that fully complies with the airworthiness standards was estimated 
by Boeing and their FQIS vendor (Goodrich) prior to the issuance of the 
NPRM to be comparable to the cost of installing NGS. Based on that cost 
estimate, Boeing proposed that they not be required to develop a fully 
compliant FQIS modification for passenger airplanes because it would 
not provide significant savings to operators and NGS would provide a 
greater safety benefit. The FAA agreed. The FAA's understanding is that 
Boeing's current position is the same, and that they do not plan to 
develop a fully compliant FQIS modification for passenger airplanes to 
address paragraph (g) of this AD. However, if service information is 
developed, approved, and available in the future, operators may request 
approval under the provisions of paragraph (j) of this AD to use 
approved service instructions as an AMOC for the requirements of this 
AD, or the FAA may approve the service information as a global AMOC for 
this AD. In addition, Boeing has issued Service Bulletin 767-28-0122, 
Revision 1, dated February 26, 2020, for all-cargo airplanes, and the 
FAA has revised paragraph (h)(2) of this AD to specify that Boeing 
Service Bulletin 767-28-0122, Revision 1, dated February 26, 2020, is 
an acceptable method of compliance. This revision includes adding 
paragraphs (h)(2)(i) and (ii) of this AD. The FAA has also added 
paragraph (i) of this AD to provide credit for Boeing Service Bulletin 
767-28-0122, dated October 11, 2016, and redesignated subsequent 
paragraphs accordingly. The FAA has also revised the Estimated Costs 
for Alternative Actions table in this final rule to include the 
estimated costs for the wire separation modification specified in 
Boeing Service Bulletin 767-28-0122, Revision 1, dated February 26, 
2020, if operators choose to comply using that method.
    The FAA notes that this cost estimate is based on data provided in 
Boeing Service Bulletin 767-28-0122, dated October 11, 2016, while the 
cost estimate provided for a modification using methods approved in 
accordance with the procedures specified in paragraph (h)(2)(i) of this 
AD (paragraph (h)(2) of the proposed AD) is based on data provided by 
the manufacturer for Model 757 and 767 airplanes. The FAA had 
previously determined, as specified in the NPRM, that the work involved 
for the cargo airplane wire separation modification would take 230 
work-hours. Boeing has since provided an updated estimate of 74 work-
hours for the alternative modification for cargo airplanes. The FAA has 
revised the cost

[[Page 63000]]

estimate for the modification accordingly in this final rule.

Request To Require Design Changes From Manufacturers

    NATCA recommended that the FAA follow the agency's compliance and 
enforcement policy to require manufacturers to develop the necessary 
design changes soon enough to support operators' ability to comply with 
the proposed requirements. NATCA noted that SFAR 88 required 
manufacturers to develop all design changes for unsafe conditions 
identified by their SFAR 88 design reviews by December 2002, or within 
an additional 18 months if the FAA granted an extension.
    The FAA acknowledges the commenter's concerns. However, any 
enforcement action is outside the scope of this rulemaking. The FAA has 
not changed this final rule regarding this issue.

Request To Address Unsafe Condition on All Fuel Tanks

    NATCA recommended that the FAA require design changes that 
eliminate unsafe FQIS failure conditions on all fuel tanks on the 
affected models, regardless of fuel tank location or the percentage of 
time the fuel tank is flammable. NATCA referred to four fuel tank 
explosions in low-flammability exposure time fuel tanks identified by 
the FAA during FTFR rulemaking. NATCA stated that neither FRM nor 
alternative actions for cargo airplanes (e.g., BITE checks (checks of 
built-in test equipment) followed by applicable repairs before further 
flight and modification of the center fuel tank FQIS wiring within 60 
months) would bring the airplane into full regulatory compliance. NATCA 
added that the combination of failures described in the NPRM meets the 
criteria for ``known combinations'' of failures that require corrective 
action in FAA Policy Memorandum ANM100-2003-112-15.
    The FAA disagrees with the commenter's request. The FAA has 
determined that according to Policy Memorandum ANM100-2003-112-15, the 
failure condition for the airplanes affected by this AD should not be 
classified as a ``known combination.'' While the FQIS design 
architecture is similar to that of the early Boeing Model 747 
configuration that is suspected of contributing to the TWA Flight 800 
fuel tank explosion, significant differences exist in the design of 
FQIS components and wire installations between the affected The Boeing 
Company models and the early Model 747 airplanes such that the intent 
of the ``known combinations'' provision for low-flammability fuel tanks 
in the policy memorandum is not applicable. Therefore, this AD affects 
only the identified Boeing airplanes with high-flammability exposure 
time fuel tanks, as specified in paragraph (c) of this AD. The FAA 
provided a detailed response to similar comments in the preamble of the 
final rule for AD 2016-07-07. The FAA has not changed this final rule 
regarding this issue.

Clarification of Applicability

    The FAA has added paragraph (c)(3) to this AD to clarify that 
airplanes equipped with an ignition mitigation means (IMM) approved by 
the FAA as compliant with certain regulations are excluded from this 
AD. The FAA intended for airplanes with compliant IMM to be excluded 
from the actions required by this AD. The FAA has determined that the 
installation of an approved IMM provides a level of risk reduction at 
least as great as that provided by FRM and adequately addresses the 
unsafe condition.

Clarification of BITE Check Compliance Time

    The FAA has revised paragraph (h)(1) of this AD to clarify the 
compliance time for the BITE check relative to the requirement to 
record the fault codes. The FAA recognized that operators might 
interpret the proposed requirements for alternative actions for cargo 
airplanes as allowing additional flights prior to performing the BITE 
check after first recording the fault codes. The FAA intended for 
operators to perform the BITE check immediately after recording the 
fault codes to address both the fault codes that exist prior to 
performing the BITE check and any new codes that are identified during 
the BITE check.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety and the public interest 
require adopting this final rule with the changes described previously 
and minor editorial changes. The FAA has determined that these minor 
changes:
     Are consistent with the intent that was proposed in the 
NPRM for addressing the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    The FAA also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this final 
rule.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Service Bulletin 767-28-0118, dated July 
15, 2014. This service information describes procedures for a BITE 
check of the FQIS.
    The FAA also reviewed Boeing Service Bulletin 767-28-0122, Revision 
1, dated February 26, 2020. This service information describes 
procedures for modifying the airplane by separating FQIS wiring that 
runs between the FQIS processor and the center tank wing spar 
penetrations from other airplane wiring and applicable corrective 
actions (including correcting loop resistance and electrical bonding 
resistance).
    This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 261 airplanes of U.S. 
registry. This estimate includes 255 cargo airplanes; 4 private, 
business/corporate/executive, or government airplanes; and 2 
experimental airplanes. The FAA estimates the following costs to comply 
with this AD:

                                        Estimated Costs: Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
              Action                        Labor cost            Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
Modification......................  1,200 work-hours x $85           $200,000         $302,000      $78,822,000
                                     per hour = $102,000.
----------------------------------------------------------------------------------------------------------------


[[Page 63001]]


                                      Estimated Costs: Alternative Actions
----------------------------------------------------------------------------------------------------------------
              Action                        Labor cost                 Parts cost           Cost per  product
----------------------------------------------------------------------------------------------------------------
BITE check........................  18 work-hours x $85 per     $0.....................  $1,530 per check.
                                     hour = $1,530 per check..
Wire separation (using service      Up to 289 work-hours x $85  Up to $51,970..........  Up to $76,535.
 information).                       per hour = Up to $24,565.
Wire separation...................  74 work-hours x $85 per     $10,000................  $16,290.
                                     hour = $6,290.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2020-18-16 The Boeing Company: Amendment 39-21237; Docket No. FAA-
2016-6141; Product Identifier 2015-NM-048-AD.

(a) Effective Date

    This AD is effective November 10, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 767-200, -300, -
300F, and -400ER series airplanes, certificated in any category, 
excluding airplanes identified in paragraphs (c)(1) through (3) of 
this AD.
    (1) Airplanes on which the center auxiliary tank consists only 
of the spaces between the side of body rib 0 and rib 3 of the left 
and right wings (i.e., the wing center structural box is a dry bay 
and is not part of the fuel tank).
    (2) Airplanes equipped with a flammability reduction means (FRM) 
approved by the FAA as compliant with the fuel tank flammability 
reduction (FTFR) requirements of 14 CFR 25.981(b) or 26.33(c)(1).
    (3) Airplanes equipped with an ignition mitigation means (IMM) 
approved by the FAA as compliant with the FTFR requirements of 14 
CFR 25.981(c) or 26.33(c)(2).

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by the FAA's analysis of the Model 767 fuel 
system reviews conducted by the manufacturer. The FAA is issuing 
this AD to prevent ignition sources inside the center fuel tank, 
which, in combination with flammable fuel vapors, could result in a 
fuel tank explosion and consequent loss of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Modification

    Within 72 months after the effective date of this AD, modify the 
fuel quantity indicating system (FQIS) to prevent development of an 
ignition source inside the center fuel tank due to electrical fault 
conditions, using a method approved in accordance with the 
procedures specified in paragraph (j) of this AD.

(h) Alternative Actions for Cargo Airplanes

    For airplanes used exclusively for cargo operations: As an 
alternative to the requirements of paragraph (g) of this AD, do the 
actions specified in paragraphs (h)(1) and (2) of this AD. To 
exercise this option, operators must perform the first inspection 
required under paragraph (h)(1) of this AD within 6 months after the 
effective date of this AD. To exercise this option for airplanes 
returned to service after conversion of the airplane from a 
passenger configuration to an all-cargo configuration more than 6 
months after the effective date of this AD, operators must perform 
the first inspection required under paragraph (h)(1) of this AD 
prior to further flight after the conversion.
    (1) Within 6 months after the effective date of this AD, record 
the existing fault codes stored in the FQIS processor and before 
further flight thereafter do a BITE check (check of built-in test 
equipment) of the FQIS, in accordance with the Accomplishment 
Instructions of Boeing Service Bulletin 767-28-0118, dated July 15, 
2014. If any nondispatchable fault code is recorded prior to the 
BITE check or as a result of the BITE check, before further flight, 
do all applicable repairs and repeat the BITE check until a 
successful test is performed with no nondispatchable faults found, 
in accordance with Boeing Service Bulletin 767-28-0118, dated July 
15, 2014. Repeat these actions thereafter at intervals not to exceed 
750 flight hours. Modification as specified in paragraph (h)(2) of 
this AD does not terminate the repetitive BITE check requirement of 
this paragraph.
    (2) Within 72 months after the effective date of this AD, do the 
actions specified in paragraph (h)(2)(i) or (ii) of this AD.
    (i) Modify the airplane by separating FQIS wiring that runs 
between the FQIS processor and the center tank wing spar 
penetrations, including any circuits that might pass through a main 
fuel tank, from other airplane wiring that is not intrinsically safe 
using methods approved in accordance with the procedures specified 
in paragraph (j) of this AD.
    (ii) Modify the airplane by separating FQIS wiring that runs 
between the FQIS processor and the center tank wing spar 
penetrations,

[[Page 63002]]

including any circuits that might pass through a main fuel tank, 
from other airplane wiring that is not intrinsically safe, and do 
all applicable corrective actions, in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 767-28-0122, 
Revision 1, dated February 26, 2020. Do all applicable corrective 
actions before further flight.

(i) Credit for Previous Actions

    This paragraph provides credit for the actions specified in 
paragraph (h)(2)(ii) of this AD, if those actions were performed 
before the effective date of this AD using Boeing Service Bulletin 
767-28-0122, dated October 11, 2016.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (k)(1) of this AD. Information may be 
emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO Branch, FAA, to make those findings. To be approved, the repair 
method, modification deviation, or alteration deviation must meet 
the certification basis of the airplane, and the approval must 
specifically refer to this AD.
    (4) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(j)(4)(i) and (ii) apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(k) Related Information

    (1) For more information about this AD, contact Jon Regimbal, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3557; email: Jon.Regimbal@faa.gov.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (l)(3) and (4) of this AD.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Service Bulletin 767-28-0118, dated July 15, 2014.
    (ii) Boeing Service Bulletin 767-28-0122, Revision 1, dated 
February 26, 2020.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability 
of this material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on August 26, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-21997 Filed 10-5-20; 8:45 am]
BILLING CODE 4910-13-P


