Airworthiness Standards; Engine Bird Ingestion, 41184-41192 [E6-11373]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 71, Number 139 (Thursday, July 20, 2006)]
[Proposed Rules]
[Pages 41184-41192]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-11373]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 33

[Docket No. FAA-2006-25375; Notice No. 06-09]
RIN 2120-AI73


Airworthiness Standards; Engine Bird Ingestion

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA is proposing to amend the aircraft turbine engine type 
certification standards to reflect recent analysis of the threat 
flocking birds present to turbine engine aircraft. These proposed 
changes would also harmonize FAA, Joint Aviation Authority (JAA), and 
European Aviation Safety Agency (EASA) bird ingestion standards for 
aircraft turbine engines type certificated by the United States and the 
JAA/EASA countries, and simplify airworthiness approvals for import and 
export. These proposed changes are necessary to establish uniform 
international standards that provide an adequate level of safety for 
aircraft turbine engines with respect to the current large flocking 
bird threat.

DATES: Send your comments on or before September 18, 2006.

ADDRESSES: You may send comments [identified by Docket Number FAA-2006-
25375] using any of the following methods:
     DOT Docket Web site: Go to https://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to https://
www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: 1-202-493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building,

[[Page 41185]]

400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For more information on the rulemaking process, see the 
SUPPLEMENTARY INFORMATION section of this document.
    Privacy: We will post all comments we receive, without change, to 
https://dms.dot.gov, including any personal information you provide. For 
more information, see the Privacy Act discussion in the SUPPLEMENTARY 
INFORMATION section of this document.
    Docket: To read background documents or comments received, go to 
https://dms.dot.gov at any time or to Room PL-401 on the plaza level of 
the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Marc Bouthillier, Rulemaking and 
Policy Branch, Engine and Propeller Directorate, ANE-111, Federal 
Aviation Administration, 12 New England Executive Park, Burlington, 
Massachusetts 01803; telephone (781) 238-7196; facsimile (781) 238-
7199; e-mail marc.bouthillier@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites interested persons to participate in this 
rulemaking by submitting written comments, data, or views. We also 
invite 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. We ask that you send us two copies of written 
comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. The docket is available for public 
inspection before and after the comment closing date. If you wish to 
review the docket in person, go to the address in the ADDRESSES section 
of this preamble between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. You may also review the docket using the 
Internet at the Web address in the ADDRESSES section.
    Privacy Act: Using the search function of our docket Web site, 
anyone can find and read the comments received into any of our dockets, 
including the name of the individual sending the comment (or signing 
the comment on behalf of an association, business, labor union, etc.). 
You may review DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78) or you may visit 
https://dms.dot.gov.
    Before acting on this proposal, we will consider all comments we 
receive on or before the closing date for comments. We will consider 
comments filed late if it is possible to do so without incurring 
expense or delay. We may change this proposal in light of the comments 
we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it to you.

Proprietary or Confidential Business Information

    Do not file in the docket information that you consider to be 
proprietary or confidential business information. Send or deliver this 
information directly to the person identified in the FOR FURTHER 
INFORMATION CONTACT section of this document. You must mark the 
information that you consider proprietary or confidential. If you send 
the information on a disk or CD-ROM, mark the outside of the disk or 
CD-ROM and also identify electronically within the disk or CD-ROM the 
specific information that is proprietary or confidential.
    Under 14 CFR 11.35(b), when we are aware of proprietary information 
filed with a comment, we do not place it in the docket. We hold it in a 
separate file to which the public does not have access, and place a 
note in the docket that we have received it. If we receive a request to 
examine or copy this information, we treat it as any other request 
under the Freedom of Information Act (5 U.S.C. 552). We process such a 
request under the DOT procedures found in 49 CFR part 7.

Availability of Rulemaking Documents

    You can get an electronic copy using the Internet by:
    (1) Searching the Department of Transportation's electronic Docket 
Management System (DMS) Web page (https://dms.dot.gov/search);
    (2) Visiting the FAA's Regulations and Policies Web page at https://
www.faa.gov/regulations_policies/; or
    (3) Accessing the Government Printing Office's Web page at https://
www.gpoaccess.gov/fr/.
    You can also get a copy 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. Make 
sure to identify the docket number, notice number, or amendment number 
of this rulemaking.

Executive Summary

    The FAA adopted new regulations under 14 CFR 33.76 on September 5, 
2000, to better address the overall bird ingestion threat. These 
requirements were adopted, in part, as a response to a National 
Transportation Safety Board (NTSB) recommendation (Number A-76-64), 
which recommended an increase in the level of bird ingestion capability 
for aircraft engines. These requirements were published as Amendment 20 
to part 33, Sec.  33.76, in December 2000.
    In that final rule, the FAA also agreed to study the bird threat 
further and to consider additional rulemaking to address larger 
flocking birds, since certification requirements did not address the 
threat that either birds bigger than 1.15 kg (2.5 lbs) or their growing 
population, presented to engine operational safety. In 2001, the FAA 
initiated a contract to collect and analyze data, and reported its 
findings in DOT/FAA Report No. DOT/FAA/AR-TN03/60, ``Study of Bird 
Ingestions into Aircraft Turbine Engines (1968-1999)''. The report 
summarized the historical bird threat and resulting impact to flight 
safety, based on bird ingestion data collected and analyzed for the 30-
year period ending in 1999.
    The Transport Airplane and Engine Issues Group (TAEIG), and its 
Engine Harmonization Working Group (EHWG) utilized the report discussed 
above and reported back to the FAA's Aviation Rulemaking Advisory 
Committee (ARAC) on January 6, 2003 with its results and its proposed 
additional part 33 requirements. The ARAC adopted the working group's 
recommendations. This NPRM reflects the ARAC recommendations.
    The ARAC's proposed revision to Sec.  33.76 would add a new 
requirement that addresses large flocking birds weighing more than 1.15 
kg (2.5 lbs) and up to 3.65 kg (8 lbs). The proposal contains extensive 
common language between part 33 and JAR-E (now CS-E). However, these 
strengthened requirements for the certification of the engines may not 
be adequate to meet the safety objective in the future, if the quantity 
of these birds or their movement near airports significantly increases 
when compared to the present situation.
    This proposed rule may be considered safety significant relative to 
the

[[Page 41186]]

requirements of Sec.  21.101, Designation of Applicable Regulations for 
Changes to Type Certificates.

Background

    The EHWG reviewed the current Sec.  33.76 bird ingestion 
requirements, related advisory material, and the current bird threat. 
It considered the industry data concerning bird threat trend analysis, 
including all reasonably predictable changes to the current threat, and 
if the current rule adequately meets its stated safety objective. The 
working group also considered potential changes in the threat from 
increased populations of particular bird species, actions intended to 
control populations around airports, and flight-crew training for 
flocking-bird recognition and avoidance. Finally, the working group 
recommended changes to Sec.  33.76 and the corresponding JAR-E 
regulation to address inadequacies in the current rule and related 
advisory material.
    The recommendations are based on the following:

Industry Study

    The industry study covers a thirty year period of worldwide non-
military service experience of small, medium and large turbofan and 
turbojet engines, including two, three and four engine aircraft, over 
325 million aircraft departures, and about 340 events involving 
ingestions of large flocking birds (over 1.15 kg [2.5 lbs mass]). The 
study did not include data from aircraft manufactured or flown in the 
former Soviet Union and Eastern European countries, since that data was 
unavailable.
    The study concluded that the proposed rule should address the dual-
engine power loss hazard, since the data indicated that more-than-two-
engine loss of power events are extremely improbable. The study also 
produced a characterization of the threat and consequences of bird 
ingestion. As a result of that analysis, the ARAC identified flocking 
bird encounter threats more severe than specifically addressed under 
current Sec.  33.76. Throughout the study, birds were identified by 
species, and an average mass for that species was assigned. All 
references to bird mass reflect the average mass for the species 
classification. The following are summaries for different inlet throat 
areas.
    1. Observations for Turbine Engines With Inlet Throat Areas Larger 
Than 3.9 m2:
     No multi-engine power loss events with catastrophic 
aircraft consequences involving birds larger than 1.15 kg (2.5 lbs) 
have occurred. However, these events are currently predicted to occur 
at the rate of 1E-9 per aircraft flight hour, based on the power loss 
probabilities for smaller size engines. This is a conservative 
approach, since the power loss probability for this size engine is 
expected to be better than the smaller engines because of their 
inherently more robust design regarding foreign object damage, and 
because there was not enough service history data for this size engine 
to calculate the probability without considering the smaller size 
engine data.
     No multi-engine ingestion events for bird classifications 
larger than 1.15 kg (2.5 lbs) have occurred.
    2. Observations for Turbine Engines With Inlet Throat Areas Between 
3.5 and 3.9 m2:
     No multi-engine power loss events with catastrophic 
aircraft consequences involving birds larger than 1.15 kg (2.5 lbs) 
have occurred. However, these events are currently predicted to occur 
at the rate of about 1.1E-9 per aircraft flight hour.
     Multi-engine ingestions of flocking birds larger than 1.15 
kg (2.5 lbs) have occurred at a rate of 7.4E-8 per aircraft flight 
hour.
     No multi-engine ingestion events for bird classifications 
larger than 3.65 kg (8 lbs) have occurred.
    3. Observations for Turbine Engines With Inlet Throat Areas Between 
2.5 and 3.5 m2:
     No multi-engine power loss events with catastrophic 
aircraft consequences have occurred with birds larger than 1.15 kg (2.5 
lbs). However, these events are currently predicted to occur at the 
rate of 1.5E-9 per aircraft flight hour.
     Multi-engine ingestions of flocking birds larger than 1.15 
kg (2.5 lbs) have occurred at a rate of 2.2E-8 per aircraft flight 
hour.
     No multi-engine ingestion events for bird classifications 
larger than 1.5 kg (3.3 lbs) have occurred.
    4. Observations for Turbine Engines With Inlet Throat Areas Between 
1.35 and 2.5 m2:
     No multi-engine power loss events with catastrophic 
aircraft consequences have occurred with birds larger than 1.15 kg (2.5 
lbs). However these events are currently predicted to occur at the rate 
of 2.8E-10 per aircraft flight hour.
     No multi-engine ingestions of flocking birds larger than 
1.15 kg (2.5 lbs) have occurred (one ground event did occur after 
landing).
    5. Observations for Turbine Engines With Inlet Throat Areas Between 
0.40 and 1.35 m2:
     One multi-engine power loss event involving a bird mass 
less than 1.15 kg (2.5 lbs) with catastrophic aircraft consequences has 
occurred for transport category airplanes, and four for business jet 
applications.
     Multi-engine ingestions of flocking birds larger than 1.15 
kg (2.5 lbs) have occurred at a rate of 1.8E-8 per aircraft flight hour 
for large transport category aircraft. Data for business jets were 
incomplete and therefore no rate was calculated.
     No multi-engine ingestion events for bird classifications 
larger than 3.65 kg (8 lbs) have occurred.
    6. Observations for Turbine Engines With Inlet Throat Areas Less 
Than 0.40 m2:
     No multi-engine power loss events with catastrophic 
aircraft consequences with birds larger than 1.15 kg (2.5 lbs) have 
occurred in service. No multi-engine power loss events involving a bird 
mass less than 1.15 kg with catastrophic aircraft consequences have 
occurred involving transport category aircraft. Of the data provided on 
business jets, three multi-engine power loss events involving a bird 
mass less than 1.15 kg with catastrophic aircraft consequences have 
occurred.
     Transport category aircraft multi-engine ingestions of 
flocking birds (of all mass sizes) have been reported to occur at a 
rate of 3.2E-8 per engine hour.
     No multi-engine ingestion events for bird classifications 
larger than 1.15 kg (2.5 lbs mass) have been reported.
    The study concluded that currently certified engine designs might 
suffer a hazardous condition from large flocking bird ingestion at a 
rate slightly higher than desired. This conclusion led the ARAC to 
recommend new certification test requirements to achieve the safety 
objective discussed below, on a fleet wide basis.

Proposed Rule Safety Objective

    Flocking birds may be ingested by more than one engine on the 
aircraft during one encounter. The objective of this proposed rule is 
to define certification criteria such that the predicted rate of 
catastrophic aircraft events due to multi-engine power loss resulting 
from multi-engine ingestion of flocking birds weighing between 1.15 kg 
(2.5 lbs) and 3.65 kg (8 lbs) does not exceed 1E-9 events per aircraft 
flight hour. A catastrophic aircraft event might occur when damage to 
the engines results in an unsafe condition as specified in Sec.  33.75; 
or where insufficient total aircraft power, thrust or engine 
operability is retained to provide adequate engine run-on capability 
for continued safe flight and landing of the aircraft. The study

[[Page 41187]]

concluded that it is not possible to demonstrate by a single test that 
any given engine design will experience no more than one multi-engine 
failure with catastrophic consequences to the aircraft due to ingestion 
of large flocking birds in 1E9 hours of fleet experience. However, the 
study did conclude that a design requirement that will provide the 
basis for predicting that level of reliability on a fleet wide basis is 
possible, based on the following assumptions:
     Current bird control standards for airport certification 
will be maintained.
     Airport operators, air traffic controllers, and pilots 
will maintain their current awareness of, and mitigation proficiencies 
for, the bird ingestion threat.
     Any increase in the large flocking bird multi-engine 
ingestion rate over the next ten years will not exceed values estimated 
from the current bird growth rate observed in the data study.
    The safety objective for this proposed rule is applied at the world 
fleet level. The world fleet of turbine powered airplanes is comprised 
of two, three, and four engine airplanes. The large engine historical 
fleet experience of multi-engine ingestions is dominated by three and 
four engine airplane data, however two engine airplanes are likely to 
dominate the future fleet. The working group considered this evolving 
situation within this rulemaking effort, with assumptions about future 
fleet makeup playing a role in the selection of possible new 
requirements.
    With respect to bird ingestion, differences between these aircraft 
types generally relate to either the multi-engine bird ingestion rate, 
or the probability of a hazardous consequence given an actual dual-
engine power loss. For example, twin-engine airplanes will have a 
higher probability of a hazardous consequence given an actual dual-
engine power loss; however their multi-engine bird ingestion rate (and 
resulting power loss) is much lower than that of the three- and four-
engine airplanes. Conversely, three- and four-engine airplanes, while 
having substantially higher rates of multi-engine bird ingestion (and 
resulting power loss), are less likely to suffer a hazardous 
consequence should a dual-engine power loss actually occur.
    The EHWG review of world fleet service data collected as part of 
the industry study indicates that the higher rate of multi-engine bird 
ingestion occurrences for three- and four-engine airplanes dominates 
the rate for the entire fleet of large engines. This proposed 
rulemaking is therefore, based on the current world fleet distribution 
of two, three, and four engine airplanes in determining the potential 
new requirements necessary to meet the safety objective.
    Since the world fleet of large engines is becoming increasingly 
populated with two engine airplanes, the proposed performance 
requirements will become more conservative and provide an even higher 
level of safety with respect to the multi-engine bird ingestion threat 
to airplanes in service for these size engines. For small and medium 
size engines, the world fleet is overwhelmingly made up of twin-engine 
airplanes. This situation is not likely to change over time. Therefore 
the multi-engine ingestion rate data for large size engines reflects 
the current fleet makeup.

Proposed Rule Parameter Selection

    The EHWG concluded that to establish the test conditions that 
satisfy the safety objective, a probability analysis was needed. The 
probability of a dual-engine power loss given a dual-engine ingestion 
involves considerations of dependent and independent conditions. During 
a flock encounter, both engines are traveling at the same forward speed 
(that of the aircraft) and will be at the same power setting, creating 
a dependent condition. The independent conditions involve the details 
of the actual impact of the bird with the engine. Because of the 
combination of dependent and independent conditions involved in the 
analysis, simple numeric relationships for determining dual-engine 
power loss probabilities would not be appropriate. Therefore the 
working group selected a Monte Carlo simulation as the best tool to use 
for this analysis. The selection of controlling parameters for the 
analysis and a description of the analysis techniques are discussed 
below.
    The EHWG recommendation identified the need to design a test that 
is representative of in-service combinations of critical ingestion 
parameters. Therefore, engine ingestion parameters for actual events 
resulting in sustained power loss were evaluated by the EHWG. The 
working group found that the most critical parameters that affect power 
loss are bird mass, bird speed, impact location, and engine power 
setting. They concluded that since testing for all possible 
combinations of parameters is impractical, defining a single 
certification test that will support meeting the safety objective was 
necessary. The working group defined this test requirement by using a 
Monte Carlo statistical analysis to show that the engine test covers a 
sufficient percentage of possible critical parameter combinations so as 
to support meeting the safety objective for birds in the 1.15 kg (2.5 
lbs) to 3.65 kg (8 lbs) mass range.
    The EHWG used the study to determine the probability of a 
catastrophic consequence to an aircraft given a dual-engine power loss 
event, and to aid in defining a test that would likely achieve the 
aircraft level fleet safety objective. They took the single engine 
ingestion rate and multi-engine ingestion rates for birds with mass 
larger than 1.15 kg (2.5 lbs) from the data, along with the fleet 
average flight length of 3.2 hours for large engine installations, and 
1.7 hours for small and medium engine installations. The EHWG then used 
historical accident and incident service data to determine an aircraft 
hazard ratio. A hazard ratio is the number of aircraft accidents 
(related to multi-engine power loss) divided by the number of dual-
engine power loss events. A dual-engine power loss is an event where at 
least two engines on an aircraft have a combined thrust loss greater 
than the maximum thrust of one engine. The multi-engine ingestion rate, 
average flight length and hazard ratio were analyzed to establish a 
combination of test parameters and conditions that would be consistent 
with the safety objective.

Hazard Ratio

    To establish a hazard ratio, the FAA provided the EHWG with a list 
describing known multi-engine power loss events for review. The FAA 
data shows a hazard ratio for twin-engine aircraft to be 0.33, and all 
aircraft events to be 0.07. The Aerospace Industries Association (AIA) 
Propulsion Committee Report PC342 (submitted in support of Continued 
Airworthiness Assessment Methodology (CAAM) activity) shows a hazard 
ratio of 0.07 for all aircraft. The Boeing supplied data for large high 
bypass ratio engines shows a hazard ratio of 0.05 for all aircraft. 
Based on the above data, the EHWG selected a hazard ratio of 0.18 for 
all engines. The working group found that this hazard ratio was 
appropriate for the specific data set being utilized. The working group 
achieved similar results when statistical confidence bands of 75 and 90 
percent for each data category were tabulated for comparison. This 
provided confidence that the value selected is appropriate for the 
fleet mix under consideration. For consistency with this single hazard 
ratio approach, the group applied a standard mix of 75-percent two 
engine and 25-percent four engine applications (based on aircraft 
flights) to all engine size classes.

[[Page 41188]]

Monte Carlo Analysis

    A mathematical calculation working backward from the safety 
objective established a fleetwide multi-engine power loss rate that 
would satisfy the overall safety objective of the proposed rule. Then a 
number of Monte Carlo simulations were performed to identify a set of 
bird ingestion test conditions that would, if demonstrated during type 
certification, produce a fleetwide dual-engine power loss rate that 
supports the desired safety objective of the proposal.
    The Monte Carlo simulations involved entering bird strike impact 
energy into the first stage rotor in accordance with variations of the 
ingestion parameters determined by service data probability curves. 
These parameters are noted below. Initial simulations defined a 
parameter boundary created by the current and proposed certification 
requirements (independent of fan blade or overall engine design) that 
would meet the safety objective.
    The Monte Carlo simulation used random inputs of the following 
parameters:
     Takeoff or approach phase ingestion probabilities 
established from the data study (The data study showed an even 50-
percent split between takeoff and approach encounters).
     Engine takeoff power first stage rotor speed based on 
actual service data.
     Impact location on the engine fan face based on area.
     Aircraft forward speed based on actual service data.
     The bird size based on a probability distribution 
established from the data study for birds larger than 1.15 kg (2.5 lbs) 
but less than or equal to 3.65 kg (8 lbs).
    The Monte Carlo simulations also accounted for installation effects 
at the fan blade tip (tip shielding). An installed engine is generally 
shielded by the nacelle structure, particularly the inlet cowl, which 
reduces the exposure of the fan blade tip from direct impact by large 
birds. The reduction in the exposed diameter is close to 10 percent, 
but varies slightly with the engine diameter.
    The engine structure considered in the analysis consists of any 
inlet structure that can be impacted by an ingested bird, including but 
not limited to inlet guide vanes, spinners, and fairings. Static engine 
inlet structure that would be certified as part of the engine, and 
which could be impacted by a bird prior to the bird striking the first 
rotating stage of an engine compressor was also evaluated in the 
analysis. Of particular interest was the fan fairing (for example, 
spinner or bullet nose), that directs inlet air around the fan hub into 
the core or fan bypass airflows. With current technology, this fairing 
is approximately one third of the diameter of the fan, which is 
approximately 11-percent of the fan area. The data shows that this 
fairing is impacted in service by birds in proportion to its area. The 
data also shows that fairings certified with engines to the 
requirements of Sec.  33.77 (Amendment 33-6) have not caused an engine 
power loss from impacts due to birds of any size, including large 
flocking birds. The current requirement of Sec.  33.76 requires that 
the fairing demonstrate capability for 1.15 kg (2.5 lbs) birds at the 
critical location at 250 knots impact speed. The requirements for the 
fairing, with conservative allowance for the size of the critical area 
of the fairing, were entered into the Monte Carlo analysis. The Monte 
Carlo analysis included impacts to the fairing as well as the fan 
blades for the overall evaluation. The results of the Monte Carlo 
analysis showed the safety target could be met for inlet components 
meeting the current requirements of Sec.  33.76. As a result, the 
current requirements of Sec.  33.76 appear to provide acceptable 
standards, and no additional rulemaking is contemplated for these 
classes of components. However, the working group decided to revise the 
Advisory Circular to clarify what the current requirements and 
acceptable methods of compliance are for inlet components.

Test Conditions and Results

    The following test conditions are proposed based on the above 
analysis:
    1. Power, Thrust & Rotor Speeds: The first stage of rotating blades 
of the engine is the feature of a typical turbine engine most 
susceptible to damage from large flocking birds which can result in 
loss of engine power. The working group determined that selecting a 
first stage rotor speed that most engines were likely to be at during 
takeoff would support meeting the safety objective. Analysis of 
manufacturer collected service data, which includes de-rated thrust 
operations for the world fleet, showed that this first stage rotor 
speed, on a fleet average basis, corresponds to 90 percent of maximum 
rated takeoff power or thrust on an International Standard Atmosphere 
(ISA) standard day. Therefore, the thrust or power setting for the 
proposed test demonstration is based on first stage rotor speed itself, 
which will be equal to a rotor speed that corresponds to engine 
operation at 90 percent of maximum rated takeoff power or thrust on an 
ISA standard day.
    2. Bird Speed: The speed of the bird during the proposed test 
represents the speed of the aircraft at the time of ingestion. 
Ingestions that occur at speeds lower than flight speeds generally 
result in rejected takeoffs, and are usually less hazardous to the 
aircraft. Flight speeds at altitudes where large flocking birds are 
most likely encountered generally range between 150 and 250 knots. 
Damage to an engine due to a bird ingestion is a result of a 
combination of parameters that include ingestion speed, first stage 
rotor speed, and location of impact on the rotor blade span. For most 
turbine engine designs, analysis showed that a bird speed less than 250 
knots is generally more conservative. The data shows that the most 
representative aircraft speed for encounters with large flocking birds 
is approximately 200 knots. The working group therefore, used 200 knots 
as the impact speed for the test demonstration.
    3. Target Location: The Monte Carlo simulations showed that a test 
with bird impact at 50 percent of fan blade height or greater, in 
conjunction with the other test parameters described above, supports 
meeting the required safety objective of the rule. This aspect of the 
overall analysis assumes that the first stage blades will be more 
impact tolerant inboard of the 50-percent height location than 
outboard, and that the core ingestion capability is adequately 
addressed under the medium bird requirements. The test demonstration 
will establish the capability level of the first stage rotor at a 
location representing a minimum of half of the exposed area of the 
engine.
    4. Run-on: The proposed run-on demonstration shows that the engine 
is capable of providing the required power, thrust and operability 
after the ingestion event. The engine must be able to continue a take-
off and initial climb, and perform one air turn-back, with a safe 
return for landing. The current procedures recommended by the aircraft 
manufacturers and regulators following an engine malfunction, are for 
flight crews to concentrate on flying the aircraft without throttle 
manipulation, regardless of the nature of an engine malfunction, until 
an altitude of at least 400 ft. is reached. Also, the aircraft would 
have to be flown so that flight crews could maintain the aircraft on 
glide slope. Therefore, the run-on time for the large flocking bird 
ingestion test has been tentatively set at a minimum of 20 minutes (the 
same as for the medium bird requirements of Sec.  33.76). The working 
group also specified that during the test the following parameters be 
met: for the first minute after

[[Page 41189]]

ingestion with no throttle manipulation, the engine must produce at 
least 50-percent maximum rated takeoff thrust; then the engine is to 
maintain no less than 50-percent maximum rated takeoff thrust for the 
next 13 minutes, but the throttle may be manipulated to provide 
opportunity for the aircraft to establish itself in a return approach 
attitude; then a five minute period at approach thrust with a one 
minute thrust bump to demonstrate that a flight crew could establish 
approach thrust/power and manipulate the throttle sufficiently to 
maintain glide slope during approach and landing. The working group 
also specified a final minute where the engine has to demonstrate that 
it can be brought safely to ground idle and shutdown. Also, given the 
potential for significant engine damage and resulting operating 
characteristics effects due to ingestion of birds of this mass, the 
group did not consider it reasonable to require engine re-acceleration 
after landing for thrust reverser use.
    5. Bird Mass and Weight: For engines with inlet throat area larger 
than 3.9 m2 (6045 sq in), a bird size of 2.5 kg (5.5 lbs) is 
representative of the average Snow Goose, one of the species identified 
as a key large flocking bird threat to transport category aircraft. The 
Monte Carlo simulation analysis shows that specifying a 2.5 kg (5.5 
lbs) bird for the certification requirement, tested at the conditions 
specified in the proposed rule, provides adequate mitigation of the 
risk for bird masses larger than 1.15 kg (2.5 lbs), and up to 3.65 kg 
(8 lbs), such that the proposed rule's safety objective is met. This 
determination covers both the current and projected multi-engine 
ingestion rates. Similarly, for engines with an inlet throat area 
between 3.5-3.9 m2 (5425-6045 sq in), the group found that a 
large flocking bird demonstration with a 2.1 kg (4.63 lbs) bird would 
be required to meet the safety objective. For engines with an inlet 
throat area between 2.5-3.5 m2 (3875-5425 sq in), the group 
found that a large flocking bird demonstration with a 1.85 kg (4.08 
lbs) bird would likely be required to meet the safety objective and for 
engines with an inlet throat area of 2.5 m2 (3875 sq in) or 
less, the data review and analysis showed the current requirements of 
Sec.  33.76 (for these size engines) already supports meeting the 
safety objective proposed for this rulemaking. Therefore, the current 
requirements of Sec.  33.76 for engines with inlet throat areas of 2.5 
m2 (3875 sq in) or less would remain unchanged.

TAEIG Recommendation

    The working group concluded that the proposed rule supports 
achieving the target level of safety against the currently identified 
and 10-year projected large flocking bird threat. The EHWG has also 
submitted recommendations relating to the control of Snow and Canada 
geese populations and their movements near airports. The TAEIG 
delivered these recommendations to FAA through an ARAC letter dated 
January 3, 2002.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce, including minimum safety 
standards for aircraft engines. This proposed rule is within the scope 
of that authority because it updates the existing regulations for bird 
ingestion.

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. We have determined that there 
are no current new information collection requirements associated with 
this proposed rule.

International Compatibility

    In keeping with U.S. obligations under the Convention on 
International Civil Aviation, FAA policy is to comply with 
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.

Economic Assessment, Regulatory Flexibility Determination, Trade Impact 
Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic 
analyses. First, Executive Order 12866 directs 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 requires agencies to analyze the 
economic impact of regulatory changes on small entities. Third, the 
Trade Agreements Act (19 U.S.C. 2531-2533) prohibits agencies from 
setting standards that create unnecessary obstacles to the foreign 
commerce of the United States. In developing U.S. standards, this Trade 
Agreements Act requires agencies to consider international standards 
and, where appropriate, to 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). This portion of the 
preamble summarizes the FAA's analysis of the economic impacts of this 
NPRM.
    The Department of Transportation Order DOT 2100.5 prescribes 
policies and procedures for simplification, analysis, and review of 
regulations. If the expected cost impact is so minimal that a proposal 
does not warrant a full regulatory evaluation, this order permits a 
statement to that effect. The basis for the minimal impact must be 
included in the preamble, if a full regulatory evaluation of the cost 
and benefits is not prepared. Such a determination has been made for 
this rule. The reasoning for that determination follows:
    This NPRM would revise FAR 33.76 to harmonize with the current EASA 
CS-E 800. A brief discussion of the concept of harmonization is 
presented below.
    Presently, U.S. turbine engine manufacturers must satisfy the 
certification requirements of both the FAA and the European Aviation 
Safety Agency (EASA) to market turbine engines in both the United 
States and Europe. Meeting two different sets of certification 
requirements can increase the costs of developing turbine engines often 
with no associated safety benefits. In the interests of fostering 
international trade, lowering the cost of aircraft and/or engine 
development, and making the certification process more efficient, the 
FAA, EASA, and equipment manufacturers have been working to create, to 
the maximum extent possible, a uniform set of certification 
requirements accepted in both the United States and Europe. This

[[Page 41190]]

endeavor is referred to as ``harmonization.''
    Prior to 1970, each country had its own aviation standards. 
Therefore, if you wished to certify an engine in another country it was 
necessary to go through that country's certification process in 
addition to your own country's certification process. This resulted in 
a great deal of time and expense if it was desired to certify an engine 
in several countries. It was also felt that it was not necessary 
because many of the standards were similar.
    In 1970, the Cyprus Arrangements created the Joint Aviation 
Authorities (JAA) in Europe. The JAA's purpose was to develop aviation 
standards that would be adopted by the individual European National 
Aviation Authorities (NAA's). The standards that were developed were 
known as the Joint Aviation Regulations (JAR's). However, the JAA had 
no legal status and it was up to each NAA as to whether they would 
adopt the JAR's in whole or in part. Each NAA was also responsible for 
aviation regulation matters in its particular country.
    The successor organization to the JAA is the European Aviation 
Safety Agency (EASA). This organization came into existence on July 15, 
2002 by Regulation (EC) 1592/2002 of the European Parliament and 
Council. The EASA became operational for certification of aircraft, 
engines, parts and appliances on September 28, 2003 by Commission 
Regulation (EC) 1702/2003.
    When the EASA became operational it adopted all appropriate 
regulations including those that were in the process of being revised. 
Because the harmonization process between the proposed part 33.76 and 
the proposed CS-E 800 was almost completed when the EASA became 
operational, the requirements of the proposed part 33.76 and CS-E 800 
are identical. CS-E 800 is now an official rule of a foreign regulatory 
agency while the proposed part 33.76 is still in the Notice of Proposed 
Rulemaking (NPRM) stage. Because CS-E 800 is an official regulation of 
a foreign government agency, according to the Trade Agreements Act of 
1979, it could be used as the basis for an American rule.
    The effect of this proposed rulemaking would be to reduce 
duplication of certification effort, through harmonization, thereby 
narrowing the differences between the U.S. and European regulations, 
because this proposal would create, to the maximum extent possible, a 
single set of certification requirements accepted in the United States 
and Europe. It should be noted that the American aircraft engine 
manufacturers already sell their products in Europe. To do this, the 
American aircraft engine manufacturers already voluntarily meet the 
European standards. Therefore, this proposed rule would have no impact 
on the costs of the American aircraft engine manufacturers.
    The expected outcome of this NPRM is to have a minimal cost impact 
with positive net benefits for the reasons described above. Therefore, 
a detailed regulatory evaluation was not prepared. The FAA requests 
comments with supporting justification regarding the FAA determination 
of minimal impact.
    The FAA has, therefore, determined that this rulemaking action is 
not a ``significant regulatory action'' as defined in section 3(f) of 
Executive Order 12866, and is not ``significant'' as defined in DOT's 
Regulatory Policies and Procedures. In addition, the FAA has determined 
that this rulemaking action: (1) Would not have a significant economic 
impact on a substantial number of small entities; (2) is in compliance 
with the Trade Agreements Act; and (3) would not impose an unfunded 
mandate on state, local, or tribal governments, or on the private 
sector.

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 
consider flexible regulatory proposals, to explain the rationale for 
their actions, and to solicit comments. 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 RFA.
    However, if an agency determines that a proposed or final 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.
    This proposed rule would affect the following U.S. aircraft engine 
manufacturers:
    1. GE Infrastructure Aircraft Engines; a Business Unit of the 
General Electric Co.
    2. The Pratt & Whitney Company; a Division of United Technologies 
Corp.
    The General Electric Company employs 300,000 people and United 
Technologies employs 209,000 people. The Small Business Administration 
(SBA) uses the North American Industry Classification System (NAICS) as 
updated by the Office of Management and the Budget (OMB) in 2002 or 
NAICS 2002 to classify industries and develop size standards. The 
classification for General Electric and United Technologies is NAICS 
2002 Sectors 31-33 Manufacturing; Subsector 336 Transportation 
Equipment; and Aircraft Engine and Parts Manufacturers or Number 
336412. The size standard for a small business aircraft engine 
manufacturer (NAICS 2002 336412) is 1,000 employees.
    All United States engine manufacturers who would be affected by FAR 
part 33.76 exceed the SBA small-entity criteria of 1,000 employees.
    Consequently, the FAA certifies that this rulemaking action would 
not have a significant economic impact on a substantial number of small 
entities. The FAA solicits comments regarding this determination.

Trade Impact Assessment

    The Trade Agreements Act of 1979 prohibits Federal agencies from 
establishing any standards or engaging in related activities that 
create unnecessary obstacles to the foreign commerce of the United 
States. Legitimate domestic objectives, such as safety, are not 
considered unnecessary obstacles. The statute also requires 
consideration of international standards and, where appropriate, that 
they be the basis for U.S. standards.
    Thus this proposed rule is consistent with the Trade Agreements 
Act, as it would use European Aviation Safety Agency standards, as the 
basis for U.S. standards.

Unfunded Mandates Assessment

    The Unfunded Mandates Reform Act of 1995 (the Act) is intended, 
among other things, to curb the practice of imposing unfunded Federal 
mandates on State, local, and tribal governments. Title II of the Act 
requires each Federal agency to prepare a written statement assessing 
the effects of any Federal

[[Page 41191]]

mandate in a proposed or final agency rule that may result in an 
expenditure of $100 million or more (adjusted annually for inflation) 
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 $120.7 million in lieu of $100 million.
    This proposed rule does not contain such a mandate. The 
requirements of Title II of the Act, therefore, do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and 
criteria of Executive Order 13132, Federalism. We have determined that 
this proposed rule would not have a substantial direct effect on the 
States, on the relationship between the national Government and the 
States, or on the distribution of power and responsibilities among the 
various levels of government. Therefore, this proposed rule would not 
have federalism implications.

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 proposed rule qualifies for the categorical exclusion 
identified in Chapter 3, paragraph 312d.

Regulations That Significantly Affect Energy Supply, Distribution, or 
Use

    The FAA has analyzed this NPRM under Executive Order 13211, Actions 
Concerning Regulations that Significantly Affect Energy Supply, 
Distribution, or Use (May 18, 2001). We have determined that it is not 
a ``significant energy action'' under the executive order because it is 
not a ``significant regulatory action'' under Executive Order 12866, 
and it is not likely to have a significant adverse effect on the 
supply, distribution, or use of energy.

List of Subjects in 14 CFR Part 33

    Air Transportation, Aircraft, Aviation Safety, Safety

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

    1. The authority citation for part 33 continues to read as follows:

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

    2. Amend Sec.  33.76 by revising paragraphs (a) introductory text, 
(a)(1), (a)(3), (a)(5), the heading of paragraph (b) introductory text, 
and the heading of paragraph (c) introductory text, and adding 
paragraph (d) to read as follows:


Sec.  33.76  Bird ingestion.

    (a) General. Compliance with paragraphs (b), (c), and (d) of this 
section shall be in accordance with the following:
    (1) Except as specified in paragraph (d) 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.
* * * * *
    (3) The impact to the front of the engine from the large single 
bird, the single largest medium bird which can enter the inlet, and the 
large flocking bird must be evaluated. Applicants must show that the 
associated components when struck under the conditions prescribed in 
paragraphs (b), (c) or (d) of this section, as applicable, will not 
affect the engine to the extent that the engine cannot comply with the 
requirements of paragraphs (b)(3), (c)(6) and (d)(4) of this section.
* * * * *
    (5) Objects that are accepted by the Administrator may be 
substituted for birds when conducting the bird ingestion tests required 
by paragraphs (b), (c) and (d) of this section.
* * * * *
    (b) Large single bird. * * *
    (c) Small and medium flocking bird. * * *
    (d) Large flocking bird. An engine test will be performed as 
follows:
    (1) Large flocking bird engine tests will be performed using the 
bird mass and weights in Table 4, and ingested at a bird speed of 200 
knots.
    (2) Prior to the ingestion, the engine must be stabilized at no 
less than the mechanical rotor speed of the first exposed stage or 
stages that, on a standard day, would produce 90 percent of the sea 
level static maximum rated takeoff power or thrust.
    (3) The bird must be targeted on the first exposed rotating stage 
or stages at a blade airfoil height of not less than 50 percent 
measured at the leading edge.
    (4) Ingestion of a large flocking bird under the conditions 
prescribed in this paragraph must not cause any of the following:
    (i) A sustained reduction of power or thrust to less than 50 
percent of maximum rated takeoff power or thrust during the run-on 
segment specified under paragraph (d)(5)(i) of this section.
    (ii) Engine shutdown during the required run-on demonstration 
specified in paragraph (d)(5) of this section.
    (iii) The conditions specified in paragraph (b)(3) of this section.
    (5) The following test schedule must be used:
    (i) Ingestion followed by 1 minute without power lever movement.
    (ii) Followed by 13 minutes at not less than 50 percent of maximum 
rated takeoff power or thrust.
    (iii) Followed by 2 minutes between 30 and 35 percent of maximum 
rated takeoff power or thrust.
    (iv) Followed by 1 minute with power or thrust increased from that 
set in paragraph (d)(5)(iii) of this section, by between 5 and 10 
percent of maximum rated takeoff power or thrust.
    (v) Followed by 2 minutes with power or thrust reduced from that 
set in paragraph (d)(5)(iv) of this section, by between 5 and 10 
percent of maximum rated takeoff power or thrust.
    (vi) Followed by a minimum of 1 minute at ground idle then engine 
shutdown.
    The durations specified are times at the defined conditions. Power 
lever movement between each condition will be 10 seconds or less, 
except that power lever movements allowed within paragraph (d)(5)(ii) 
are not limited, and for setting power under paragraph (d)(5)(iii) of 
this section will be 30 seconds or less.
    (6) Compliance with the large flocking bird ingestion requirements 
of this paragraph may also be demonstrated by:
    (i) Incorporating the requirements of paragraph (d)(4) and (d)(5) 
of this section, into the large single bird test demonstration 
specified in paragraph (b)(1) of this section; or,
    (ii) Use of an engine subassembly test at the ingestion conditions 
specified in paragraph (b)(1) of this section if:
    (A) All components critical to complying with the requirements of 
paragraph (d) of this section are included in the subassembly test; and
    (B) The components of paragraph (d)(6)(ii)(A) of this section are 
installed in a representative engine for a run-on demonstration in 
accordance with

[[Page 41192]]

paragraphs (d)(4) and (d)(5) of this section; except that section 
(d)(5)(i) is deleted and section (d)(5)(ii) must be 14 minutes in 
duration after the engine is started and stabilized; and
    (C) The dynamic effects that would have been experienced during a 
full engine ingestion test can be shown to be negligible with respect 
to meeting the requirements of paragraphs (d)(4) and (d)(5) of this 
section.
    (7) Applicants must show that an unsafe condition will not result 
if any engine operating limit is exceeded during the run-on period.

                          Table 4 to Sec.   33.76.--Large Flocking Bird Mass and Weight
----------------------------------------------------------------------------------------------------------------
     Engine inlet throat area  m2 (sq in)       Bird quantity            Bird mass and weight  kg (lbs)
----------------------------------------------------------------------------------------------------------------
A <2.50 (3875 sq in).........................            None  .................................................
2.50 (3875 sq in) <=A <3.50 (5425 sq in).....               1  1.85 kg (4.08 lbs).
3.50 (5425 sq in) <=A <3.90 (6045 sq in).....               1  2.10 kg (4.63 lbs).
3.90 (6045 sq in) <=A........................               1  2.50 kg (5.51 lbs).
----------------------------------------------------------------------------------------------------------------


    Issued in Washington, DC, on July 13, 2006.
John J. Hickey,
Director, Aircraft Certification Service.
 [FR Doc. E6-11373 Filed 7-19-06; 8:45 am]
BILLING CODE 4910-13-P