Exemption No. 5451

UNITED STATES OF AMERICA

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

KANSAS CITY, MISSOURI 64106

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* In the matter of the petition of *

*

AERO TWIN, INC. * * Regulatory Docket for an exemption from Section 23.3(a) * No. 090CE and Part 135, Appendix A, * of the Federal Aviation Regulations *

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DENIAL OF PETITION FOR RECONSIDERATION

By letter dated May 7, 1991, Mr. Michael W. Lovett of Aero Twin, Inc. (Aero Twin), 2404 Merrill Field Drive, Anchorage, Alaska 99501, petitioned the Administrator, in accordance with Section 11.55(a) of the Federal Aviation Regulations (FAR), for reconsideration of Denial of Exemption No. 5299 from Section 23.3(a) and Part 135, Appendix A, of the FAR to permit the modification of the single-engine Cessna Model 208B from a nine passenger to a thirteen passenger airplane by the use of Cessna

Modification kit No. CS8-014.

The Petitioner requests relief from the following regulations:

Section 23.3(a) of the FAR, which provides, in pertinent part, that the normal category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less and a maximum certificated weight of 12,500 pounds or less. Part 135, Appendix A, which provides, in pertinent part, the one engine inoperative requirements for Air Taxi and Commercial Operators operating an airplane with 10 or more passenger seats.

The Petitioner supports its request with the following

information:

Aero Twin states that its petition for reconsideration is based upon the existence of additional information that was not presented in the original petition. This information includes data, technical evidence, and additional arguments that the petitioner believes are both logical and qualitative and that support the assertions made in the original petition. Aero Twin

asserts that this additional information was not included in the original petition because it did not understand the level of substantiation required by the FAR. Aero Twin adds that it is not an Air Taxi Operator, but is an aircraft maintenance and modification facility (FAA Repair Station No. FE4R177M). AeroTwin further states its intention to make the exemption available

to all operators of the Cessna Model 208B.

Regarding the issue of the public interest and safety, Aero Twin restates the following assertions and adds further comments.

1. Assertion: Increased passenger capacity decreases the number of flights required to service a given number of

passengers.

Comment: This assertion is self evident.

2. Assertion: Increased passenger capacity decreases air

traffic controller workload.

Comment: Given that increased passenger capacity decreases the number of flights required to service a given number of passengers, and assuming that air traffic controller workload is directly proportional to the number of flights worked, it follows that increased passenger capacity will decrease air traffic controller workload for a given number

of passengers.

3. Assertion: Increased passenger capacity decreases the quantity of fuel used per passenger.

Comment: The percent of increase in takeoff weight will be less than the percent increase in number of passengers when additional passengers are loaded. The fuel used to fly a given route is roughly proportional to takeoff weight. It follows that the percentage increase in fuel used will be less than the percentage increase in number of passengers carried, which means less fuel is burned per passenger as more passengers are carried.

4. Assertion: Increased passenger capacity permits the airplane to be operated at a lower cost per passenger.

Comment: Given that fuel used per passenger decreases as a result of increased passenger capacity, and assuming that many other operating costs (pilot's wages, maintenance, etc.) remain fixed, it follows that increased passenger capacity results in lower operating costs per passenger.

5. Assertion: Increased passenger capacity would result in

lower fares.

Comment: In consideration of the competitive nature of the air taxi industry, it is reasonable to assume that a decrease in operating costs per passenger would be reflected

in lower fares.

6. Assertion: Increased passenger capacity would help to

conserve the environment.Comment: Assuming that the amount of harmful emissions generated by a given airplane are directly proportional to

the amount of fuel burned, this assertion follows from the argument regarding the amount of fuel burned per passenger.

Aero Twin provides the following additional arguments.

The original petition, as submitted, supported the assertion that safety would be unaffected by stressing the fact that the airplane would be virtually unchanged. The net effect of carrying four additional passengers would be that four additional passengers would be subject to the same levels of risk that are acceptable to the FAA when nine passengers are on board. This argument addresses the question of how many passengers are permitted to be exposed to the risk of flight in a normal category, single-engine airplane.

The modification of the Cessna 208B would include a restriction on flight into instrument meteorological conditions (IMC). This restriction was included specifically to provide a margin of safety over and above the requirements of Parts 23 and 135 and greatly reduce the risk of a serious accident occurring as a result of an engine failure.

The accident record of small multiengine airplanes that experience engine failure in flight shows that having a second engine on board does not guarantee continued safe flight and landing. National Transportation Safety Board (NTSB) report (NTSB-AAS-79-2) has shown that statistics favor the survivability of an engine failure crash in a single-engine airplane.

The Pratt and Whitney PT6 series engines are among the most reliable powerplants on record. The PT6A-114A is one of the recent additions to this series. Although statistical data have not been provided to support or quantify this statement, the fact

that the modern PT6 is more reliable than its older, lower-powered reciprocating counterparts is beyond dispute. The Cessna 208B is a new airplane that typically does not have the problems associated with the existing aging airplane fleet, including both single-engine and twin-engine airplanes.

The denial of petition for Exemption No. 5299 cited the higher levels of safety required by Part 23 for airplanes certificated to carry more than nine passengers. It is assumed that this refers to Special Federal Aviation Regulations (SFAR) 23 because Section 23.561 does not impose higher standards of safety on commuter category airplanes. Regarding doors and exits specifically, the Cessna 208B meets the requirements of Part 23, SFAR 23.32, except for paragraph (e), which addresses exit markings. This requirement could be met as an added condition of exemption.

The FAR are structured such that there exists a stepwise increase in the permitted number of passengers corresponding to increasedstandards of certification. Yet the specific regulations from which exemption is being sought in this petition fail to differentiate between the new 675 hp Cessna 208B and the old 300 hp reciprocating Cessna 207. A large margin of safety does exist, and this margin is greatly increased by a restriction on flight into IMC.

Aero Twin summarizes its statements, comments, and arguments by stating that carrying four additional passengers does not compromise the existing level of safety and that the restriction on flight into IMC greatly enhances the existing level of safety. Furthermore, the existing level of safety met by the Cessna 208B is significantly higher than the minimum required by Part 23 for certification in the normal category.

On July 29, 1991, Aero Twin requested to amend its Petition for Reconsideration by including the proposed condition that the subject airplane, when equipped with 3 additional passenger seats and operated under Part 135, will have a second-in-command on board; therefore, maximum passenger occupancy would be 12. This condition would bring the proposed operation into compliance with Section 135.99(b) and provide a greater margin of safety. In addition to this, on September 23, 1991, Aero Twin submitted a copy of Cessna's 14-place seating supplement to the Cessna 208B pilot operating handbook, to be placed into the file containing the petition for reconsideration.

The FAA's analysis/summary is as follows:

Section 11.55 of the FAR states that a petition for reconsideration must be based on one or more of the following factors: (1) a finding of material fact that is erroneous; (2) a necessary legal conclusion that is without governing precedent or is a departure from or contrary to law, FAA rules, or precedent;

or (3) an additional fact relevant to the decision that was not presented in the initial petition for exemption and the reason for the failure to include that fact in the original petition.

Aero Twin has based this petition for reconsideration on additional information that it did not include originally because it did not understand the level of substantiation required to support the petition. The FAA has re-analyzed Aero Twin's original petition and the additional information presented in its petition for reconsideration. In addition, the FAA has reviewed an amendment to the petition for reconsideration made by the petitioner by letter dated July 29, 1991, and additional information provided by the petitioner on September 23, 1991.

Although additional information has been submitted with this petition for reconsideration, Aero Twin has not established how it would provide a level of safety equivalent to that provided by the applicable regulations from which the exemption is sought. Further, Aero Twin has failed to offer any reason why it is unique from the general class of similarly situated operators whoare subject to the same regulations.

For many years, the FAA has required the increased level of safety that is associated with two pilots and two or more engines for commercial flights in airplanes capable of carrying more than nine passengers. This rule existed before the Cessna 208B was type certificated. The Federal Aviation Act of 1958, as amended, charges the FAA with the duty of promoting safety of flight of civil aircraft and empowers the FAA to prescribe minimum standards in the interest of safety. In prescribing these

standards, the FAA must make classifications in order to maintain an appropriate level of safety for operations with varying levels of complexity and varying degrees of risk to the public. The nine-passenger limit was established by the FAA for normal category airplanes. This limit was the result of a considered decision to provide a higher level of safety for airplanes carrying more than nine people in air taxi or commercial service.

Aero Twin states that by restricting flight into IMC a greater margin of safety will be achieved. The FAA disagrees. Whether the Cessna 208B is flying under IFR or VFR, continued safe flight after the loss of an engine is not possible. Since continued safe flight after loss of an engine is possible for the larger multiengine airplanes that meet the one engine inoperative requirement of Part 135, Appendix A, Aero Twin has not shown that its proposed action would provide a level of safety equal to that provided by the rule from which it seeks exemption.

Aero Twin raises the argument that NTSB report NTSB-AAS-79-2 favors the survivability of an engine-failure crash in a single-engine rather than a multiengine airplane; therefore, having a second engine on board does not guarantee continued safe flight and landing. These statements are independent of one another and do not support a conclusion that single-engine airplanes are safer than multiengine airplanes. Survivability following a crash is a function of many variables, some of which are structural crashworthiness, pilot skill, impact speed, weather, terrain, occupant seat restraint systems, surface conditions at impact site, etc. To deduce that having a second engine on board decreases the chance of survival on a commuter category airplane after an engine failure is incorrect. As stated in the previous denial of exemption, the commuter category airplane performance requirements were developed, in part, to provide continued airworthiness ability after the failure of an engine.

Aero Twin argues that the Pratt and Whitney PT6 series engines are among the most reliable powerplants on record, and that they have a much greater reliability than reciprocating engines; therefore, the single-engine turbopropeller powered Cessna 208B should be allowed to carry more than nine passengers. The FAA does not question the reliability of the PT6 series engines. A question similar to this regarding the reliability of single-engine turbopropeller airplanes was presented to the FAAprior to the adoption of Amendment 23-34, which adopted the commuter category airplane regulations into Part 23. In the event of an in-flight engine failure, a single-engine airplane does not provide the level of safety expected from a commuter category airplane, which must have the capability for continued safe flight and landing after probable failures, including the failure of an engine.

Aero Twin assumes that the FAA was referring to SFAR 23 in the denial of Exemption No. 5299 when it cited the higher levels of safety required of Part 23, airplanes certificated to carry more than nine passengers. In support of its assumption, Aero Twin states that Section 23.561 does not impose higher standards of safety on commuter category airplanes. While this latter statement is true, Aero Twin's assumption is incorrect. Amendment 23-34, which added the commuter category to Part 23 adopted over 50 different regulations, all of which were and are unique for that category of airplane. These regulations were established to provide a higher level of safety for the larger (maximum of 19 passenger seats) commuter category airplanes than was previously required for the smaller Part 23 airplanes used in air transportation.

Aero Twin adds that the Cessna 208B meets the door and exit requirements of SFAR 23.32, except for those set forth in paragraph (e), which addresses exit markings. Aero Twin further states that exit markings could be added as a condition of exemption if required. SFAR 23, however, does not apply to Aero Twin's situation. SFAR 23 was originally developed to certificate normal category, multiengine reciprocating and turbopropeller-powered airplanes that could carry more than 10 occupants and that were intended for use in operations under Part

135. Furthermore, under the additional airworthiness requirements of Section 135.169(b)(3), type certification under SFAR 23 is not available to airplanes type certificated after

July 19, 1970.

Aero Twin next argues that the specific regulations from which it seeks exemption fail to differentiate between the new 675 hp Cessna 208B and the old 300 hp reciprocating Cessna 207. The FAA agrees that a margin of safety exists between the Cessna 207 and the Cessna 208B. This difference is due in part to the respective dates on which they applied for type certification. In this case, 22 amendments were added to Part 23 during the 14 years that elapsed between the two different certification dates.

Aero Twin had asserted in its July 29, 1991, amendment to its petition for reconsideration that a greater margin of safety would be provided by its newly-proposed condition to require a second-in-command on board the airplane whenever it is equipped with three additional passenger seats and operated under Part 135, in compliance with Section 135.99(b). This statement is partially true in that a greater margin of safety would be achieved than would otherwise be achieved by a single-pilotCessna 208B certificated in the normal category. However, the provisions of this regulation must currently be met by all air taxi and commercial operators with respect to any of their aircraft that has a passenger seating configuration, excluding any pilot seat, of ten seats or more.

In addition, while Part 135, Appendix A, does not set forth additional airworthiness requirements applicable to ten or more passenger airplanes, its provisions are applicable only to Part 135 operators, and no exemption from these standards could be granted to a non-operator, such as Aero Twin.

In consideration of the foregoing, and based on the findings in the denial of the petition in Exemption No. 5299 and analysis of the material submitted with the petition for reconsideration, I find that a grant of the petition for exemption would not provide an equivalent level of safety to that provided by the applicable Federal Aviation Regulations and would not be in the public interest. Therefore, pursuant to the authority contained in

Sections 313(a) and 601(c) of the Federal Aviation Act of 1958, as amended, the petition for reconsideration and the petition for exemption from Section 23.3(a) and the one-engine inoperative requirements of Part 135, Appendix A, of the Federal Aviation Regulations are hereby denied.

Issued in Washington, on May 8, 1992.

/s/ Barry Lambert Harris Acting AdministratorExemption No. 5299

UNITED STATES OF AMERICA

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

KANSAS CITY, MISSOURI 64106

****************************************

* In the matter of the petition of *

*

AERO TWIN, INC. * * Regulatory Docket for an exemption from Sections 23.3(a) * No. 090CE and Part 135, Appendix A, * of the Federal Aviation Regulations *

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DENIAL OF EXEMPTION

By letter dated December 26, 1990, Mr. John Kuest, Aerospace Engineer, Aero Twin, Inc., 2404 Merrill Field Drive, Anchorage, Alaska 99501, petitioned for an exemption from compliance with Section 23.3(a) and Part 135, Appendix A, of the Federal Aviation Regulations (FAR) to permit the modification of the single-engine Cessna Model 208B from a nine passenger to a thirteen passenger airplane by the use of Cessna Modification Kit No. CS8-014.

The Petitioner requires relief from the following regulations:

Section 23.3(a) requires, in part, that an airplane type certificated to the normal category will be limited to a seating configuration of nine or less, excluding pilots seats. Part 135, Appendix A, states the one-engine inoperative requirements for Air Taxi and Commercial Operators operating an airplane with 10 or more passenger

seats.

The Petitioner's supports its request with the following

information:

The petitioner contends that by granting an exemption, the public interest will be served. The increase in the number of seats, as allowed in numerous foreign countries, permits the aircraft to be operated at a significantly lower cost per passenger. This lowers passenger expenses, thus decreasing fares. The increased passenger capacity decreases the number of aircraft or flights required to service a given number of passengers. Therefore, it lowers net fuel consumption, conserves the environment, and

decreases air traffic controller workload.The petitioner further states the following reasons why the exemption would not adversely affect safety or that action taken would provide the level of safety equal to that provided by the rule from which the exemption is sought.

a. "This change does not effect the center of gravity range of the aircraft."

b. "This change will not be approved for flight into

IFR conditions."

c. "This change does not increase or alter the certified takeoff weight of the aircraft."

d. "This change does not alter anything relating to the propulsive or propeller system."

e. "This change does not require airframe

modification."

f. "The change uses Cessna Aircraft Corporation

manufactured FAA certified seats, identical to the Cessna installation which is already in use in foreign

countries."

Comments on published petition summary:

A summary of this petition was published in the FEDERAL REGISTER for public comment on February 6, 1991 (56 FR 4895). The comment period closed February 26, 1991. No

comments were received.

The Federal Aviation Administration's (FAA) analysis is as

follows:

To obtain the exemption, the petitioner must show, as required by Section 11.25(b)(5), that: (1) granting the request is in the public interest, and (2) the exemption

would not adversely affect safety, or that a level of safety will be provided that is equal to that provided by the rule from which the exemption is sought.

The petitioner claims that public interest will be served if the exemption is granted and yet little supportive evidence or technical data has been submitted to support this claim. The contention is that, by increasing the number of passenger seats from 9 to 13, it will significantly lower costs per passenger, passenger expenses

and fares. This will decrease: the number of aircraft or flights required to service a given number of passengers, net fuel consumption, and air traffic controller workload

and, therefore, conserve the environment. These claims are not supported by the data furnished in the request for exemption.The petitioner further contends that safety will not be adversely affected and supports this claim by stating that the airplanes C.G. range, certificated gross take-off weight, airframe, and propulsive system will remain unchanged after the modification. The FAA considers these conditions as being unique to the certification of the airplane in the normal category. The petitioner, however, does not show a level of safety will be provided equal to that of the applicable sections of the FAR. The existing Part 23 regulations require higher levels of safety, in terms of crashworthiness, number of exits, exit markings, etc., for airplanes certificated to carry more than 9

passengers.

The petitioner further requests relief from the one-engine inoperative requirements of Part 135, Appendix A, to the extent of becoming one-engine operative requirements, for the petitioners particular application. The petitioner, however, fails to offer any reason or argument why the petitioner is unique from the same general class of operator who is also subject to the same regulations.

In 1966, the FAA established an air taxi airworthiness program with the objective to provide a transition for air taxi airplanes from the small airplane requirements of Part 23 to the transport category airplane requirements of Part 25. That program resulted in the issuance of Special Federal Aviation Regulation No. 23 (34 FR 189, January 7, 1969). An additional step in the upgrading of airworthiness standards for reciprocating-engine and turbopropeller- powered small airplanes used in Part 135 operations was the adoption of Appendix A to Part 135 (35 FR 10098, July 19,

1970), which set forth additional airworthiness standards for airplanes with 10 seats or more.

In developing the additional performance requirements of Appendix A, the FAA drew upon the experience gained in the development of the airworthiness standards for transport category airplanes and the many years of operation of such airplanes. As sufficient exposure was accumulated with the affected airplanes, the need for a higher performance level for takeoff and landing would be demonstrated, as it was for transport category airplanes. In developing this rule, the FAA also considered the operating experience of certificated air taxi airplanes at that time. A review of the accident record with small multiengine air taxi airplanes revealed that there were 13 accidents in the 5 year period from the beginning of 1964 through the end of 1968 in which engine failures occurred in flight during takeoff. There were 6 injuries and 32 fatalities in those 13 accidents. During that same period, there were no accidents in transport category airplanes in air carrier operations in which engine failure occurred in flight during takeoff. The FAA, therefore, believed that the safety record of the transportcategory airplanes was due, to a large extent, to airplane performance requirements that provided continued airworthiness ability after the failure of an engine.

On July 7, 1970, the FAA issued Notice No. 70-25 (35 FR 10911) proposing to upgrade the level of airworthiness of small airplanes intended for operations under Part 135. In response

to the comments received to the notice and after further

consideration, the FAA determined to limit the future applicability of Part 23 to small normal, utility, and acrobatic category airplanes with a seating configuration (excluding pilot

seats) of 9 or less. This action was based on a trend toward an increase in the number and types of airplanes designed to carry relatively large numbers of passengers. At that time, the FAA considered that continued applicability of Part 23 to small airplanes designed to carry 10 or more passengers was no longer in the interest of safety. Thus, Amendment 23-10, which limited the number of seats (excluding pilots' seats) to 9 or less, became effective March 13, 1971, and was applicable to normal, utility, and acrobatic category airplanes.

On November 15, 1983, the FAA issued Notice No. 83-17 (48 FR 52010). This notice proposed to amend, in part, the regulations of Part 23 to adopt certification procedures and airworthiness regulations for an additional category of airplane designated as the Commuter Category. It was at this time that the current Section 23.3 was proposed, along with the introduction of a class of airplanes having a maximum certificated takeoff weight of 19,000 lbs. or less and having a seating capacity of up to and including 19 seats (excluding pilots' seats).

At this time, it was recommended that Section 23.3(d) be changed to add single-engine, turbopropeller-powered airplanes to the commuter category, the contention being that turbopropeller-engines have a record of increased reliability over reciprocating engines. The FAA did not agree with this recommendation because the prospect of a single-engine failure does not provide the level of safety expected from the airworthiness standards for commuter category airplanes, which must have the ability for continued safe flight and landing after probable failures, including the failure of an engine. Notice No. 83-17 was

adopted by Amendment 23-34 on January 8, 1987.

In consideration of the foregoing, I find that a grant of exemption, as requested, is not in the public interest nor maintains the level of safety required by the rule from which the exemption is sought. Therefore, pursuant to the authority

of Sections 313(a) and 601(c) of the Federal Aviation Act of 1958, as amended, delegated to me by the Administrator (14 CFR 11.53), the petition of Aero Twin, Inc. for an exemption from Section 23.3(a) and the one-engine inoperative requirements of Part 135, Appendix A, of the Federal Aviation Regulations ishereby denied.

Issued in Kansas City, Missouri on April 16, 1991.

/s Don C. Jacobsen Acting Manager Small Airplane DirectorateExemption No. 6715

UNITED STATES OF AMERICA

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

KANSAS CITY, MISSOURI 64106

* * * * * * * * * * * * * * * * * * *

* In the matter of the petition of *

* AIR TRACTOR, INC. * Regulatory Docket

* No. 137CE for exemption from Section 23.3(a) *

of Title 14 of the * Code of Federal Regulations (CFR) *

*

* * * * * * * * * * * * * * * * * * *

DENIAL OF EXEMPTION

By letters dated November 27, December 14, December 21, and December 27, 1996, and April 14, 1997, Mr. Leland Snow, Air Tractor Inc., Post Office Box 485, Olney, Texas 76374, petitioned for an exemption from compliance with Section 23.3(a) of Title 14, Code of Federal Regulations (14 CFR) to permit the Air Tractor 10 (AT-10), a normal category airplane, to exceed the 12,500 pound limitation for this category of airplane.

The petitioner requires relief from the following regulations:

Section 23.3(a) requires, in part, that an airplane type certificated to the normal category will have a maximum certificated gross weight of less than 12,500 pounds.

The petitioner supports the request with the following

information:

By letter dated November 27, 1996, Air Tractor Inc., announced plans to develop a line of freight-carrying airplanes. The first model proposed will be the AT-10. This model will be powered by two Pratt & Whitney PT6A-65B engines driving a single propeller by means of a Soloy- designed gearbox. Since the AT-10 will be designed as purely a freight-carrying airplane, there will not be any passenger windows or seats except for two crew and the possibility of a jump seat for a loading supervisor. The gross weight of the airplane is envisioned to be near 22,000

pounds.

On December 14, 1996, Air Tractor Inc. amended their initial proposal by substituting the two PT6A-65B turboprop engines with a combined Soloy gearbox with a single Pratt and Whitney 100 series turboprop engine.By letter dated December 21, 1996, Air Tractor Inc. redesigned the airplane to have a more conventional fuselage, and the single Pratt and Whitney PW123 was selected as the powerplant for the airplane.

Further design changes were noted by letter dated April 14, 1997, which included the following: a reduction in engine size from a Pratt and Whitney PW123 to a PW121, widening of the main landing gear track, enlargement of the vertical tail and a revised aileron and flap design.

The petitioner envisions the AT-10 as an airplane as easy to fly as a primary trainer, with low landing speed, good visibility from the cockpit, a wing with forgiving stall characteristics, and fixed landing gear.

The petitioner states that it would be in the public interest for the FAA to grant this exemption because it would benefit business to have low cost, next day delivery of critically needed parts or documents. Inflation drives up the cost of doing business and many companies turn to larger equipment as a means of offsetting rising costs. The AT-10 would meet this challenge by being able to carry containerized freight and by being flown by one pilot instead of the two that are currently being used in airplanes of similar service, like the Fairchild F27.

In addition, the petitioner believes that the AT-10 would feature a new fuel-efficient engine with lower maintenance and overhaul costs. A large fleet of AT-10s carrying priority freight would result in a continuation of present economical next day delivery of packages and letters for the public. Manufacturing a large number of AT-10s would create many jobs and greatly benefit small communities where the

work would be carried out.

The petitioner refers to a previous exemption that was granted to certificate the Air Tractor 802 (AT-802) at a gross weight of 16,000 pounds in the normal category as an example of how the public has benefited greatly from the FAA's decision to allow a single-engine airplane to be certificated above the 12,500 pound gross weight limit.

The petitioner then states that the weight limits that were set in Section 23.3 were done so as a means of measuring the complexity of a new design. Usually, the heavier an airplane is the more complex it is and the more need there is for additional pilot training or for more pilots to operate the airplane. The AT-802 proved that size and complexity do not necessarily go together. Furthermore, Air Tractor was able to petition successfully to waive the requirement for a type rating for AT-802 pilots based on the FAA's finding that the AT-802, while large, had docilehandling characteristics and was as easy to land as any of

the smaller Air Tractors.

Comments on published petition summary:

A summary of this petition was published in the FEDERAL REGISTER for public comment on February 19, 1997 (62 FR 7492). Initially, the comment period was to close on March 11, 1997, but at the request of commenters it was extended to April 11, 1997. The FAA received responses from twenty different commenters. All of the commenters were in favor of the exemption.

Seven commenters described the economic benefits of operating a single-engine airplane instead of a multiengine airplane. The FAA agrees with the hypothetical argument, but a more realistic argument would be based on a comparison of operating costs with other cargo-carrying airplanes that are close to the gross weight of the AT-10. This type of data was not included in any of the comments received.

Nine commenters argued that the reliability of modern single-engine turboprop powerplants is better than that of single or multiengine piston powerplants that are currently being used in the commercial fleet. The FAA disagrees. The commercial fleet does not contain any normal category single-engine piston airplanes that have a gross weight

greater than 12,500 pounds. Furthermore, the commenters have not presented any data to substantiate their claim. Based on information presented to the FAA by the petitioner, the accident rate per 100,000 hours due to power loss (Based on Commercial and Air Carrier Operations Data) is slightly lower for multiengine piston-powered airplanes than for single-engine turboprop-powered airplanes. In addition, when comparing the accident rate per 100,000 hours of a single-engine turboprop airplane to a multiengine turboprop airplane, the accident rate for a multiengine turboprop airplane per 100,000 hours is significantly less than a single-engine turboprop airplane.

Five commenters state that the 12,500 pound limit, which was set more than 30 years ago, is based on a false assumption that heavier airplanes are automatically more complex and would, therefore, require different certification rules. Airplanes have, in fact, become larger without becoming more complex; thus, lending doubt to the criterion upon which the limit has been based in the past.

The FAA disagrees. For many years, the FAA has required an increased level of safety that is associated with two pilots and two or more engines for commercial flights carrying more than nine passengers or exceeding 12,500 pounds. The Federal Aviation Act charges the FAA with the duty of promoting safety of flight of civil aircraft and empowersthe FAA to prescribe minimum standards as may be required in the interest of safety. In prescribing these standards, the

FAA must make classifications of such standards as appropriate to maintain an equivalent level of safety for operations with varying levels of complexity and varying degrees of risk to the public. The nine passenger, 12,500 pound gross weight limit was established by the FAA for normal category airplanes. At the time that the 12,500 pounds weight limitation on small airplanes was established in 1953, civil airplanes were well below or well above that weight. This limit was the result of a decision to provide a higher level of safety for airplanes carrying more than nine passengers or exceeding 12,500 pounds gross weight.

Six commenters cite the precedent set by the FAA in granting an exemption for the single-engine AT-802 to be certificated at 16,000 pounds gross weight as a reason to grant the petition for the AT-10. The FAA disagrees. The reasons for granting the exemption for the AT-802 are not applicable to the AT-10. The AT-802 is a restricted category, agricultural/firefighting airplane. Unlike the AT-10, which is proposed to be a normal category airplane, the AT-802 is used only for special purpose operations over sparsely populated isolated areas.

Four commenters state that if the certification rules of 14 CFR Part 25 were used for the AT-10, the airplane would be required to have multiple engines, and the costs involved would make the price of the airplane operation and maintenance costs too prohibitive. The FAA agrees production, operation, and maintenance costs would be higher for a twin engine airplane as compared to a single-engine airplane at the same gross weight, as would the final cost to the consumer. However, a number of airplanes that are used in cargo operation, in the range of 12,500 to 60,000 pounds gross weight, have been certificated to higher levels of safety than the Part 23 normal category. If cost savings were the only criterion for the FAA to grant this exemption, it would do so. However, the FAA's highest priority is to provide for aviation safety. Certification standards for any Part 23 airplane above 12,500 pounds gross weight require multiengine designs that offer continued safe flight capability in the event of engine failure. This requirement not only gives more protection to the traveling public in the air, but also to people on the ground.

Fourteen commenters believe the benefits of the AT-10 to the American Public to be immense, by providing a larger, economical airplane that has lower operational costs and better fuel economy. The FAA agrees that the public does benefit when lower operational costs and better fuel economy

costs result in lower costs to the customer. However, this

type of data for the AT-10 has not been presented to the FAA, and the AT-10 needs to be compared with the fleet ofairplanes it will compete against. If this statement is to be acceptable, the data needs to be normalized to show the cost involved with shipping a standard weight increment, whether it is one pound or one thousand pounds.

One commenter states that Federal Express has, likewise, demonstrated with their Caravan Fleet that the single pilot, turbine powered, single-engine airplanes can safely and efficiently move freight. The FAA agrees. The Cessna Caravan is a good example of a Part 23, normal category airplane that efficiently moves freight and transports people, and is able to do so even though its gross weight is limited to less than 12,500 pounds.

One commenter states that, from experience, it is much safer to fly a single-engine turbopropeller Air Tractor than a twin engine reciprocating airplane. Another commenter states that all turboprop Air Tractors have the same handling characteristics regardless of size and that it would be logical to expect the 22,000 pound AT-10 to have the same handling characteristics as one with a 12,500 pound gross weight. Since the AT-10 has not yet been certificated and Air Tractor has never type certificated an airplane out of the restricted category, the FAA assumes the commenters are addressing special purpose, restricted category Air Tractor airplanes and their handling characteristics. Neither of these comments are the subject of this exemption.

Two commenters state that military aviation is not encumbered by category limits based on airplane gross weight. Also, the 12,500 pound limit of Part 23 for normal category airplanes is archaic and is not in step with the strides of the equipment manufacturers and the capabilities of the airplane industry. Their solution is to establish a new category, cargo airplane, in Part 23 with a gross weight to be established in concert with industry. Until then, it is not reasonable to require a cargo-only airplane to go through the certification process of Part 25, which is written with the assumption that the airplane will be carrying people.

The FAA agrees. Military airplanes are not encumbered by category limits based on gross weight, but they are designed to different standards and, unless they are surplussed and are shown to comply with Section 21.27, they do not receive FAA type certificates. The FAA also agrees that the 12,500 pound limit is a well-established regulation. This limit

can be considered a demarcation with a well-documented history of safety. In the interest of safety, any demarcation is independent of the state of technology, which is constantly changing, and must exist whether the demarcation is established at 12,500 pounds or some other limit. Since the commenters do not present the FAA with any data or documented proof that a more beneficial weight limitexists, the present limit will remain. Therefore, until the FAA has sufficient reason to change the gross weight limit for normal category airplanes, or regulations are adopted for the type certification of airplanes specifically designed to carry cargo, airplanes designed with gross weights in excess of 12,500 pounds will be required to comply with the commuter category regulations of Part 23 or the transport category regulations of Part 25.

The Small Aircraft Manufacturers Association (SAMA) states that the Federal Aviation Act provides support for distinguishing between all-cargo operations and passenger- carrying operations and for encouraging all cargo operations. The Act contains a specific policy section regarding All Cargo Air Transportation Considerations that establishes the policy of encouraging and developing an expedited all-cargo air transportation system responsive to the present and future needs of shippers. The Act also defines and distinguishes between air carriers, which provide air transportation as a common carrier, and air commerce for the operation of aircraft in furthering a

business.

The FAA agrees that the Federal Aviation Act makes these provisions. The Act also assigns and maintains safety as the highest priority in air commerce. Before authorizing new air transportation services, the FAA evaluates the safety implications of those services and prevents deterioration of established safety procedures. The Act recognizes the clear intent, encouragement, and dedication of Congress both to further the highest degree of safety in air transportation and air commerce and to maintain the safety vigilance that has evolved in air transportation and

air commerce.

It is a longstanding requirement that airplanes in excess of 12,500 pounds must have one engine inoperative climb performance, which has been provided by multiengine installations. This requirement reduces the risk of exposure to a forced landing. A single-engine airplane that has an engine shutdown will be making a forced landing. The forced landing of an aircraft in excess of 12,500 pounds is considered very hazardous and exposes the public to a higher risk than the forced landing of a small airplane because of the increased mass, greater volume of fuel, and greater kinetic energy. The public now expects this degree of safety. In this respect, the FAA has no assurance that the AT-10 can be safely certificated at 22,000 pounds gross weight with a single-engine using the normal category certification requirements of Part 23.

SAMA further states that there is a precedent in Part 23 for

a different certification treatment within Part 23 normal category for airplanes limited to all-cargo operations onlyby design and use. Before Part 23, airplane airworthiness standards distinguished between cargo-only and passenger- carrying airplanes. Aeronautics Bulletin No. 7-A had different performance requirements for airplanes neither designed nor used to carry passengers. In CAR 4a, a

distinction was made between air carrier and non-air carrier airplanes regarding required equipment.

The FAA agrees. Prior to recodification, a distinction was present between passenger and cargo-carrying airplanes. Upon recodification, this distinction was dropped in favor of a set of regulations that were inclusive of both designs. The normal category, thereby, inherently contains a certification treatment for airplanes designed to carry cargo, up to a limit of 12,500 pounds gross weight.

SAMA states that Part 25 is intended to provide airworthiness standards for the largest transport category airplane carrying hundreds of passengers. It contains many requirements that are not necessary for the appropriate level of safety certitude for a 22,000 pound all-cargo airplane. Compliance with these requirements would impose a substantial cost burden on the airplane yet provide no commensurate safety benefit. Compliance would, therefore, be against the Federal Aviation Act policy of encouraging and developing an expedited all-cargo air transportation system. Numerous exceptions from the requirements of Part 25 would be appropriate for the AT-10 and would be required to avoid an unnecessary burden on the airplane.

The FAA disagrees. Part 25 is intended to provide airworthiness standards for a full range of airplanes that are designed for varied commercial and private use. These

standards are the same for part 25 cargo and passenger airplanes with the exception of passenger cabin safety regulations. Regulation of the operation of these airplanes is covered in other CFR subchapters, which are dependent upon the service the airplane is providing. Since recodification, all civil airplanes with gross weights above 12,500 pounds, independent of the criteria to which they were designed, were certified to a higher level of safety than that required of Part 23 normal category airplanes. The gross weight limit of 12,500 pounds, and not 22,000 pounds, was set at a time when there were very few airplanes built close to the 12,500 pound gross weight limit. The FAA did not envision certification standards for single-engine normal category airplanes with gross weights in excess of 12,500 pounds at the time the limit was set.

In 1977, the FAA/Industry Commuter Aircraft Weight Review Committee submitted a petition to amend the regulations to allow certain small airplanes to be type certificated at maximum certificated takeoff weights greater than the 12,500 pound limitation without complying with the requirements ofPart 25. Responding to the petition, the FAA initiated a three-phase program. The first phase was the issuance of revised Part 135, which aligned the rules for those operations more closely with those of Part 121.

The second phase was initiated by issuance of Notice No. 78-14, which proposed temporary rules for additional airworthiness requirements to provide for increased takeoff gross weight and passenger seating capacity of certain existing small propeller driven multiengine airplanes. The outcome of this notice was the adoption of Special Federal Aviation Regulation (SFAR) No. 41. SFAR No. 41 was designed to fill the gap between Part 23 and Part 25 certification standards until airplanes could be developed and certificated under the proposed Part 24.

The third phase was the establishment of the Light Transport Airplane Airworthiness Review, which resulted in proposed Title 14 CFR, Part 24 for multiengine airplanes with a maximum gross weight up to 35,000 pounds and a seating capacity up to 30 passengers. The Part 24 project was

terminated because the economic benefits at that time for a new lightweight transport airplane airworthiness regulation

could not be realized.

Regarding the comment made that the requirements of Part 25 would impose a substantial cost burden and yet provide little commensurate safety benefit, the FAA has not received any data to support this statement. The subject of this exemption is not whether numerous exceptions to the requirements of Part 25 would be appropriate and would be required to avoid an unnecessary burden on the airplane design.

SAMA comments that the proposal is consistent with policy established by the FAA's Small Airplane Compliance Program. This program identified a segment of Part 23 airplanes that could be certificated using methods of compliance that were lower cost than Part 23 generally could be interpreted to require because of the non-complex systems and non-demanding speed and altitude environment of the airplane in the program and their limitations on seats to no more than four. The same principle should apply to the AT-10.

The FAA disagrees. The applicability of the Small Airplane Compliance Program is intended for airplanes that had gross weights less than 12,500 pounds. The AT-10 has a gross weight almost twice that amount. In addition, the program's benefits were meant to apply to many manufacturers unlike this petition for exemption.

SAMA adds that the proposal is consistent with the Challenge

2000 recommendations under which the FAA would reexamine its certification system and consider both operational andairplane certification requirements when establishing the correct level of certitude for an airplane design. This level would be determined according to the hierarchy of customers based on their expectations of safety oversight by the FAA, which, in turn, is based on their degree of control of the airplane's operation. Using this approach, SAMA states that when an airplane is limited by design and use to all cargo operations, the level of regulatory oversight appropriate to the airplane is that of a Part 23 airplane not a Part 25 airplane.

The FAA disagrees. The Challenge 2000 recommendations were the result of an initiative to review and improve current processes, and to identify redundant and low-value practices as well as those safety regulatory functions that could be significantly enhanced by organizational change. Aviation safety must be held at existing or improved levels while Challenge 2000 changes are being implemented over a period of several years. The recommendations that resulted from

the initiative are as follows:

1. Shift roles and responsibilities of the Office of Certification and Regulation (AVR) and industry.

2. Deploy functional resources through centers of

excellence.

3. Empower rulemaking and evolve to performance based regulations.

4. Resize and restructure AVR for the new mission and operating model.

The integration of the roles of certification and operation

are included in the recommendations and will have some regulatory impact in the future. However, at this point in time, the FAA does not agree that the regulations of the Part 23 normal category would be the appropriate certification basis for an airplane with a gross weight of 22,000 pounds designed for cargo operations.

One commenter states that the Air Tractor AT-10 is not more complex than a lighter single-engine airplane and is intended for freight operations. Also, the commenter believes that the reduced complexity of this single-engine airplane, when compared to similar multiengine airplanes, gives a safer, more reliable vehicle for transport of priority freight.

The FAA can only assume that the comment made is accurate. However, the issue of complexity has little bearing on continued safe flight after an engine failure for all airplanes with gross weights exceeding 12,500 pounds. This limit has provided safety not only for the traveling publicbut also for the public on the ground. In addition, the complexity of an airplane is not the reason the FAA chose the existing 12,500 pound gross weight limit for normal category airplanes.

One commenter states that a single-engine airplane like the AT-10 will have a smaller impact on the environment than a multiengine airplane. The FAA agrees. If a comparison is made between two airplanes at the same gross weight, the single-engine airplane will most likely have the smaller impact on the environment. However, a more realistic approach would be to compare, on a normalized basis, the environmental impact of the AT-10 with an airplane it would replace in the existing fleet.

Two commenters use the example of the Boeing 777 compared to the Boeing 747 as one in which increased safety or greater payload does not always mean more engines. The FAA disagrees. In the example given, both the 777 and the 747 have the same level of safety. In the event of an engine failure, both airplanes are capable of continued safe flight. The FAA agrees with the second part of the statement; a greater payload does not always require more engines.

The Federal Aviation Administration's (FAA) analysis is as

follows:

To obtain the exemption, the petitioner must show, as required by Section 11.25(b)(5), that: (1) granting the request is in the public interest, and (2) the exemption

would not adversely affect safety, or that a level of safety will be provided that is equal to that provided by the rule from which the exemption is sought.

In a review of the FAA's exemption files, a similar petition was found that closely parallels this petition. On September 19, 1979, the FAA denied a petition for exemption from Hawk Industries, Inc., Exemption No. 2822. The petitioner requested the FAA to permit the certification of its single-engine GAF-Hawk #125 airplane, which had a maximum takeoff weight of 14,500 pounds under Part 23. The petitioner supported its request with the following: the GAF-Hawk #125 will be: (1) a single engine, turboprop, all-freight airplane with a useful load of 8,000 pounds, (2) the engine used will be a very reliable one having 25,000,000 flying hours documented, (3) the wing loading, a modern camber airfoil, and full-span flaps provide excellent short field capability, (4) the airplane will be more fuel efficient than any current twin or piston-powered aircraft and (5) the current rule appears arbitrary and obsolete. The petitioner also proposed to restrict the airplane use to freight only as a compensating safety factor for the increased takeoff weight.At the time of the denial, the FAA stated that the

additional features and characteristics of the GAF Hawk #125 by themselves did not prevent the potentially catastrophic results of a forced landing. Furthermore, the petitioner had not shown that a grant of the requested exemption would provide a level of safety equal to that provided by the rule from which the exemption was sought.

The FAA has carefully reviewed the information contained in the petitioner's request for exemption. The petitioner states that granting the petition would be in the public interest and supports the statement by providing the FAA with cost data for the operation of the AT-10 based upon single-engine or twin-engine turboprop design. The petitioner also says that the AT-10 would feature a new fuel efficient engine with lower maintenance and overhaul costs. The FAA agrees with the hypothetical analysis, but the comparison is not a realistic approach. The petitioner should have provided data to show a comparison of his design with other existing cargo-carrying twin turboprop or twin reciprocating engine airplanes operating at the same approximate gross weight of 22,000 pounds. If this approach is not possible or the data is not available, normalized cost data based on the petitioner's design should be compared to other cargo-carrying airplanes operating in

commercial service.

The petitioner provides the FAA with a copy of the Robert E. Breiling Associates study "Powerplant Reliability Comparative Data" and then uses this data to show that a single-engine turboprop airplane is 1.46 times safer than a twin-engine piston-powered airplane. The FAA disagrees. The data the petitioner uses has not been normalized and is based on twin-engine piston-powered airplanes used in general aviation. The more representative data would be the data based on commercial and air carrier operations.

The petitioner refers to the previous exemption that was granted to certificate the model AT-802 at 16,000 pounds gross weight, in the normal category. The FAA disagrees. The AT-802 is certificated as a restricted category, special purpose agricultural/firefighting airplane, which complies with Section 21.25 of Part 21. All restricted category airplanes are required to meet the airworthiness requirements of an airplane category except those requirements that the Administrator finds inappropriate for the special purpose for which the airplane is to be used. In the case of the AT-802, appropriate normal category requirements of Part 23 were used for the certification basis of this airplane. However, this does not mean the AT-802 is a normal category airplane. Part 23 normal category airplanes are not restricted to areas of operation like the AT-802. The AT-802 is restricted, to be used onlyfor its intended special purpose operation in geographic areas that are isolated or sparsely populated.

The petitioner states the weight limits set in Section 23.3 were a means of measuring the complexity of new designs. Furthermore, the heavier an airplane is the more complex it is and the more need there is for additional pilot training or for more pilots to operate the airplane. The petitioner then states that the AT-802 proved that size and complexity do not go together. Air Tractor was able to petition successfully to waive the requirement for a type rating for AT-802 pilots based on the FAA's finding that the AT-802, while large, had docile handling characteristics.

The FAA disagrees. A similar question regarding weight and complexity was raised by some of the commenters. As stated previously, the FAA established the nine passenger, 12,500 pound gross weight limit for normal category airplanes. The FAA was aware that the limit provides a higher level of safety for airplanes carrying more than nine passengers or exceeding 12,500 pounds gross weight. This decision not only provides safety to the flying public but also to those people on the ground, which becomes more important as population density increases. Since the AT-10 will operate from different sized airports and over densely populated areas, and since the AT-10 does not have the capability for continued safe flight after an engine failure, this raises a safety risk to people on the ground. Furthermore, the case that the petitioner makes regarding the superior reliability of the turboprop engine that will be used for the AT-10 becomes a moot point since there is no FAR 23 regulation that requires an overall minimum reliability level for the engine installation and secondary owners/operators of the AT-10 could replace these engines with less reliable engines. In addition, the AT-802 is not a normal category airplane, it is a restricted category airplane that is used for agricultural/firefighting special purposes in geographical areas that are isolated or sparsely populated.

Although a great deal of information has been submitted with this petition for exemption the petitioner has not established how a level of safety would be provided equivalent to the applicable regulations from which an exemption is sought, and has failed to offer any reason why the petitioner is different from the same general class of operator who is also subject to the same regulations.

In consideration of the foregoing, and based on the analysis of the material submitted with the petition, I find that a grant of the petition for exemption would not provide an equivalent level of safety to that provided by the applicable Code of Federal Regulations and would not be in the public interest. Therefore, pursuant to the authority contained in 49 U.S.C. Sections 40113 and 44701, as amended, delegated to me by theAdministrator (14 CFR Section 11.53), the petition of Air Tractor, Inc., for exemption from 14 CFR Section 23.3(a) is hereby denied.

Issued in Kansas City, Missouri on December 31, 1997.

/s/ Michael Gallagher Manager, Small Airplane Directorate