Exemption No. 5451 

 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 Section 23.3(a) * No. 090CE 

 and Part 135, Appendix A, * 

 of the Federal Aviation Regulations * 

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

 

 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). Aero 

 
 

 Twin 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 increased 
 

 standards 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 who 

 
 

 are 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 FAA 

 
 

 prior 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-pilot 

 
 

 Cessna 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 Administrator 
 

 Exemption 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 * 

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

 

 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 transport 

 
 

 category 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 is 

 
 

 hereby denied. 

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

 /s Don C. Jacobsen 

 Acting Manager 

 Small Airplane Directorate 
 

 Exemption 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 docile 

 
 

 handling 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 empowers 

 
 

 the 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 of 

 
 

 airplanes 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 limit 

 
 

 exists, 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 only 
 

 by 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 of 

 
 

 Part 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 and 
 

 airplane 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 public 

 
 

 but 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 only 

 
 

 for 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 the 

 
 

 Administrator (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