E6-11373. Airworthiness Standards; Engine Bird Ingestion

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

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 http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://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: [phone].
• Hand Delivery: 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 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 http://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 http://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 [phone]; facsimile [phone]; e-mail [e-mail].

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 http://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 (http://dms.dot.gov/​search);

(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.gpoaccess.gov/​fr/​index.html.

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 [phone]. 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, § 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 § 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 requirements of § 21.101, Designation of Applicable Regulations for Changes to Type Certificates.

Background

The EHWG reviewed the current § 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 § 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 § 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 § 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 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.

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 § 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 § 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 § 33.76. As a result, the current requirements of § 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 § 33.76). The working group also specified that during the test the following parameters be met: for the first minute after 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 § 33.76 (for these size engines) already supports meeting the safety objective proposed for this rulemaking. Therefore, the current requirements of § 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 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 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 § 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:

§ 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 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 § 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.