[Federal Register Volume 83, Number 130 (Friday, July 6, 2018)]
[Proposed Rules]
[Pages 31479-31488]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-14270]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 33
[Docket No. FAA-2018-0568; Notice No. 18-02]
RIN 2120-AK83
Medium Flocking Bird Test at Climb Condition
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes the addition of a new test requirement to the
airworthiness regulation addressing engine bird ingestion. The current
regulation ensures bird ingestion capability of the turbofan engine fan
blades, but the existing test conditions do not adequately demonstrate
bird ingestion capability of the engine core. This proposed rule would
require that, to obtain certification of a turbofan engine, a
manufacturer must show that the engine core can continue to operate
after ingesting a medium sized bird while operating at a lower fan
speed associated with climb or landing. This new requirement would
ensure that engines can ingest the largest medium flocking bird
required by the existing
[[Page 31480]]
rule into the engine core at climb or descent conditions.
DATES: Send comments on or before September 4, 2018.
ADDRESSES: Send comments identified by docket number FAA-2018-0568
using any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments
from the public to better inform its rulemaking process. DOT posts
these comments, without edit, including any personal information the
commenter provides, to www.regulations.gov, as described in the system
of records notice (DOT/ALL-14 FDMS), which can be reviewed at
www.dot.gov/privacy.
Docket: Background documents or comments received may be read at
http://www.regulations.gov at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Alan Strom, Federal Aviation
Administration, Engine and Propeller Standards Branch, Aircraft
Certification Service, AIR-6A1, 1200 District Avenue, Burlington,
Massachusetts 01803-5213; telephone (781) 238-7143; fax (781) 238-7199;
email [email protected].
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 issued under the authority described in 49
U.S.C. 44701(a)(1). Under that section, the FAA is charged with, among
other things, prescribing minimum safety standards for aircraft engines
used in the flight of civil aircraft in air commerce. This proposed
rule is within the scope of that authority because it updates existing
regulations for certification of aircraft turbofan engines.
I. Overview of Proposed Rule
This proposed rule would create an additional bird ingestion test
for turbofan engines. The new requirements would be added to 14 CFR
33.76, which covers engine testing for bird ingestion. This new test
would ensure that engines can ingest the largest medium flocking bird
(MFB) required by the existing rule, into the engine core at climb
conditions. If the engine design is such that no bird material will be
ingested into the engine core \1\ during the test at climb conditions,
then the proposed rule would require a different test at approach
conditions.
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\1\ Turbofan engines have fan and core rotors. The fan or low
pressure compressor is at the front of the engine. The core consists
of additional compressor stages behind the fan.
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The proposed test consists of firing at the engine core one MFB,
equivalent to the largest bird currently required by Sec. 33.76(c) for
the engine inlet throat area of the engine being tested, using either
the following climb or descent testing conditions for an engine:
(1) Testing for bird ingestion on climb. The test bird would be
fired at 250-knots, with the mechanical engine fan speed set at the
lowest expected speed when climbing through 3,000 feet altitude above
ground level (AGL). After bird ingestion, the proposal would require
that the engine comply with post-test run-on requirements similar to
those in existing Sec. 33.76(d)(5), large flocking bird (LFB) test,
except that, depending on the climb thrust of the engine, less than 50
percent takeoff thrust may be allowed during the first minute after
bird ingestion.
(2) Testing for bird ingestion on descent. If the applicant
determines that no bird mass will enter the core during the test at the
250-knots/climb condition, then the applicant would be required to
perform an alternative test to that described in the paragraph (1). For
this test, the bird would be fired at 200-knots, with the engine
mechanical fan speed set at the lowest fan speed expected when
descending through 3,000 feet altitude AGL on approach to landing.
Applicants would be required to comply with post-test run-on
requirements that are the same as the final six (6) minutes of the
existing Sec. 33.76(d)(5) post-test run-on requirements for large
flocking birds (LFB). This is based on the assumption that the airplane
will already be lined up with the runway.
Summary of Costs and Benefits
The FAA estimates the annualized costs of this proposed rule to be
$4 million, or $52 million over 27 years (at a seven percent present
discount rate).\2\ The FAA estimates the annualized benefits of $5
million, or $61 million over 27 years. The following table summarizes
the benefits and costs of this proposed rule.
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\2\ The FAA uses a 27-year period of analysis since it
represents one complete cycle of actions affected by the proposed
rule. One life cycle extends through the time required for
certification, production of the engines, engine installation,
active aircraft service, and retirement of the engines.
Summary of Benefits and Costs
[$Millions] *
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27-year total present value Annualized
Impact ---------------------------------------------------------------
7% 3% 7% 3%
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Benefits........................................ $61.0 $100.6 $5.1 $5.5
Costs........................................... 51.5 71.5 4.3 3.9
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Net Benefits................................ 9.4 29.1 0.8 1.6
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*Estimates may not total due to rounding. FAA uses discount rates of seven and three percent based on OMB
guidance.
[[Page 31481]]
II. Background
A. Statement of the Problem
On January 15, 2009, US Airways Flight 1549 (``Flight 1549'') took
off from La Guardia Airport in New York City. On climb, at
approximately 2,800 feet above ground level (AGL) and approximately
230-knots indicated airspeed, the airplane struck a flock of migratory
Canadian geese. Both engines ingested at least two birds. Both engine
cores suffered major damage and total thrust loss.
Flight 1549 was an Airbus Model A320 airplane. The A320 ``family''
of airplanes (i.e., Model A318/A319/A320/A321) and the Boeing Model 737
airplanes are among the most frequently used airplanes, transporting a
significant number of airline passengers around the world. Most
transport airplanes and many business aircraft use turbofan engines
that are susceptible to bird ingestion damage which, in some instances,
has resulted in greater than 50 percent takeoff thrust loss. In twin-
engine airplanes, this amount of thrust loss in both engines can
prevent the airplane to climb over obstacles or maintain altitude. This
is an unsafe condition because it can prevent continued safe flight and
landing.
As a result of the Flight 1549 accident, the FAA began studying how
to improve engine durability with respect to core engine bird
ingestion.\3\ As a result of this tasking, the Aviation Rulemaking
Advisory Committee (ARAC) working group produced a report titled,
``Turbofan Bird Ingestion Regulation Engine Harmonization Working Group
Report'', dated February 19, 2015.\4\ The ARAC working group report
concluded that modern fan blades (such as those on the Flight 1549
airplane engines) have relatively wider fan blade chords (width) than
those in service when the current MFB ingestion test (codified in 14
CFR 33.76(c)) was developed and adopted. The ARAC working group report
also pointed out that the current MFB ingestion test is conducted with
the engine operating at 100 percent takeoff power or thrust. This
setting is ideal for testing the fan blades but does not represent the
lower fan speeds used during the climb and descent phases of aircraft
flight.
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\3\ The FAA used prior studies to begin the review, such as
flocking bird ingestion reports developed as Phase I and II reports
for the current rule. The Phase III report, entitled, ``Aerospace
Industries Association Bird Ingestion Working Group Interim Report--
January 2012'' was produced after the Flight 1549 event. The Phase
III report is the most germane to this proposed rule, as it contains
the latest bird ingestion data available through January 2009,
including the Flight 1549 accident.
\4\ The FAA accepted this report on March 19, 2015. The ARAC
working group report included recommendations consistent with this
proposed rule. The FAA will file in the docket copies of the
referenced reports for this proposed rule.
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When an engine ingests a bird, the amount of bird mass that enters
the engine core depends on: (1) The width of the fan blade chord, (2)
the airplane's speed, and (3) the rotational speed of the fan blades.
The wider the chord of the fan blade and the lower the speed of the
airplane, the longer the bird will remain in contact with the fan
blade. As airplane speed increases, the bird spends less time on the
fan blade. With higher fan speed, the bird will move radially faster
away from the core. Thus, the longer the time in contact with the fan
blade, from wider blades and lower airspeed, and increased centrifugal
forces from a higher fan speed result in the bird being moved further
outboard and away from the core. That makes it less likely that bird
material will enter the core during the current test compared to the
proposed test. Conversely, a lower fan speed and higher airspeed, for a
given fan blade width, makes it more likely that the bird material will
enter the core.
Currently, the MFB test is conducted using 100 percent power or
thrust and 200 knots airspeed, simulating takeoff conditions.
Consequently, the current MFB test does not simulate lower fan speed
phases of flight (such as climb and descent) during which a bird, if
ingested, is more likely to enter the engine core. In addition, the
higher airspeed in climb is not covered by the existing test.
Therefore, the existing small and medium flocking bird test prescribed
in Sec. 33.76(c) do not provide the intended demonstration of core
durability against bird ingestion for climb and descent conditions.
B. Related Actions
Before proposing this rule, the FAA reviewed other actions taken by
this agency to reduce threats of engine bird ingestion and concluded
that these actions would not mitigate the specific risk discussed
above. These actions include the following:
(1) Advisory Circular (AC) 150/5200-33B, ``Hazardous Wildlife
Attractants on or Near Airports'' provides guidance on certain land
uses that have the potential to attract hazardous wildlife on or near
public-use airports.
(2) AC 150/5200-34A, ``Construction or Establishment of Landfills
Near Public Airports'' provides guidance to minimize the impact to air
safety when landfills, that often attract birds, are established near
public airports.
(3) 14 CFR 139.337, Wildlife hazard management, identifies
certified Airport Operator responsibilities with respect to hazardous
wildlife issues.
(4) FAA Airport Safety website, Wildlife Strike Resources,
available at http://www.faa.gov/airports/airport_safety/wildlife/resources/, provides information on wildlife strike prevention,
database links, and bird strike/ingestion report forms, for use by
airport authorities, airlines, industry, and the public.
Most bird ingestions occur within five miles of an airport, and the
ACs discussed above generally only apply within that radius. However,
the Flight 1549 accident occurred more than five miles from La Guardia
Airport, and the ingested birds were migratory. Therefore, while
airport bird mitigation efforts are necessary to reduce engine bird
ingestion incidents, these efforts will neither eliminate all flocking
bird encounters, nor reduce the chance that such encounters could
affect more than one engine on an airplane.
C. National Transportation Safety Board (NTSB) Recommendations
The National Transportation Safety Board (NTSB) has issued two
engine-related safety recommendations to the FAA:
(1) A-10-64: Modify the small and medium flocking bird
certification test standard to require that the test be conducted using
the lowest expected fan speed, instead of 100 percent fan speed, for
the minimum climb rate.
(2) A-10-65: During re-evaluation of the current engine bird-
ingestion certification regulations by the Bird Ingestion Rulemaking
Database working group, specifically re-evaluate the LFB certification
test standards to determine if they should:
(a) Apply to engines with an inlet area of less than 2.5 square
meters (3,875 square inches).
(b) Include an engine core ingestion requirement.
If re-evaluation determines the need for these requirements,
incorporate them into 14 CFR 33.76(d) and require that newly
certificated engines be designed and tested to these requirements.
The ARAC working group addressed both NTSB safety recommendations.
In response to NTSB safety recommendation A-10-64, the ARAC working
group recommended the test in this proposed rule. The ARAC working
group found that its recommendation would also address the intent of
NTSB safety recommendation A-10-65, since the kinetic energy of the
bird in the proposed rule is of the same magnitude as a LFB test.
[[Page 31482]]
III. Discussion of the Proposal
A. Hazard Identification
There are two types of engine bird ingestion hazards related to
turbofan-powered aircraft: Single- and multiple-engine bird ingestion.
This proposed rule addresses the multiple-engine bird ingestion hazard,
which can happen concurrently or sequentially, during the same flight.
Multiple-engine bird ingestion occurs when the airplane flies
through a bird flock that spans the distance between the engines. This
can cause engine damage that prevents thrust production, which can then
force an off-airport landing. The ARAC working group found that the
existing rules and controls are not sufficient to address the threat
from multi-engine core ingestion events.\5\
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\5\ The existing controls to prevent these hazards include
airport mitigation strategies (previously mentioned), and regulatory
controls that include 14 CFR: (a) Part 25 installation requirements,
concerning uncontained engine debris (e.g., Sec. 25.903(d)(1)) and
minimizing hazards to the airplane from foreseeable engine
malfunctions (such as Sec. Sec. 25.901(c) and 25.1309); (b) Section
33.76 certification test requirements; and (c) Part 33 requirements
(such as Sec. Sec. 33.19 and 33.94 containment requirements, Sec.
33.17 fire protection requirements, etc.).
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B. Safety Risk Analysis
The ARAC working group conducted a risk analysis to evaluate the
bird ingestion threat using criteria that included (a) bird size class,
(b) engine inlet size class, (c) phase of flight, and (d) recorded
events with evidence of engine core flow path bird ingestion. The
analysis included (a) the overall bird ingestion rate per flight, (b)
rate of multi-engine ingestions per flight, (c) rate of power loss
resulting in available power below 50 percent of takeoff per flight,
and (d) the percent of events during each flight phase. Results from
these analyses were used to determine:
(1) If the civil air transport fleet is currently meeting its
safety goal.
(2) If engines in certain inlet size groups are performing worse
than others.
(3) If evidence of engine core ingestion indicates a greater chance
of engine power loss (post-event power available less than 50 percent
of takeoff thrust).
(4) Which flight phase poses the highest threat to engines designed
under existing regulations.
The ARAC working group also analyzed the bird ingestion threat from
(a) engine damage, and (b) engine failure to produce thrust due to
stall, surge, etc. Thrust loss from bird damage generally refers to
damage or failure of engine internal static and rotating parts. Damage
that causes any of these hazards and those listed in Sec. 33.75
(except complete inability to shut down the engine), would result in
the pilot reducing thrust to idle, or shutting down the engine.
Therefore, damage that causes any of the hazards listed in Sec.
33.75(g)(2) \6\ was considered to have the same effect as internal
damage to static and rotating engine parts.
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\6\ The hazards are: (1) Non-containment of high-energy debris;
(2) concentration of toxic products in the engine bleed air intended
for the cabin sufficient to incapacitate crew or passengers; (3)
significant thrust in the opposite direction to that commanded by
the pilot; (4) uncontrolled fire; (5) failure of the engine mount
system leading to inadvertent engine separation; (6) release of the
propeller by the engine, if applicable; and (7) complete inability
to shut the engine down.
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The ARAC working group considered two engine performance conditions
after bird ingestion, namely, less than 50 percent and more than 50
percent takeoff thrust available. Less than 50 percent takeoff thrust
available is a hazard, since it could prevent the airplane from
climbing at a safe rate to avoid obstacles, or maintain altitude. More
than 50 percent takeoff thrust available was not considered a hazard,
as the airplane could still climb at a safe rate to avoid obstacles, or
maintain altitude. Based on bird ingestion data from the Phase I
through Phase III reports, the ARAC working group found it is extremely
improbable that an airplane with more than two engines would have power
loss greater than 50 percent of takeoff thrust on three or more
engines.
Since a surge or stall could occur upon bird ingestion, the ARAC
working group assessed whether engine surge or stall, without
significant physical damage to the engine's rotating parts, would
prevent continued safe flight and landing. Based on its review of in-
service incidents, the ARAC working group determined that surge and
stall are transitory events unlikely to cause an accident, since engine
power can be recovered when the ingested material is cleared.
Modern fan blades have relatively wider fan blade chords than those
in service when the small and medium flocking bird core test in Sec.
33.76(c) was developed. At takeoff, the fan speed is higher and the
airspeed is lower than during climb. Therefore, the existing MFB core
test of Sec. 33.76(c), does not provide the intended demonstration of
core durability against bird ingestion for climb and descent
conditions. In contrast to other phases of flight, takeoff conditions
(which are simulated under the current MFB test) are more likely to
move bird material away from the core section and into the fan flow
path than climb and descent conditions (which are not simulated under
the current MFB test). Testing the engine at the bird speed and fan
speed representative of the airplane climb condition is more likely to
result in significant bird material entering the engine core during the
engine test. If the engine is designed so that no bird material enters
the core during climb, then a test at the bird speed and fan speed
associated with approach (lower bird speed but significantly lower fan
speed) is another way to ensure significant bird material enters the
core.
The FAA agrees with the ARAC working group conclusion that, for
modern engine designs, the existing Sec. 33.76(c) small and medium
flocking bird test does not demonstrate engine core flow robustness
against bird ingestion as intended.
C. Alternatives
The ARAC working group determined there were six (6) MFB test
options, as follows:
(1) Conduct the existing test; then add a new and separate core
test using a single bird at climb conditions.
(2) Conduct the existing test, but leave out the core bird test
described in Sec. 33.76(c)(2),\7\ add a new and separate core test
using a single bird at climb conditions.
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\7\ The MFB test defined in Sec. 33.76(c)(2) requires that
largest of the birds fired at the engine must be aimed at the engine
core primary flow path.
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(3) Conduct the existing test without the existing core bird test;
change the engine and bird speed conditions to match airplane climb
conditions, and then fire the final bird.
(4) Conduct the existing test using the existing core bird test;
change the engine and bird speed conditions to match airplane climb
conditions, and then fire the final bird.
(5) Combine a new MFB engine core bird test with the existing LFB
test. Fire an additional, MFB at the engine core, at least one minute
after the LFB, but before the run-on portion of the test (for
reference, the LFB is fired at 50 percent blade radius or higher, well
outside the core).
(6) Make no changes to the existing MFB regulation.
The ARAC working group concluded that a modified Option 1 is
necessary. The working group rejected options that would have
eliminated the current core bird testing requirements set forth in
Sec. 33.76(c)(2) once the new test is in place. The working group
determined that the current requirements are still needed to test the
ability of the engine
[[Page 31483]]
fan blades to withstand impact with a bird at the higher speeds present
during takeoff. Because the new test proposed in this rule uses lower
fan speed and higher bird speed than those specified in the current
core bird testing requirements, it would be able to measure the ability
of the engine core to withstand impact of bird mass that passes through
the engine fan blades during the climb and descent phases of flight.
However, the new test would not ascertain whether the engine fan blades
could safely withstand a higher-kinetic-energy impact with a bird
during the takeoff phase of flight while operating at 100 percent
takeoff power or thrust (which is measured by the current testing).
The FAA notes, however, that some aircraft are designed to operate
such that their engine power during takeoff is nearly identical to
their engine power during the climb and descent phases of flight.
Because the takeoff and post-takeoff conditions for this group of
engines are so similar, requiring an additional test that mimics post-
takeoff conditions would be needlessly repetitive for these engines, as
the current testing already measures bird ingestion during takeoff
conditions. Accordingly, this proposed rule would allow the new test to
be combined with the existing test, if the climb fan rotor speed of the
engine being tested is within 1 percent of the first fan stage rotor
speed at 100 percent takeoff thrust or power.
The new test would ensure that the core flow path of future engines
remains sufficiently robust to maintain the civil fleet catastrophic
hazard rate objective from bird ingestion. The ARAC working group chose
this option since the other options did not address the safety risk,
because they introduce unnecessary program test risk with no additional
safety benefit.
Because the Flight 1549 accident involved the ingestion of two
birds into each engine, the FAA also considered requiring that, as part
of the new test proposed in this rule, an engine must be capable of
sustaining an ingestion of two MFBs into the engine core. However, the
FAA rejected this approach as needlessly burdensome, because the
simultaneous ingestion of two MFBs into the cores of multiple engines
is an extremely rare event.
D. New Bird Ingestion Test
Under this proposed rule, Sec. 33.76 would be amended to require
turbofan engine manufacturers to demonstrate compliance with an
additional bird ingestion test. The new test would require firing the
largest MFB required by Sec. 33.76 (Table 2) at the engine core, at
one of the following two conditions:
The first test condition is at a speed of 250-knots, with the
engine fan set at the speed associated with the lowest expected climb
setting for the engine while the airplane is climbing through 3,000
feet above ground level. The post-test run-on requirements would remain
the same as the existing Sec. 33.76(d)(5). Because the climb setting
may be significantly less than takeoff thrust, less than 50 percent
takeoff thrust would be allowed up to one minute after bird ingestion.
After one minute, the engine would be required to demonstrate at least
50 percent takeoff thrust. The FAA notes that current MFB testing,
which simulates takeoff conditions, does not allow a reduction below 50
percent takeoff thrust. If this condition is present for only one
minute during one of the post-takeoff phases of flight, it would not
result in an unsafe condition because a pilot would have more time to
respond to this issue without hazard. Requiring the engine to operate
satisfactorily for one minute without throttle movement will ensure
that the engine will not stall or shut down in the time it takes the
pilot to understand that the engine has ingested a bird.
The proposed requirements of the first condition above are intended
to simulate the worst threat to the engine core in expected operating
conditions. The maximum airspeed allowed below 10,000 feet is 250-knots
indicated airspeed. Higher airspeed corresponds to less time for a bird
to be in contact with the fan blades, reducing the likelihood that the
bird would be centrifuged (moved radially outward) away from the core.
Thus a test where the bird is fired at a higher speed is more likely to
result in the bird going into the core as intended. The altitude, 3,000
feet AGL, was chosen for two reasons: (1) 91 percent of bird ingestion
events occur at or below 3,000 feet AGL and (2) during typical takeoff
and climb profiles, engine speeds are increased and the aircraft climbs
quickly after reaching 3,000 feet AGL. The post-test run-on
requirements for the climb point would be the same as the existing LFB
test (Sec. 33.76(d)(5)). The LFB post-test run-on requirements were
chosen because the major threat to the engine core happens away from
the airport when the airplane is well above the ground.
The second test condition, should the applicant determine that no
bird mass will enter the core during the test at the climb condition,
must be successfully conducted at a speed of 200-knots indicated
airspeed, with the engine fan set at the lowest expected mechanical fan
speed while the airplane is descending through 3,000 feet AGL on
approach to landing. The post-test run-on requirements would consist of
the final seven minutes of the existing LFB 20-minute post-ingestion
run-on requirement (Sec. 33.76(d)(5)) based on the assumption that the
airplane would already be lined up with the runway during this phase of
descent.
The conditions for the approach test point are based on a typical
aircraft approach profile. The post-test run-on requirements for the
approach test point were selected based on the airplane approach being
lined up with the runway and ready for landing. In addition, the
possibility of having a multi-engine power loss (more than 50 percent
loss per engine) on approach, combined with another simultaneous event
that could prevent a safe landing, is considered extremely improbable.
Finally, the approach test point would be run only if the engine has
been designed to centrifuge all bird material away from the core of the
engine during the takeoff and climb phases of flight. This test point
would reduce the total risk of power loss from engine core bird
ingestion.
Additional bird ingestion testing at the 200-knot approach
condition would ensure that, if the engine is designed to centrifuge
all bird material away from the core flow path at takeoff and climb
conditions (which is beneficial), then engine core capability to ingest
bird material would still be tested. This is because an engine that
centrifuges bird material away from the core at the 250-knot climb
condition may not be able to centrifuge away the same amount of bird
material at the lower (200-knot) speed approach condition.
The FAA notes that this proposed rule may result in the engine
manufacturer having to run an additional bird ingestion test. If the
manufacturer discovers during the 250-knot climb test that no bird
material enters the engine core, then it is required to run the 200-
knot approach test. However, the FAA anticipates the two-test scenario
is unlikely, because manufacturers would evaluate the design of its
engine prior to engine bird ingestion testing. Thus, a manufacturer
would be able to determine, prior to commencing certification testing,
whether their engine will centrifuge all bird material away from the
core. Based on this determination, the manufacturer would select the
appropriate bird ingestion test (either the 250-knot climb or 200-knot
approach test) proposed in this rule.
The European Aviation Safety Agency (EASA) has notified the FAA
that it
[[Page 31484]]
intends to incorporate requirements similar to those proposed here into
its engine bird ingestion rule, CS-E 800. Incorporating the proposed
test conditions into Sec. 33.76 would harmonize FAA requirements with
EASA requirements and ensure that applicants would only need to comply
with one set of regulations. Furthermore, incorporating these changes
would prevent confusion within the FAA and EASA when validating engines
developed under each other's regulations.
With respect to the NTSB's recommendation to apply the LFB
requirement to engines with inlet areas less than 2.5 square meters
(3,875 square inches), the evidence from the Flight 1549 accident did
not indicate a deficiency in current bird ingestion requirements for
the fan blades. The Phase II report supports the FAA's conclusion that
for engines with inlets of less than 2.5 square meters (3,875 square
inches), a LFB test requirement is not necessary to meet the safety
objective of preventing catastrophic effects from fan blade failure,
for engines of that size.
The FAA also considered whether to increase the required size of
the bird aimed at the core during the MFB test as recommended by the
NTSB. The FAA evaluated the relative effects of ingesting a MFB at the
new proposed climb condition, against a LFB at the take-off condition
in the current regulation (Sec. 33.76(d)). The LFB condition resulted
in a smaller mass fraction of the bird entering the core (0.39 versus
0.52 at the MFB condition). However, in terms of mass, a LFB fired into
the core resulted in a 20 percent higher total mass into the core than
the MFB. The FAA determined that the difference in impact energy
delivered to the core inlet was insignificant between the LFB and MFB
ingestion conditions (2 percent). This is a result of the
slower aircraft and engine fan rotor speed associated with the LFB
ingestion criteria. For this reason, this proposed rule would not
change the current LFB requirement (Sec. 33.76(d)).
IV. Regulatory Notices and Analyses
A. Regulatory Evaluation
Changes to Federal regulations must undergo several economic
analyses. First, Executive Order 12866 and Executive Order 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, this 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; current value is $155 million). This portion of the
preamble summarizes the FAA's analysis of the economic impacts of this
proposed rule. The FAA suggest readers seeking greater detail read the
full regulatory evaluation, a copy of which the FAA placed in the
docket for this rulemaking.
In conducting these analyses, the FAA has determined that this
proposed 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 ``non-significant'' as defined in
DOT's Regulatory Policies and Procedures; (4) would not have a
significant economic impact on a substantial number of small entities;
(5) would not create unnecessary obstacles to the foreign commerce of
the United States; and (6) would 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.
I. Total Benefits and Costs of This Rule
The FAA proposes the addition of a new test requirement to the
engine bird ingestion airworthiness regulation. This new requirement
would ensure that engines can ingest the medium flocking birds into the
engine core at climb conditions. The ingestion of small and medium size
birds can cause thrust loss from core engine bird ingestion if enough
bird mass enters the engine core, which in turn can cause accidents or
costly flight diversions. This proposed rule would add to the
certification requirements of turbine engines a requirement that
manufacturers must show that their engine cores can continue to operate
after ingesting a medium sized bird while operating at a lower fan
speed associated with climb out or landing. Engine manufacturers have
the capability of producing such engines.
The FAA estimates the annualized cost of the proposed rule to be $4
million, or $52 million over 27 years (discounted at 7%).\8\ The FAA
estimates annualized benefits of $5 million, or $61 million over 27
years. The following table summarizes the benefits and costs of this
proposed rule.
---------------------------------------------------------------------------
\8\ The FAA uses a 27-year period of analysis since it
represents one complete cycle of actions affected by the proposed
rule. One life cycle extends through the time required for
certification, production of the engines, engine installation,
active aircraft service, and retirement of the engines.
Summary of Benefits and Costs
[$Millions] *
----------------------------------------------------------------------------------------------------------------
27-Year total present value Annualized
Impact ---------------------------------------------------------------
7% 3% 7% 3%
----------------------------------------------------------------------------------------------------------------
Benefits........................................ $61.0 $100.6 $5.1 $5.5
Costs........................................... 51.5 71.5 4.3 3.9
---------------------------------------------------------------
Net Benefits................................ 9.4 29.1 0.8 1.6
----------------------------------------------------------------------------------------------------------------
* Estimates may not total due to rounding. The FAA uses discount rates of seven and three percent based on OMB
guidance.
[[Page 31485]]
Furthermore, this proposed rule would address two engine-related
safety recommendations that the National Transportation Safety Board
(NTSB) issued to the FAA: (1) A-10-64 and (2) A-10-65.
ii. Who is potentially affected by this rule?
Aircraft operators and engine manufacturers.
iii. Assumptions
The analysis is conducted in constant dollars with 2016 as
the base year.
Present value estimate follows OMB guidance of a 7 percent
and a 3 percent discount rate.
The analysis period is 27 years with 10 years of new
engine certificates.
Based on the actual production numbers of a common airline
engine, it is estimated that about 220 engines are produced per year
per certification.
The FAA estimates that the average life of an engine is
27,500 cycles (flights) and that engines fly on average 1,748 flights
per year. Therefore, the estimated average service life of an engine is
about 16 years.
The FAA estimates the average fuel consumption will
increase by $750 per year per aircraft.
B. Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (RFA) establishes ``as a
principle of regulatory issuance that agencies shall endeavor,
consistent with the objective of the rule and of applicable statutes,
to fit regulatory and informational requirements to the scale of the
business, organizations, and governmental jurisdictions subject to
regulation.'' To achieve that principle, the RFA requires agencies to
solicit and consider flexible regulatory proposals and to explain the
rationale for their actions. 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 proposed or
final rule would have a significant economic impact on a substantial
number of small entities. If the agency determines that it would, the
agency must prepare a regulatory flexibility analysis as described in
the Act. Two groups would be affected by this rule: aircraft operators
and engine manufacturers.
The FAA believes that this proposed rule would not have a
significant economic impact on small aircraft operators. Affected
operators would incur higher fuel burn costs due to increase in engine
weight (heavier blading/components) and resultant consequent increase
in total aircraft weight. The FAA estimates fuel burn costs of $750 per
year per aircraft, which would not result in a significant economic
impact for small aircraft operators.
Similarly, the FAA believes that this proposed rule would not have
a significant economic impact on engine manufacturers. The FAA
identified one out of five engine manufacturers that meets the Small
Business Administration definition of a small entity. The annual
revenue estimate for this manufacturer is about $75 million.\9\ The FAA
then compared that manufacturer's revenue with its annualized
compliance cost. The FAA expects that the manufacturer's projected
annualized cost of complying with this rule would be 0.7 percent of its
annual revenue,\10\ which is not a significant economic impact.
---------------------------------------------------------------------------
\9\ Source: http://www.manta.com.
\10\ Ratio = annualized cost/annual revenue = $557,459/
$74,800,000 = 0.7 percent.
---------------------------------------------------------------------------
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 the protection of safety, and does not operate in a
manner that excludes imports that meet this objective. The statute also
requires consideration of international standards and, where
appropriate, that they be the basis for U.S. standards. The FAA has
assessed the potential effect of this proposed rule and determined that
it has legitimate domestic safety objectives and would harmonize with
forthcoming EASA standards. Accordingly, this proposed 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 million in lieu of $100
million. This proposed 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. According to the 1995
amendments to the Paperwork Reduction Act (5 CFR 1320.8(b)(2)(vi)), an
agency may not collect or sponsor the collection of information, nor
may it impose an information collection requirement unless it displays
a currently valid Office of Management and Budget (OMB) control number.
The FAA has determined that there would be no new requirement for
information collection associated with this proposed rule.
F. International Compatibility
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. The proposed regulation
is harmonized with changes the European Aviation Safety Agency (EASA)
plans to make to its certification specifications.
G. Environmental Analysis
FAA Order 1050.1F 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
[[Page 31486]]
paragraph 5-6.6(f) and involves no extraordinary circumstances.
H. Regulations Affecting Intrastate Aviation in Alaska
Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat.
3213) requires the FAA, when modifying its regulations in a manner
affecting intrastate aviation in Alaska, to consider the extent to
which Alaska is not served by transportation modes other than aviation,
and to establish appropriate regulatory distinctions. The FAA has
determined that this rule would not affect intrastate aviation in
Alaska.
V. Executive Order Determinations
A. Executive Order 13132, Federalism
The FAA has analyzed this proposed rule under the principals and
criteria of Executive Order 13132, Federalism. The agency has
determined that this action would 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, would not have
federalism implications.
B. Executive Order 13211, Regulations That Significantly Affect Energy
Supply, Distribution, or Use
The FAA analyzed this proposed rule under Executive Order 13211,
Actions Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use (May 18, 2001). The FAA has determined that it
would not be a ``significant energy action'' under the executive order
and would not be likely to have a significant adverse effect on the
supply, distribution, or use of energy.
C. Executive Order 13609, International Cooperation
Executive Order 13609, Promoting International Regulatory
Cooperation, (77 FR 26413, May 4, 2012) promotes international
regulatory cooperation to meet shared challenges involving health,
safety, labor, security, environmental, and other issues and reduce,
eliminate, or prevent unnecessary differences in regulatory
requirements. The FAA has analyzed this action under the policy and
agency responsibilities of Executive Order 13609, Promoting
International Regulatory Cooperation. The FAA has determined that this
action would eliminate differences between U.S. aviation standards and
those of other civil aviation authorities, by ensuring that Sec. 33.76
remains harmonized with EASA CS-E 800.
D. Executive Order 13771, Reducing Regulation and Controlling
Regulatory Costs
Executive Order 13771 titled ``Reducing Regulation and Controlling
Regulatory Costs,'' directs that, unless prohibited by law, whenever an
executive department or agency publicly proposes for notice and comment
or otherwise promulgates a new regulation, it shall identify at least
two existing regulations to be repealed. In addition, any new
incremental costs associated with new regulations shall, to the extent
permitted by law, be offset by the elimination of existing costs. Only
those rules deemed significant under section 3(f) of Executive Order
12866, ``Regulatory Planning and Review,'' are subject to these
requirements.
This proposed rule is not expected to be an E.O. 13771 regulatory
action because this proposed rule is not significant under E.O. 12866.
VI. Additional Information
A. Comments Invited
The FAA invites interested persons to participate in this
rulemaking by submitting written comments, data, or views. The agency
also invites comments relating to the economic, environmental, energy,
or federalism impacts that might result from adopting the proposals in
this document. The most helpful comments reference a specific portion
of the proposal, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, commenters should send only one copy of written
comments, or if comments are filed electronically, commenters should
submit only one time. Commenters must identify the docket or notice
number of this rulemaking.
The FAA will file in the docket all comments received, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rule. Before acting on this action, the FAA
will consider all comments it receives on or before the closing date
for comments. The FAA will consider comments filed after the comment
period has closed if it is possible to do so without incurring expense
or delay. The agency may change this proposal in light of the comments
it receives.
Proprietary or Confidential Business Information: Commenters should
not file proprietary or confidential business information in the
docket. Such information must be sent or delivered directly to the
person identified in the FOR FURTHER INFORMATION CONTACT section of
this document, and marked as proprietary or confidential. If submitting
information on a disk or CD ROM, mark the outside of the disk or CD
ROM, and identify electronically within the disk or CD ROM the specific
information that is proprietary or confidential.
Under 14 CFR 11.35(b), if the FAA is aware of proprietary
information filed with a comment, the agency does not place it in the
docket. It is held in a separate file to which the public does not have
access, and the FAA places a note in the docket that it has received
it. If the FAA receives a request to examine or copy this information,
it treats it as any other request under the Freedom of Information Act
(5 U.S.C. 552). The FAA process such a request under Department of
Transportation procedures found in 49 CFR part 7.
B. Availability of Rulemaking Documents
An electronic copy of rulemaking documents may be obtained from the
internet by
1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
2. Visiting the FAA's Regulations and Policies web page at http://www.faa.gov/regulations_policies or
3. Accessing the Government Printing Office's web page at http://www.access.gpo.fdsys/.
Copies may also be obtained by sending a request to the Federal
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence
Avenue SW, Washington, DC 20591, or by calling (202) 267-9680.
Commenters must identify the docket or notice number of this
rulemaking.
All documents the FAA considered in developing this proposed rule,
including economic analyses and technical reports, may be accessed from
the internet through the Federal eRulemaking Portal referenced in item
(1) above.
List of Subjects in 14 CFR Part 33
Bird ingestion.
The Proposed Amendment
In consideration of the foregoing, the Federal Aviation
Administration proposes to amend chapter I of title 14, Code of Federal
Regulations as follows:
PART 33--AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES
0
1. The authority citation for part 33 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
[[Page 31487]]
0
2. Amend Sec. 33.76 by revising paragraph (a)(1) and adding paragraph
(e) to read as follows:
Sec. 33.76 Bird ingestion.
(a) * * *
(1) Except as specified in paragraph (d) or (e) of this section,
all ingestion tests must be conducted with the engine stabilized at no
less than 100-percent takeoff power or thrust, for test day ambient
conditions prior to the ingestion. In addition, the demonstration of
compliance must account for engine operation at sea level takeoff
conditions on the hottest day that a minimum engine can achieve maximum
rated takeoff thrust or power.
* * * * *
(e) Core engine flocking bird test. Except as provided in paragraph
(e)(4) of this section, for turbofan engines, an engine test must be
performed in accordance with either paragraph (e)(1) or (2) of this
section. The test specified in paragraph (e)(2) may be used to satisfy
this requirement only if testing or validated analysis shows that no
bird material will be ingested into the engine core during the test
under the conditions specified in paragraph (e)(1).
(1) 250-knot climb core engine flocking bird test:
(i) Test requirements are as follows:
(A) Before ingestion, the engine must be stabilized at the
mechanical rotor speed of the first exposed fan stage or stages that,
on a standard day, produces the lowest expected power or thrust
required during climb through 3,000 feet above ground level.
(B) Bird weight must be the largest specified in Table 2 of this
section for the engine inlet area.
(C) Ingestion must be at 250-knots bird speed.
(D) The bird must be aimed at the first exposed rotating fan stage
or stages, at the blade airfoil height, as measured at the leading edge
that will result in maximum bird material ingestion into the engine
core.
(ii) Ingestion of a flocking bird into the engine core under the
conditions prescribed in paragraph (e)(1)(i) of this section must not
cause any of the following:
(A) Sustained power or thrust reduction to less than 50 percent
maximum rated takeoff power or thrust during the run-on segment
specified under paragraph (e)(1)(iii)(B) of this section, that cannot
be restored only by movement of the power lever.
(B) Sustained power or thrust reduction to less than flight idle
power or thrust during the run-on segment specified under paragraph
(e)(1)(iii)(B) of this section.
(C) Engine shutdown during the required run-on demonstration
specified in paragraph (e)(1)(iii) of this section.
(D) Conditions specified in Sec. 33.75(g)(2).
(iii) The following test schedule must be used (power lever
movement between conditions must occur within 10 seconds or less,
unless otherwise noted):
Note to paragraph (e)(1)(iii) introductory text: Durations
specified are times at the defined conditions.
(A) Ingestion.
(B) Followed by 1 minute without power lever movement.
(C) Followed by power lever movement to increase power or thrust to
not less than 50 percent maximum rated takeoff power or thrust, if the
initial bird ingestion resulted in a reduction in power or thrust below
that level.
(D) Followed by 13 minutes at not less than 50 percent maximum
rated takeoff power or thrust. Power lever movement in this condition
is unlimited.
(E) Followed by 2 minutes at 30-35 percent maximum rated takeoff
power or thrust. Power lever movement in this condition is limited to
10 seconds or less.
(F) Followed by 1 minute with power or thrust increased from that
set in paragraph (e)(1)(iii)(E) of this section, by 5-10 percent
maximum rated takeoff power or thrust.
(G) Followed by 2 minutes with power or thrust reduced from that
set in paragraph (e)(1)(iii)(F) of this section, by 5-10 percent
maximum rated takeoff power or thrust.
(H) Followed by 1 minute minimum at ground idle.
(I) Followed by engine shutdown.
(2) 200-knot approach flocking bird core engine test (performed
only if test or analysis shows no bird material will be ingested into
the core during the test at the conditions of paragraph (e)(1) of this
section):
(i) Test requirements are as follows:
(A) Before ingestion, the engine must be stabilized at the
mechanical rotor speed of the first exposed fan stage or stages when on
a standard day the engine thrust is set at approach idle thrust when
descending 3,000 feet above ground level.
(B) Bird mass and weight must be the largest specified in Table 2
of this section for the engine inlet area.
(C) Ingestion must be 200-knot bird speed.
(D) Bird must be aimed at the first exposed rotating fan stage or
stages, at the blade airfoil height measured at the leading edge that
will result in maximum bird material ingestion into the engine core.
(ii) Ingestion of a flocking bird into the engine core under the
conditions prescribed in paragraph (e)(2)(i) of this section may not
cause any of the following:
(A) Power or thrust reduction to less than flight idle power or
thrust during the run-on segment specified under paragraph
(e)(2)(iii)(B) of this section.
(B) Engine shutdown during the required run-on demonstration
specified in paragraph (e)(2)(iii) of this section.
(C) Conditions specified in Sec. 33.75(g)(2).
(iii) The following test schedule must be used (power lever
movement between conditions must occur within 10 seconds or less,
unless otherwise noted):
Note to paragraph (e)(2)(iii) introductory text: Durations
specified are times at the defined conditions.
(A) Ingestion.
(B) Followed by 1 minute without power lever movement.
(C) Followed by 2 minutes at 30-35 percent maximum rated takeoff
power or thrust.
(D) Followed by 1 minute with power or thrust increased from that
set in paragraph (e)(2)(iii)(C) of this section, by 5-10 percent
maximum rated takeoff power or thrust.
(E) Followed by 2 minutes with power or thrust reduced from that
set in paragraph (e)(2)(iii)(D) of this section, by 5-10 percent
maximum rated takeoff power or thrust.
(F) Followed by 1-minute minimum at ground idle.
(G) Followed by engine shutdown.
(3) Applicants must show that an unsafe condition will not result
if any engine operating limit is exceeded during the run-on period.
(4) The core engine flocking bird test of this paragraph (e) may be
combined with the MFB test of paragraph (c) of this section, if the
climb fan rotor speed calculated in paragraph (e)(1) of this section is
within 1 percent of the first fan stage rotor speed required by
paragraph (c)(1) of this section. As used in this paragraph (e)(4),
``combined'' means that, instead of separately conducting the tests
specified in paragraphs (c) and (e) of this section, the test conducted
under paragraph (c) of this section satisfies the requirements of this
section if the bird aimed at the core of the engine meets the bird
ingestion speed criteria of either:
(i) Paragraph (e)(1)(i)(C) of this section; or
(ii) Paragraph (e)(2)(i)(C) of this section if testing or validated
analysis shows that no bird material will be ingested into the engine
core during the test.
[[Page 31488]]
Issued in Washington, DC, on June 21, 2018.
David W. Hempe,
Deputy Executive Director for Regulatory Operations, Aircraft
Certification Service.
[FR Doc. 2018-14270 Filed 7-5-18; 8:45 am]
BILLING CODE 4910-13-P