```

[Federal Register Volume 81, Number 122 (Friday, June 24, 2016)]
[Rules and Regulations]
[Pages 41200-41208]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-14454]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 25, 121, and 129

[Docket No.: FAA-2014-0500; Amdt. Nos. 25-142, 21-376, and 129-53]
RIN 2120-AK30

Fuel Tank Vent Fire Protection

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is amending certain airworthiness regulations for 
transport category airplanes to require fuel tank designs that prevent 
a fuel tank explosion caused by the propagation of flames, from 
external fires, through the fuel tank vents. This final rule requires a 
delay of two minutes and thirty seconds between exposure of external 
fuel tank vents to ignition sources and explosions caused by 
propagation of flames into the fuel tank, thus increasing the time 
available for passenger evacuation and emergency response. These 
amendments apply to applications for new type certificates and certain 
applications for amended or supplemental type certificates. The 
amendments also require certain airplanes produced in the future and 
operated by air carriers to meet the new standards.

DATES: Effective August 23, 2016. The compliance date for the 
requirements in Sec.  25.975 is August 23, 2016. The compliance date 
for the requirements in Sec. Sec.  121.1119 and 129.119 is August 23, 
2018.

ADDRESSES: For information on where to obtain copies of rulemaking 
documents and other information related to this final rule, see ``How 
to Obtain Additional Information'' in the SUPPLEMENTARY INFORMATION 
section of this document.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning 
this action, contact Mike Dostert, Propulsion and Mechanical Systems 
Branch, ANM-112, Transport Airplane Directorate,

[[Page 41201]]

Aircraft Certification Service, Federal Aviation Administration, 1601 
Lind Ave SW., Renton, WA 98057-3356; telephone (425) 227-2132; 
facsimile (425) 227-1149; email Mike.Dostert@faa.gov.

SUPPLEMENTARY INFORMATION: 

Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in 
Title 49 of the United States Code. 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.
    This rulemaking is promulgated under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
Requirements.'' Under that section, the FAA is charged with promoting 
safe flight of civil aircraft in air commerce by prescribing 
regulations and minimum standards, for the design and performance of 
aircraft, that the Administrator finds necessary for safety in air 
commerce. This regulation is within the scope of that authority. It 
prescribes new safety standards for the design and operation of 
transport category airplanes.

I. Overview of Final Rule

A. General

    The FAA is amending title 14, Code of Federal Regulations (14 CFR) 
parts 25, 121, and 129 as described below. The intent of this rule is 
to prevent fuel tank explosions caused by ignition from external 
ignition sources of fuel vapor either contained in vapor spaces \1\ or 
exiting from vapor spaces through the fuel tank vent outlets. Potential 
external ignition sources include, but are not limited to, ground 
handling equipment, fuel fires that result from refueling spills, or 
ground fires that follow a survivable crash landing in which the fuel 
tank and the vent system remain intact. Means to prevent or delay the 
propagation of flame \2\ from external sources into the fuel tank 
through the fuel tank vent system \3\ would also prevent or delay fuel 
tank explosions following certain accidents. These means include flame 
arrestors or fuel tank inerting. This prevention or delay would provide 
additional time for the safe evacuation of passengers from the airplane 
and for emergency personnel to provide assistance.
---------------------------------------------------------------------------

    \1\ A vapor space is any portion of the airplane fuel tanks and 
the fuel tank vent system that, if such tanks and system held any 
fuel, could contain fuel vapor.
    \2\ Flame propagation is the spread of a flame in a combustible 
environment outward from the point at which the combustion started.
    \3\ A fuel tank vent system is a system that ventilates fuel 
vapor from the airplane fuel tanks to the atmosphere. A fuel tank 
vent system ensures that the air and fuel pressure within the fuel 
tank stay within structural limits required by Sec.  25.975 (a).
---------------------------------------------------------------------------

    This rule applies to applications for new type certificates and 
applications for amended or supplemental type certificates on 
significant product-level change projects in which Sec.  25.975, ``Fuel 
tank vents and carburetor vapor vents,'' is applicable to a changed 
area. Additionally, a new operating requirement in both 14 CFR part 
121, ``Operating Requirements: Domestic, Flag, and Supplemental 
Operations,'' and 14 CFR part 129, ``Operations: Foreign Air Carriers 
and Foreign Operators of U.S.-Registered Aircraft Engaged in Common 
Carriage,'' applies to airplanes that are issued an original 
airworthiness certificate after a specified date. The FAA is not 
requiring retrofit of the existing fleet.
    Concurrent with the publication of this rule, the FAA is publishing 
Advisory Circular (AC) 25.975-1 that provides guidance concerning means 
of compliance with the revised Sec.  25.975.\4\
---------------------------------------------------------------------------

    \4\ AC 25.975-1 is available on the FAA Web site at http://www.faa.gov/regulations_policies/advisory_circulars/.
---------------------------------------------------------------------------

II. Background

A. Statement of the Problem

    This rulemaking addresses the problem of fuel tank explosions 
caused by flame propagation from fires outside the airplane reaching 
the fuel tank through the fuel tank vents. Fires outside of the 
airplane fuel tanks can be caused by ignition of fuel spilled during 
refueling, fuel and oil spillage from engines that separate from the 
airplane following an accident, or fuel leaking from damaged airplane 
fuel tanks. In some cases, external fires have ignited fuel vapors that 
have exited the fuel tank vents, resulting in flames traveling back 
through the vent lines into the fuel tank and causing fuel tank 
explosions. These explosions have caused passenger fatalities and 
prevented emergency personnel from assisting survivors.
    Existing requirements address some ignition sources. Airworthiness 
standards in Sec.  25.981 for preventing fuel system explosions include 
requirements to prevent ignition sources inside the fuel tanks caused 
by failures of airplane components or external heating of the fuel tank 
walls. The fuel tank venting standards in Sec.  25.975 include 
requirements to ensure fuel tank structural integrity following 
failures of the refueling system that could result in overfilling of 
the fuel tanks, or clogging of the vents due to ice. Section 25.954, 
``Fuel system lightning protection,'' requires that fuel tank vents be 
designed and arranged to prevent the ignition of fuel vapor within the 
system by lightning strikes. These regulations, however, do not address 
the risk posed by flame from external ignition sources entering the 
fuel tank through the fuel vents.
    Most new type designs and transport category airplanes currently in 
production include flame arrestors or other means to prevent flame 
propagation through the fuel vent lines into the fuel tanks. However, 
some models of newly manufactured airplanes produced under older type 
certificates and introduced into the U.S. fleet do not have a means of 
preventing fuel tank explosions caused by external ignition sources. In 
addition, lack of a specific part 25 regulation to address this has 
resulted in some applicants completing initial airplane designs and 
applying for a U.S. type certificate without having accounted for the 
risk of flame propagation through fuel vent lines.

B. History

    These amendments stem from an industry study of potential post-
crash survivability and FAA airworthiness actions in response to 
accidents that involved fuel tank explosions. The FAA has issued 
airworthiness directives (ADs) that require flame arrestors, or 
verification of their functionality, on several airplane models. In 
1999, following a review of fuel tank explosions on older designs, the 
FAA issued an AD \5\ mandating incorporation of flame arrestors on 
Boeing Model 737 airplanes. That AD action eliminated the risk of fuel 
tank explosions from flames entering the fuel tanks through the fuel 
tank vents on early models of the Boeing 737. More recently, in 2008, 
the FAA issued an AD requiring installation of flame arrestors on the 
Lockheed Model 382.\6\
---------------------------------------------------------------------------

    \5\ AD 99-03-04 BOEING: Amendment 39-11018; Docket 98-NM-50-AD 
(effective March 9, 1999).
    \6\ AD 2011-15-02 LOCKHEED: Amendment 39-16749; Docket No. FAA-
2010-1305 (effective August 19, 2011).
---------------------------------------------------------------------------

    The Special Aviation Fire and Explosion Reduction (SAFER) Advisory 
Committee \7\ examined transport category airplane post-crash fires and 
determined that four fuel tank explosions resulting from post-crash 
fires could have been avoided if flame arrestors or surge tank 
explosion

[[Page 41202]]

suppression systems \8\ had been installed in the airplane fuel tank 
vents.\9\ The SAFER Committee examined methods of preventing fuel tank 
explosions following impact in survivable accidents, including 
controlling the fuel tank flammability using nitrogen inerting systems, 
using fire suppression systems, and installation of flame arrestors.
---------------------------------------------------------------------------

    \7\ Special Aviation Fire and Explosion Reduction (SAFER) 
Advisory Committee Final Report, Volume 1, FAA-ASF-80-4, dated June 
26, 1978, through June 26, 1980. A copy of this report has been 
placed in the docket of this proceeding.
    \8\ Boeing developed surge tank explosion suppression systems 
that were installed on some Boeing airplanes to prevent a lightning 
strike from igniting fuel vapor in the fuel tank vent system. These 
systems used light sensors that activated the discharge of fire 
suppression agent into the vent surge tank to prevent the fire from 
traveling through the vents into the airplane fuel tanks.
    \9\ SAFER Report, page 49, Figure 3.
---------------------------------------------------------------------------

    The SAFER Committee determined the most practical means of 
preventing post-crash fuel tank explosions was the use of flame 
arrestors. Flame arrestors stop the flame from traveling through the 
fuel tank vents by quenching the flame. Flame arrestors are typically 
made of numerous small stainless steel passages that remove heat from 
the flame so it dies out before passing into the fuel tank. This delays 
propagation of ground fires into the fuel tank and subsequent 
explosions, providing additional time for the safe evacuation of 
passengers. The two flame arrestors installed on a typical transport 
airplane weigh approximately 2 to 4 pounds each.
    In 1995, based on the SAFER Committee report, the FAA issued an 
NPRM entitled, ``Fuel System Vent Fire Protection,'' (60 FR 6632), 
dated February 2, 1995. That NPRM proposed to require 5 minutes of fuel 
tank vent fire protection in new type designs for transport category 
airplanes, and amend certain operating rules to require retrofit of the 
existing fleet of transport category airplanes. The FAA received 
comments on the NPRM that questioned the proposed 5-minute standard and 
the accuracy of the economic analysis related to the proposed retrofit 
requirement. Comments also suggested that the FAA should develop 
additional guidance, in the form of an AC, to provide an acceptable 
method of qualifying flame arrestors as a means of meeting the proposed 
requirement.
    To address those 1995 comments, the FAA obtained additional cost 
information from component suppliers, and drafted an AC that included a 
means of demonstrating compliance. That means of compliance was the 
installation of fuel tank vent flame arrestors that would prevent 
propagation of flames through the fuel tank vents into the fuel tanks 
for a minimum of 2 minutes and 30 seconds. In 2001, the FAA tasked its 
Aviation Rulemaking Advisory Committee (ARAC) to review a draft final 
rule, including the FAA's proposed disposition of public comments, and 
the draft AC. In 2002, due to the ARAC tasking, the FAA published in 
the Federal Register a notice of withdrawal of the NPRM that had been 
published in 1995. Because of industry resource issues and FAA 
rulemaking prioritization activities, however, no work was done on 
these ARAC taskings. The FAA published a withdrawal of the tasks on 
June 21, 2004.
    As an alternative, the FAA developed a strategy for a number of 
rulemaking projects that had been tasked to the ARAC. In 2005, the FAA 
issued a letter \10\ to the head of the Transport Airplane and Engine 
Issues Group describing the agency's intent to use the process under 14 
CFR 21.21 of finding an unsafe design feature to address the need to 
prevent flame propagation through fuel tank vents. Since 2005, the FAA 
has used issue papers applicable to specific certification projects, 
which have resulted in the inclusion of flame arrestors in the design 
of new type certificated airplanes.
---------------------------------------------------------------------------

    \10\ John Hickey, Director, Aircraft Certification Service, to 
Craig Bolt, Assistant Chair, Transport Airplane and Engine Issues 
Group, 14 June 2005.
---------------------------------------------------------------------------

    Prior to the FAA's issuance of the 2005 letter, however, many 
manufacturers had followed industry recommendations and voluntarily 
introduced flame arrestors into their new type designs.
    However, some business jets and smaller transport category 
airplanes do not incorporate flame arrestors or other means to prevent 
flame propagation into the fuel tanks. Also, some airplanes operating 
under 14 CFR part 121 do not have such means, including older models 
like the DC-9 and MD-80, and all DHC-8 turboprops and Canadair Regional 
Jets, both of which are still in production. This amendment addresses 
those airplanes.
    As discussed in the NPRM, the FAA based the 2 minute and 30 
seconds, in part, on previous Aerospace Industries Association (AIA) 
comments to the NPRM the FAA published in 1995 that proposed a 5-minute 
standard. AIA stated that flame arrestors in production at that time 
could not meet the proposed 5-minute standard and that 5 minutes was 
overly conservative. Based on those comments, the FAA reviewed the 
capability and the service experience of in-production designs, as well 
as the conservatism of the flame-holding test methods used for 
evaluating flame arrestor performance. In 1996, the FAA determined that 
a 2 minute and 30 second capability allowed flame arrestors in 
production at that time to provide adequate evacuation and emergency 
response time. Since that time, under Sec. Sec.  21.21(b)(2) and 
25.601, the FAA has applied issue papers to new type certification 
projects that approved applicants' proposals to reduce the risk of fuel 
tank explosions by incorporating flame arrestors with a 2 minute and 30 
second delay capability.
    The FAA also reviewed other rules related to passenger safety when 
selecting the delay of 2 minute and 30 seconds for a fuel tank vent 
protection standard. Section 25.803, ``Emergency evacuation,'' sets a 
performance-based standard that, under specified conditions, the 
airplane must be capable of being evacuated within 90 seconds. The 
conditions assume the availability of a minimum number of exits and 
that all passengers are uninjured and physically capable of departing 
the airplane. However, experience has shown that this is not always the 
case after an accident, so additional time is needed for passenger 
evacuation and emergency response.
    Section 25.856, ``Thermal/Acoustic insulation materials,'' sets 
minimum standards for preventing penetration of a fuel fire through the 
airplane fuselage, including testing requirements in appendix F of part 
25 that require 5 minutes as the minimum burn-through time.\11\ Studies 
of past accidents 12 13 show the greatest benefits in 
evacuating passengers and allowing emergency crews time to arrive are 
provided with a minimum burn-through time of 5 minutes. However, flame 
arrestors that meet a 5-minute standard would need to be significantly 
larger and heavier than a flame arrestor meeting the 2 minute and 30 
second standard. Such arrestors could also require changes to the fuel 
system vent lines in order to meet airplane refueling performance 
requirements, resulting in additional cost. Therefore, a minimum 
standard of 2 minutes and 30 seconds is appropriate for preventing the 
propagation of flames from outside the tank through the fuel tank vents 
into fuel tank vapor spaces.
---------------------------------------------------------------------------

    \11\ This time includes 1 minute for a fire to penetrate the 
fuselage skin and an additional 4 minutes for the fire to burn 
through the insulation.
    \12\ DOT/FAA/AR-99/57, ``Fuselage Burnthrough Protection for 
Increased Postcrash Occupant Survivability: Safety Benefit Analysis 
Based on Past Accidents,'' September 1999.
    \13\ DOT/FAA/AR-09/18, ``Determination of Evacuation and 
Firefighting Times Based on an Analysis of Aircraft Accident Fire 
Survivability Data,'' May 2009.

---------------------------------------------------------------------------

[[Page 41203]]

C. Summary of the NPRM

    On August 1, 2014, the FAA issued an NPRM proposing to amend 
Sec. Sec.  25.975, 121.1119, and 129.119. The Federal Register 
published that NPRM as Notice No. 14-07, Docket No. FAA-2014-0500, on 
August 15, 2014 (79 FR 48098). In that NPRM, the FAA proposed to 
require that fuel tank designs prevent fuel tank explosions, for a 
minimum of 2 minutes and 30 seconds, caused by propagation of flames 
from outside the tank through the fuel tank vents into vapor spaces 
when any vent is continuously exposed to flame.
    The comment period closed on September 29, 2014.

D. General Overview of Comments

    The FAA received 19 comments from 10 commenters representing 
airplane manufacturers, regulators, a pilots association, and 
individuals. The Air Line Pilots Association (ALPA) and three 
individuals provided general comments in support of the amendments. The 
other commenters generally supported the proposed changes; however, 
some commenters suggested changes.
    The FAA received comments on the following areas of the proposal:
     Minimum time for preventing flame propagation;
     Applicability of new Sec. Sec.  121.1119 and 129.119;
     Applicability and compliance time for newly manufactured 
airplanes; and
     Economic evaluation.

III. Discussion of the Final Rule and Public Comments

A. ``Fuel tank vents and carburetor vapor vents'' (Sec.  25.975)

    With some modification from what the FAA proposed in the NPRM, this 
final rule adds a new paragraph, (a)(7), to Sec.  25.975 to require 
fuel tank vent systems be designed to prevent the propagation of flames 
from outside the tank through the fuel tank vents into fuel tank vapor 
spaces for a period of 2 minutes and 30 seconds. The intent of this new 
requirement is to prevent or delay fuel tank explosions to allow safe 
evacuation of passengers and crew, and to allow emergency personnel 
time to reach an accident and provide assistance.
    Boeing recommended replacing the proposed minimum time requirement 
of 2 minutes and 30 seconds with 90 seconds. Boeing commented that, to 
meet the proposed requirement, current Boeing airplanes may need to be 
redesigned, and current flame arrestor installations would have to be 
redesigned and recertified, both at significant cost. Boeing also 
commented that 90 seconds would allow sufficient time to evacuate 
passengers safely and be consistent with other evacuation time limits 
in Sec.  25.803.
    When considering Boeing's comment that its designs would not meet 
the proposed 2 minute and 30 second delay, the FAA requested 
certification data for in-production Boeing designs and confirmed that 
existing Boeing flame arrestors meet the 2 minute and 30 second 
standard. Boeing's own data, from its approved flame arrestor 
installations, do not support its suggested standard of only 90 
seconds. Also, as previously discussed, research data from accidents 
used to develop the requirements in Sec.  25.856 do not support 
Boeing's position that a 90-second standard would provide adequate 
safety.
    Lockheed Martin Aeronautics Company and Embraer commented their 
currently approved flame arrestor systems may not comply with the 
standard and would necessitate redesign of the systems for new 
production airplanes.
    While the FAA determined that most \14\ of these systems would not 
require redesign, the FAA has concluded that it would not be cost-
effective to require redesign of any existing systems that do not meet 
the new standard. Therefore, we have revised the provisions of 
Sec. Sec.  121.1119 and 129.119 to prohibit operation of new production 
airplanes unless an FAA-approved means to prevent fuel tank explosions 
caused by propagation of flames from outside the fuel tanks is 
installed and operational. Both of these regulations permit the 
continued installation and operational use of previously approved means 
to prevent such fuel tank explosions. For those airplanes that do not 
currently have such approved means, the design approval holder would be 
required to show compliance with the new standard to obtain approval.
---------------------------------------------------------------------------

    \14\ The previously approved Lockheed 328 and Embraer flame 
arrestors would not have met the 2 minute and 30 second requirement.
---------------------------------------------------------------------------

    Lockheed requested a reduction of the minimum time requirement to 
120 seconds for airplanes approved for cargo-only operations due to 
shorter evacuation times needed for fewer occupants in the airplane. In 
addition, Lockheed contends that the FAA has previously accepted 
designs on cargo airplanes that did not meet the 2 minute and 30 second 
standard.
    Lockheed raised a valid point regarding the Lockheed 382 cargo 
airplanes equipped with flame arrestors. In considering this request, 
the FAA reviewed past certification data and supporting documentation 
submitted by Lockheed. Lockheed amended the design of the Lockheed 382 
to include fuel tank vent flame arrestors in 2008. At that time, there 
was no regulatory requirement for a 2 minute and 30 second capability 
for the fuel tank vent flame arrestors. Therefore, based on retrofit of 
flame arrestors into an existing design and the operation of the 
airplane for cargo use only, the FAA approved a 2-minute capability for 
the flame arrestor installation on those airplanes.
    Since 2008, however, the FAA has determined that cargo operations 
should not be a basis for a fuel vent protection regulatory 
requirement. Cargo airplanes are commonly modified and operated in 
various configurations that may allow carriage of supernumeraries and 
passengers. Providing longer fuel tank vent protection time may also 
prevent a fuel tank explosion that endangers ground support or 
emergency response personnel. Therefore, the FAA does not agree with 
Lockheed that a 2-minute standard should be adopted as the standard for 
all cargo transport airplanes, and the FAA is adopting Sec.  
25.975(a)(7) as proposed.
    Embraer requested the rule be limited to preventing fuel tank 
explosions following a crash landing. Embraer supported its request by 
inferring that Sec.  25.979, ``Pressure fueling system,'' and 
associated refueling procedures included in aircraft maintenance 
manuals address explosions during refueling and other ground operating 
conditions.
    The FAA does not agree that the regulation should only apply to 
post-crash scenarios. In addition to fuel and oil spillage following 
survivable accidents, fires outside of the airplane fuel tanks have 
been caused by fuel spilled during refueling and leaking airplane fuel 
tanks. These external fires may ignite fuel vapors that exit the fuel 
tank vents, resulting in flames traveling back through the vent lines 
into the fuel tank, causing fuel tank explosions. Therefore, this 
amendment addresses any event that could result in fire outside the 
fuel tanks, including refueling operations. Additionally, it is not 
redundant of Sec.  25.979 because that section only addresses the 
design of the fueling system, which would not address or prevent 
situations of spillage from improper fueling practices or leakage from 
malfunctioning fueling systems.
    The FAA made minor editorial changes to new paragraph (a)(7) in 
Sec.  25.975 from what was proposed in the

[[Page 41204]]

NPRM. The edits are for clarity and do not change the effect of the 
regulation.

B. Amendment to Sec. Sec.  121.1119 and 129.119, ``Fuel tank vent 
explosion protection''

    With minor modifications from what was proposed in the NPRM, the 
FAA is adding new operations rules requiring operators of certain 
transport category, turbine powered airplanes produced more than 2 
years after the effective date of this rule to have FAA-approved fuel 
tank vent fire protection means to prevent fuel tank vent explosions. 
This requirement is added to 14 CFR part 121, ``Operating Requirements: 
Domestic, Flag, and Supplemental Operations,'' and 14 CFR part 129, 
``Operations: Foreign Air Carriers and Foreign Operators of U.S.-
Registered Aircraft Engaged in Common Carriage.'' As discussed above, 
the FAA is not requiring manufacturers with currently approved flame 
arrestors to redesign their systems in order to comply with Sec. Sec.  
121.1119 and 129.119.
    This amendment applies to subject airplanes that are issued an 
original airworthiness certificate beginning 24 months after the 
effective date of this final rule. The FAA based the 24-month 
compliance period on time estimates needed to design and develop fuel 
tank vent protection means for existing airplane models that do not 
have previously approved flame arrestors. Flame arrestor technology is 
currently available. Adaptation of this technology, and the 
certification and incorporation of the design into airplanes currently 
in production should be achievable within the two-year compliance time.
    Bombardier recommended withdrawal of the proposed changes to parts 
121 and 129, citing a lack of demonstrated safety improvement and the 
added cost of flame arrestors.
    The FAA accounted for the cost to Bombardier products in the 
economic evaluation for the NPRM and found safety benefits based on 
industry recommendations and the risks documented in the ADs issued on 
certain airplane models. In addition to the 737 AD discussed in 
paragraph IIB, the FAA has issued other ADs to either require flame 
arrestors or verify their functionality on the Lockheed Model 1649A 
piston airplane,\15\ Boeing Models 707 and 720,\16\ the Beech Model 
400A,\17\ and the Lockheed Model 382.\18\ The FAA has found that there 
is a safety benefit and economic justification to include a requirement 
in this amendment to bring all newly produced airplanes that are 
subject to this rulemaking that will operate under the requirements of 
Sec.  121.1119 or Sec.  129.119 up to the level of safety established 
for the airplanes that are subject to these referenced ADs. Therefore, 
the FAA did not make any changes as a result of this comment.
---------------------------------------------------------------------------

    \15\ AD 59-20-02 LOCKHEED: Effective October 15, 1959, for items 
(1) and (2) and December 1, 1959, for item (3).
    \16\ AD 67-23-02 BOEING: Amendment 39-462. Effective September 
10, 1967.
    \17\ AD 92-16-14 BEECH: Amendment 39-8323; Docket No. 92-NM-95-
AD; effective September 1, 1992.
    \18\ AD 2011-15-02 LOCKHEED: Amendment 39-16749; Docket No. FAA-
2010-1305; effective August 19, 2011.
---------------------------------------------------------------------------

    Embraer stated that it believes that the FAA's intent is to address 
specifically those higher capacity airplanes operating in scheduled 
airline service, and to prevent operators from escaping compliance by 
reducing the passenger or payload capacity to below the specified 
limits; and it believes that the FAA's intent is not to also require 
compliance for certain business jets that happen to be on a type 
certificate. Embraer noted that these smaller airplanes do not operate 
in part 121, but there are foreign-based charter operators who operate 
airplanes leased from U.S. owners who have FAA operating certificates 
issued under Sec.  129.1(b). Embraer noted that if these operators were 
U.S. based, they would be part 135 air taxi operations that would not 
be subject to the requirements proposed in the NPRM. Therefore, Embraer 
suggested that the proposed Sec.  129.119 be revised to except the 
Bombardier CL-600-2B16 and the Embraer EMB-135BJ.
    The FAA does not concur with the request to exclude specific models 
from coverage under Sec.  129.119. As proposed, this section would 
exclude airplanes with capacities below the specified thresholds. 
However, as Embraer recognizes, the proposed Sec.  129.119(a) included 
the following qualifier: ``as a result of original type certification 
or later increase in capacity.'' The proposed Sec.  121.1119(a) 
contained this same language. Embraer correctly points out that, for 
certain Embraer and Bombardier models, this would have the unintended 
effect of applying the requirements to business jets that are included 
on the same type certificates as larger air carrier airplanes, even 
though the business jets have capacities below those specified in 
Sec. Sec.  129.119 and 121.1119. To prevent the requirement from 
applying to these smaller airplanes, the FAA has eliminated the quoted 
qualifier in both identified sections in this final rule. In the 
future, if either Embraer or Bombardier choose to amend the type 
certificates to increase the capacity of these airplanes above the 
specified thresholds, Sec. Sec.  129.119 and 121.1119 would apply to 
those newly produced airplanes.

C. Comments on the Economic Evaluation

    EASA supported the proposal but commented that the regulatory 
economic evaluation should be revised to include the ATR42 and ATR 72 
(ATR42/72). EASA noted these airplane models do not have flame 
arrestors in the fuel tank vents and would be affected by the flame 
arrestor requirement for newly manufactured airplanes entering U.S. 
service under parts 121 and 129.
    The FAA does not agree. Certification costs incurred by foreign 
manufacturers are not included in cost analyses of proposed U.S. 
regulations. Costs incurred by U.S. operators of foreign-produced 
airplanes are included in such analyses. For this final rule, however, 
the FAA estimates these costs to be minimal for newly produced ATR42/72 
airplanes, since the FAA expects the annual number of ATR42/72 
deliveries to be few, if any. The FAA has determined that there are no 
planned deliveries of ATR42/72 airplanes to U.S. airline operators 
after 2018 when the final rule will take effect. Therefore, the FAA is 
not revising the economic analysis to include the ATR42/72.
    Embraer also commented that the cost of the rule should be revised 
to include modification of an additional airplane model. One of its 
airplane models is designed to open a secondary refueling valve when 
the airplane being refueled does not have a flame arrestor. The primary 
vent outlets located near the wing tips have previously approved flame 
arrestors that meet the rule. The only affected airplane model with the 
open secondary vent design is the EMB145. Embraer currently has no 
orders or forecast deliveries for EMB145 airplanes with the unique 
secondary refueling vent.
    In addition, even if future sales of this model occur, costs 
incurred by foreign manufacturers are not included in the costs of 
compliance, as costs directly attributable to foreign entities are not 
included in the cost-benefit analysis of U.S. regulations. Therefore, 
the FAA did not change the economic evaluation in response to this 
comment.

D. Differences Between the NPRM and the Final Rule

    The FAA is adopting these rules as proposed in the NPRM with 
modifications as discussed above. Specifically, the FAA is revising 
Sec. Sec.  121.1119 and 129.119 to remove the

[[Page 41205]]

qualifying statement ``as a result of original type certification or 
later increase in capacity,'' and to require only that fuel tank vent 
system explosion prevention means for new production airplanes be FAA-
approved.

IV. Regulatory Notices and Analyses

A. Regulatory Evaluation

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Orders 12866 and 13563 direct that each 
Federal agency shall propose or adopt a regulation only upon a reasoned 
determination that the benefits of the intended regulation justify its 
costs. Second, the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) 
requires agencies to analyze the economic impact of regulatory changes 
on small entities. Third, the Trade Agreements Act (Pub. L. 96-39) 
prohibits agencies from setting standards that create unnecessary 
obstacles to the foreign commerce of the United States. In developing 
U.S. standards, the Trade Act requires agencies to consider 
international standards and, where appropriate, that they be the basis 
of U.S. standards. Fourth, the Unfunded Mandates Reform Act of 1995 
(Pub. L. 104-4) requires agencies to prepare a written assessment of 
the costs, benefits, and other effects of proposed or final rules that 
include a Federal mandate likely to result in the expenditure by State, 
local, or tribal governments, in the aggregate, or by the private 
sector, of $100 million or more annually (adjusted for inflation with 
base year of 1995). This portion of the preamble summarizes the FAA's 
analysis of the economic impacts of the final rule. The FAA suggests 
readers seeking greater detail read the full regulatory evaluation, a 
copy of which is in the docket for this rulemaking.
    In conducting these analyses, the FAA has determined that this 
final rule: (1) Has benefits that justify its costs; (2) is not an 
economically ``significant regulatory action'' as defined in section 
3(f) of Executive Order 12866; (3) is not ``significant'' as defined in 
DOT's Regulatory Policies and Procedures; (4) will not have a 
significant economic impact on a substantial number of small entities; 
(5) will not create unnecessary obstacles to the foreign commerce of 
the United States; and (6) will not impose an unfunded mandate on 
state, local, or tribal governments, or on the private sector by 
exceeding the threshold identified above. These analyses are summarized 
below.
Total Costs and Benefits of This Final Rule
    The FAA finds the final rule to be cost-beneficial because the 
costs of the rule are low enough that the benefits of preventing just 
two fatalities outweigh the expected costs ($4.9 million in present 
value benefits versus $4.4 million in present value costs). If this 
action is not taken, a hazard will continue to exist even though 
effective and low-cost means are available to minimize or eliminate it.
Who is potentially affected by this Rule?
    This rule applies to applicants for new type certificates, amended 
and supplemental type certificates involving significant product-level 
changes, and manufacturers and operators of currently certificated 
airplanes produced two or more years after the effective date of this 
rule. This rule does not require retrofit of the existing fleet.
Principal Assumptions and Sources of Information
     Discount rate is 7 percent (Office of Management & Budget, 
Circular A-94, ``Guidelines and Discount Rates for Benefit-Cost 
Analysis of Federal Programs,'' October 29, 1992, p. 8).
     Value of statistical life (VSL) begins at $9.2 million in 
2013, and increases thereafter by an annual growth factor of 1.0107. 
Memorandum: Guidance on Treatment of the Economic Value of a 
Statistical Life in Department Analyses--2014 Adjustment, June 13, 
2014. United States, Office of the Secretary of Transportation.
     For small part 25 manufacturers: An FAA study anticipates 
two U.S. airplane certifications in next 10-year period, twenty-one 
annual U.S. deliveries per U.S. certification; three foreign airplane 
certifications in next 10-year period, eleven annual U.S. deliveries 
per foreign certification, 15-year airplane production run; 30-year 
retirement age. Internal FAA study.
     Current airplane models that could be affected by 
production cut-in requirement: Bombardier Dash 8, CJ-700, and CJ-900. 
FAA 2013 Fleet Forecast, Fleet Forecast Sheet ``FAA U.S. Airlines 2013-
2013 1-18-2103,'' ``Totals & FAA Tables.''
     The period of analysis for new certifications is 45 years 
to account for a complete product life cycle determined by a 15-year 
production period and a 30-year service period.
     Certification cost estimates for part 25 airplanes--Small 
U.S. part 25 airplane manufacturers.
     Maintenance cost per airplane (every four years) for 
Bombardier CJ-700/CJ-900 regional jets (subject to production cut-in)--
$240. This estimate is much lower than the U.S. estimate because it is 
for passenger airplane models while the U.S. estimate is for business 
jet models. Since business jets are more prone to sit for extended 
periods of time, their flame arrestors can more easily be clogged by 
ice, mud daubers, or other debris, thus requiring more frequent and 
longer maintenance.
     Minimal fuel costs as flame arrestors weigh between 2 and 
4 pounds each.
Costs of This Final Rule
    The costs of the final rule are engineering, production, and 
maintenance compliance costs for newly certificated part 25 airplanes 
and for the production cut-in of part 25 airplanes used in part 121 
operations. The FAA first estimates compliance costs for new 
certifications and then for the production cut-in.
    For newly certificated airplanes, compliance costs consist of 
engineering and production costs of U.S. manufactured airplanes 
delivered to U.S. operators and maintenance costs of both U.S. and 
foreign airplanes delivered to U.S. operators. U.S. part 25 
manufacturers directly incur the engineering and production costs while 
U.S. operators directly incur the maintenance costs. Engineering and 
production costs incurred by foreign manufacturers are not included in 
the costs of compliance, as costs directly attributable to foreign 
entities are not included in the U.S. social cost and benefit analysis 
of U.S. regulations.
    To calculate the cost of new U.S. certifications, the FAA assumes 
that all new certifications will be approved one year after the 
effective date of the rule, with production beginning one year later. 
Using an airplane life cycle model, the FAA estimates the economic 
impact for two new certificates, production of 21 airplanes/
certificate/year, production runs of 15 years and an airplane 
retirement age of 30 years. Compliance costs per year are calculated 
over an airplane life cycle of 45 years.
    Cost estimates were solicited from small part 25 manufacturers 
because large airplane manufacturers (Boeing and Airbus) are already 
compliant with the final rule. These cost estimates are shown in the 
table below.

[[Page 41206]]

 Industry Cost Estimates Using Flame Arrestors To Comply With Final Rule
                                ($ 2013)
------------------------------------------------------------------------
           Cost category                 Cost               Notes
------------------------------------------------------------------------
Nonrecurring Engineering Costs....       $ 142,000  per model.
Recurring Cost (Hardware &                   3,000  per model (two flame
 Installation).                                      arrestors @$1,500
                                                     each).
Maintenance Cost (U.S.                         415  per airplane
 manufactured airplanes).                            annually.
Maintenance Cost (Bombardier                   240  per airplane every 4
 manufactured airplanes).                            years.
------------------------------------------------------------------------

    The basic cost estimates consist of nonrecurring (one-time) 
engineering costs, production costs for two flame arrestors per 
airplane (one per fuel tank) and maintenance costs per airplane per 
year. The Bombardier maintenance cost estimate is used for estimating 
production cut-in costs of compliance.
    Incorporating the industry cost estimates into the airplane life 
cycle model, the FAA finds total costs for new certification airplanes 
to be $16.2 million with present value of $4.2 million. $2.2 million of 
these costs (present value $1.2 million) are directly incurred by U.S. 
manufacturers, and $14.0 million (present value $2.1 million) are 
directly incurred by U.S. operators.\19\ For details, see the full 
regulatory evaluation in the docket.
---------------------------------------------------------------------------

    \19\ Details may not sum to totals due to rounding.
---------------------------------------------------------------------------

    In addition to the requirement applying to new certifications, the 
final rule will also require a production cut-in for currently produced 
part 25 airplanes used in part 121 operations.\20\ To calculate this 
cost, the FAA first notes that the only currently produced and U.S.-
operated airplane models not already in compliance are the Bombardier 
Dash 8 turboprops and Bombardier CRJ-700/CRJ-900 regional jets. The 
final rule will apply to these Bombardier models produced beginning in 
2018. Since the FAA forecasts no Dash 8 deliveries to U.S. airline 
operators after 2017, the FAA expects no Dash 8 compliance cost for 
those operators.
---------------------------------------------------------------------------

    \20\ We do not estimate costs for the analogous part 129 
requirement as these costs are directly incurred by foreign 
operators.
---------------------------------------------------------------------------

    The FAA does forecast the delivery of 338 CRJ-700 and 161 CRJ-900 
model airplanes to U.S. airline operators over the period 2018-2033. 
The engineering and production compliance costs for these airplanes are 
not included in our cost estimates because, as noted above, costs 
directly incurred by foreign entities are not included in the cost and 
benefit analysis of U.S. regulations. Accordingly, for these airplanes 
the FAA assesses the impact on U.S. operators only, using Bombardier's 
maintenance cost estimate of $240 every four years. Allocating this 
cost as $60 annually and assuming a production period of 16 years, the 
FAA calculates the maintenance costs for these airplanes from the first 
year of service to the retirement year of the last airplanes produced, 
using a procedure analogous to that used for new certification 
airplanes. The FAA finds these costs to operators to be $898,200 with 
present value $178,439.
    Production cut-in costs of $898,200 (present value $178,439) added 
to new certification airplane costs of $16.2 million (present value 
$4.2 million) yield total rule costs of $17.1 million (present value 
$4.4 million).
Benefits of This Final Rule
    Notwithstanding the absence of post-crash fuel tank explosions in 
recent years and lacking other sufficient bases upon which to estimate 
future risks, the merits of the final rule can be assessed by 
considering the number of fatalities that would need to be prevented to 
offset the costs of the rule.
    The FAA estimates the breakeven benefits of the rule by estimating 
the number of averted fatalities necessary to offset the $4.4 million 
present value costs of the rule. The FAA finds that just two averted 
fatalities would offset these estimated costs. For details see the full 
regulatory evaluation in the docket.

B. Regulatory Flexibility Determination

    The Regulatory Flexibility Act (RFA) of 1980 (Pub. L. 96-354) 
establishes ``as a principle of regulatory issuance that agencies shall 
endeavor, consistent with the objectives of the rule and of applicable 
statutes, to fit regulatory and informational requirements to the scale 
of the businesses, organizations, and governmental jurisdictions 
subject to regulation. To achieve this principle, agencies are required 
to solicit and consider flexible regulatory proposals and to explain 
the rationale for their actions to assure that such proposals are given 
serious consideration.'' The RFA covers a wide-range of small entities, 
including small businesses, not-for-profit organizations, and small 
governmental jurisdictions. Agencies must perform a review to determine 
whether a rule will have a significant economic impact on a substantial 
number of small entities. If the agency determines that it will, the 
agency must prepare a regulatory flexibility analysis as described in 
the RFA.
    However, if an agency determines that a rule is not expected to 
have a significant economic impact on a substantial number of small 
entities, section 605(b) of the RFA provides that the head of the 
agency may so certify and a regulatory flexibility analysis is not 
required. The certification must include a statement providing the 
factual basis for this determination, and the reasoning should be 
clear.
    All small U.S. manufacturers affected by this rule are wholly owned 
subsidiaries of large companies, who have more than 1,500 employees 
(the small business criterion for aircraft manufacturing) and, 
therefore, are not classified as small entities by the Small Business 
Administration. Part 121 operators will be directly affected by the 
average $415 annual maintenance cost per airplane. These costs are 
minimal, especially compared to the high cost of new part 25 airplanes. 
The FAA received no comments on this same finding in the NPRM.
    If an agency determines that a rulemaking will not result in a 
significant economic impact on a substantial number of small entities, 
the head of the agency may so certify under section 605(b) of the RFA. 
Therefore, as provided in section 605(b), the head of the FAA certifies 
that this rulemaking will not result in a significant economic impact 
on a substantial number of small entities.

C. International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the 
Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal 
agencies from establishing standards or engaging in related activities 
that create unnecessary obstacles to the foreign commerce of the United 
States. Pursuant to these Acts, the establishment of standards is not 
considered an unnecessary obstacle to the foreign commerce of the 
United States, so long as the standard has a legitimate domestic 
objective, such as the protection of safety, and does not operate in a 
manner that excludes imports that meet this objective. The

[[Page 41207]]

statute also requires consideration of international standards and, 
where appropriate, that they be the basis for U.S. standards.
    The FAA has assessed the effect of this final rule and determined 
that its purpose is to ensure the safety of U.S. civil aviation. 
Therefore, the rule is in compliance with the Trade Agreements Act.

D. Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare a written statement 
assessing the effects of any Federal mandate in a proposed or final 
agency rule that may result in an expenditure of $100 million or more 
(in 1995 dollars) in any one year by State, local, and tribal 
governments, in the aggregate, or by the private sector; such a mandate 
is deemed to be a ``significant regulatory action.'' The FAA currently 
uses an inflation-adjusted value of $155.0 million in lieu of $100 
million. This final rule does not contain such a mandate; therefore, 
the requirements of Title II of the Act do not apply.

E. Paperwork Reduction Act

    The Paperwork Reduction Act of 1995 (44 U.S.C. 3507(d)) requires 
that the FAA consider the impact of paperwork and other information 
collection burdens imposed on the public. The FAA has determined that 
there is no new requirement for information collection associated with 
this final rule.

F. International Compatibility and Cooperation

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, it is FAA policy to conform to 
International Civil Aviation Organization (ICAO) Standards and 
Recommended Practices to the maximum extent practicable. The FAA has 
determined that there are no ICAO Standards and Recommended Practices 
that correspond to these proposed regulations.

G. Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically 
excluded from preparation of an environmental assessment or 
environmental impact statement under the National Environmental Policy 
Act in the absence of extraordinary circumstances. The FAA has 
determined this rulemaking action qualifies for the categorical 
exclusion identified in paragraph 312f and involves no extraordinary 
circumstances.

V. Executive Order Determinations

A. Executive Order 13132, Federalism

    The FAA has analyzed this final rule under the principles and 
criteria of Executive Order 13132, Federalism. The agency determined 
that this action will not have a substantial direct effect on the 
States, or the relationship between the Federal Government and the 
States, or on the distribution of power and responsibilities among the 
various levels of government, and, therefore, does not have Federalism 
implications.

B. Executive Order 13211, Regulations That Significantly Affect Energy 
Supply, Distribution, or Use

    The FAA analyzed this final rule under Executive Order 13211, 
Actions Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). The agency has determined that it 
is not a ``significant energy action'' under the executive order, and 
it is not likely to have a significant adverse effect on the supply, 
distribution, or use of energy.

VI. How To Obtain Additional Information

A. Rulemaking Documents

    An electronic copy of a rulemaking document may be obtained by 
using the Internet--
    1. Search the Federal eRulemaking Portal (http://www.regulations.gov);
    2. Visit the FAA's Regulations and Policies Web page at http://www.faa.gov/regulations_policies/ or
    3. Access the Government Printing Office's Web page at http://www.gpo.gov/fdsys/.
    Copies may also be obtained by sending a request (identified by 
notice, amendment, or docket number of this rulemaking) to the Federal 
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence 
Avenue SW., Washington, DC 20591, or by calling (202) 267-9680.

B. Comments Submitted to the Docket

    Comments received may be viewed by going to http://www.regulations.gov and following the online instructions to search the 
docket number for this action. Anyone is able to search the electronic 
form of all comments received into any of the FAA's dockets by the name 
of the individual submitting the comment (or signing the comment, if 
submitted on behalf of an association, business, labor union, etc.).

C. Small Business Regulatory Enforcement Fairness Act

    The Small Business Regulatory Enforcement Fairness Act (SBREFA) of 
1996 requires the FAA to comply with small entity requests for 
information or advice about compliance with statutes and regulations 
within its jurisdiction. A small entity with questions regarding this 
document, may contact its local FAA official, or the person listed 
under the FOR FURTHER INFORMATION CONTACT heading at the beginning of 
the preamble. To find out more about SBREFA on the Internet, visit 
http://www.faa.gov/regulations_policies/rulemaking/sbre_act/.

List of Subjects

14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

14 CFR Part 121

    Air carriers, Aircraft, Aviation safety, Reporting and 
recordkeeping requirements.

14 CFR Part 129

    Air carriers, Aircraft, Aviation safety, Reporting and 
recordkeeping requirements.

The Amendment

    In consideration of the foregoing, the Federal Aviation 
Administration amends parts 25, 121, and 129 of title 14, Code of 
Federal Regulations as follows:

PART 25--AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

0
1. The authority citation for part 25 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701, 44702 and 44704.

0
2. Amend Sec.  25.975 by revising paragraphs (a)(5) and (6) and adding 
paragraph (a)(7) to read as follows:

Sec.  25.975  Fuel tank vents and carburetor vapor vents.

    (a) * * *
    (5) There may be no point in any vent line where moisture can 
accumulate with the airplane in the ground attitude or the level flight 
attitude, unless drainage is provided;
    (6) No vent or drainage provision may end at any point--
    (i) Where the discharge of fuel from the vent outlet would 
constitute a fire hazard; or
    (ii) From which fumes could enter personnel compartments; and
    (7) Each fuel tank vent system must prevent explosions, for a 
minimum of 2 minutes and 30 seconds, caused by propagation of flames 
from outside the tank through the fuel tank vents into fuel tank vapor 
spaces when any fuel

[[Page 41208]]

tank vent is continuously exposed to flame.
* * * * *

PART 121--OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL 
OPERATIONS

0
3. The authority citation for part 121 continues to read as follows:

    Authority:  49 U.S.C. 106(f), 106(g), 40103, 40113, 40119, 
41706, 42301 preceding note added by Pub. L. 112-95, sec. 412, 126 
Stat. 89, 44101, 44701-44702, 44705, 44709-44711, 44713, 44716-
44717, 44722, 44729, 44732; 46105; Pub. L. 111-216, 124 Stat. 2348 
(49 U.S.C. 44701 note); Pub. L. 112-95, 126 Stat 62 (49 U.S.C. 44732 
note).

0
4. Add Sec.  121.1119 to subpart AA to read as follows:

Sec.  121.1119  Fuel tank vent explosion protection.

    (a) Applicability. This section applies to transport category, 
turbine-powered airplanes with a type certificate issued after January 
1, 1958, that have:
    (1) A maximum type-certificated passenger capacity of 30 or more; 
or
    (2) A maximum payload capacity of 7,500 pounds or more.
    (b) New production airplanes. No certificate holder may operate an 
airplane for which the State of Manufacture issued the original 
certificate of airworthiness or export airworthiness approval after 
August 23, 2018 unless means, approved by the Administrator, to prevent 
fuel tank explosions caused by propagation of flames from outside the 
fuel tank vents into the fuel tank vapor spaces are installed and 
operational.

PART 129--OPERATIONS: FOREIGN AIR CARRIERS AND FOREIGN OPERATORS OF 
U.S.-REGISTERED AIRCRAFT ENGAGED IN COMMON CARRIAGE

0
5. The authority citation for part 129 continues to read as follows:

    Authority:  49 U.S.C. 1372, 40113, 40119, 44101, 44701-44702, 
44705, 44709-44711, 44713, 44716-44717, 44722, 44901-44904, 44906, 
44912, 46105, Pub. L. 107-71 sec. 104.

0
6. Add Sec.  129.119 to subpart B to read as follows:

Sec.  129.119  Fuel tank vent explosion protection.

    (a) Applicability. This section applies to transport category, 
turbine-powered airplanes with a type certificate issued after January 
1, 1958, that have:
    (1) A maximum type-certificated passenger capacity of 30 or more; 
or
    (2) A maximum payload capacity of 7,500 pounds or more.
    (b) New production airplanes. No certificate holder may operate an 
airplane for which the State of Manufacture issued the original 
certificate of airworthiness or export airworthiness approval after 
August 23, 2018 unless means, approved by the Administrator, to prevent 
fuel tank explosions caused by propagation of flames from outside the 
fuel tank vents into the fuel tank vapor spaces are installed and 
operational.

    Issued under authority provided by 49 U.S.C. 106(f) and 44701(a) 
in Washington, DC, on June 7, 2016.
Michael P. Huerta,
Administrator.
[FR Doc. 2016-14454 Filed 6-23-16; 8:45 am]
 BILLING CODE 4910-13-P
```