Rules and Regulations. Final special conditions; request for comments

Agency: Federal Aviation Administration (FAA), DOT
Action: Final special conditions; request for comments
Citation: FR Doc. 2022-16558 · Docket No. FAA-2021-1193; Special Conditions No. 25-798-SC · 14 CFR 25

Summary

These special conditions are issued for the Dassault Aviation (Dassault) Model Falcon 6X Airplane. This airplane will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. This design feature is a high speed protection system that limits nose-down pilot authority at speeds above V ^C /M ^C . The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards.

Dates

This action is effective on Dassault on August 3, 2022. Send comments on or before September 19, 2022.

Supplementary Information

The substance of these special conditions has been published in the Federal Register for public comment in several prior instances with no substantive comments received. Therefore, the FAA finds, pursuant to § 11.38(b), that new comments are unlikely, and notice and comment prior to this publication are unnecessary. Comments Invited The FAA invites interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date for comments. The FAA may change these special conditions based on the comments received. Background On July 1, 2012, Dassault Aviation applied for a type certificate for its new Model Falcon 5X airplane. However, Dassault has decided not to release an airplane under the model designation Falcon 5X, instead choosing to change that model designation to Falcon 6X. In February of 2018, due to engine supplier issues, Dassault extended the type certificate application date for its Model Falcon 5X airplane under new Model Falcon 6X. This airplane is a twin-engine business jet with seating for 19 passengers and a maximum takeoff weight of 77,460 pounds. Type Certification Basis Under the provisions of title 14, Code of Federal Regulations (14 CFR) 21.17, Dassault must show that the Model Falcon 6X airplane meets the applicable provisions of part 25, as amended by amendments 25-1 through 25-146. If the Administrator finds that the applicable airworthiness regulations ( e.g., 14 CFR part 25) do not contain adequate or appropriate safety standards for the Dassault Model Falcon 6X airplane because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16. Special conditions are initially applicable to the model for which they are issued. Should the type certificate for that model be amended later to include any other model that incorporates the same novel or unusual design feature, these special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and special conditions, the Dassault Model Falcon 6X airplane must comply with the fuel-vent and exhaust-emission requirements of 14 CFR part 34, and the noise-certification requirements of 14 CFR part 36. The FAA issues special conditions, as defined in 14 CFR 11.19, in accordance with § 11.38, and they become part of the type certification basis under § 21.17(a)(2). Novel or Unusual Design Features The Dassault Model Falcon 6X airplane will incorporate the following novel or unusual design feature: The airplane is equipped with a high speed protection system that limits nose-down pilot authority at speeds above V ^C /M ^C , and prevents the airplane from actually performing the maneuver required under 14 CFR 25.335(b)(1). Discussion Section 25.335(b)(1) is an analytical envelope condition, adopted initially in part 4b of the Civil Air Regulations, to provide an acceptable speed margin between design cruise speed and design dive speed. The design dive speed impacts flutter clearance design speeds and airframe design loads. While the initial condition for the upset specified in the rule is 1g level flight, protection is afforded for other inadvertent overspeed conditions. Section 25.335(b)(1) is intended as a conservative enveloping condition for potential overspeed conditions, including non-symmetric ones. To establish that potential overspeed conditions are enveloped, the applicant should demonstrate that any reduced speed margin, based on the high speed protection system on the Dassault Model Falcon 6X, will not be exceeded in inadvertent, or gust induced, upsets resulting in initiation of the dive from non-symmetric attitudes; or that the flight-control laws protect the airplane from getting into non-symmetric upset conditions. The proposed special conditions identify various symmetric and non-symmetric maneuvers to ensure that an appropriate design dive speed, V ^D /M ^D , is established. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. Applicability As discussed above, these special conditions are applicable to the Dassault Model Falcon 6X airplane. Should Dassault apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, these special conditions would apply to that model as well. Conclusion This action affects only a certain novel or unusual design feature on one model of airplane. It is not a rule of general applicability. List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. Authority Citation The authority citation for these special conditions is as follows: Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 44704. The Special Conditions Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for Dassault Aviation Model Falcon 6X Airplane. Design Speed Definition (a) In lieu of compliance with 14 CFR 25.335(b)(1), if the flight-control system includes functions that act automatically to initiate recovery before the end of the 20 second period specified in § 25.335(b)(1), V ^D /M ^D must be determined from the greater of the speeds resulting from conditions (a) and (b) below. The speed increase occurring in these maneuvers may be calculated, if reliable or conservative aerodynamic data are used. (1) From an initial condition of stabilized flight at V ^C /M ^C , the airplane is upset so as to take up a new flight path 7.5 degrees below the initial path. The pilot implements a control application to try to maintain this new flight path up to full authority. Twenty seconds after initiating the upset, manual recovery is made at a load factor of 1.5 g (0.5 acceleration increment), or such greater load factor the system automatically applies with the pilot's pitch control neutral. Power, as specified in § 25.175(b)(1)(iv), is assumed until the pilot initiates a recovery, at which time power reduction and the use of pilot-controlled drag devices may be used. (2) From a speed below V ^C /M ^C , with power to maintain stabilized level flight at this speed, the airplane is upset so as to accelerate through V ^C /M ^C at a flight path 15 degrees below the initial path (or at the steepest nose-down attitude that the system will permit with full control authority if less than 15 degrees). The pilot's controls may be in the neutral position after reaching V ^C /M ^C and before recovery is initiated. Three seconds after a high-speed warning system annunciation, the pilot may initiate recovery by applying a load of 1.5g (0.5 acceleration increment), or such greater load factor that is automatically applied by the system with the pilot's pitch control neutral. Power may be reduced simultaneously. All other means of decelerating the airplane, the use of which is authorized up to the highest speed reached in the maneuver, may be used. The interval between successive pilot actions must not be less than one second. (b) The applicant must also demonstrate that the speed margin, established as above, will not be exceeded in inadvertent, or gust induced, upsets resulting in initiation of the dive from non-symmetric attitudes, unless the flight-control laws protect the airplane from getting into non-symmetric upset conditions. The upset maneuvers described in Advisory Circular 25-7D, “Flight Test Guide For Certification of Transport Category Airplanes,” paragraphs 10.2.3.3.1 and 10.2.3.3.3, paragraphs c.(3)(a) and (c) may be used to comply with this requirement. (c) Any failure of the high-speed protection system that would result in an airspeed exceeding those determined by conditions (a) and (b), above, must have a probability of occurrence of less than 1E-5 per flight hour. (d) Failures of the system must be annunciated to the pilots. Flight manual instructions must be provided that reduce the maximum operating speeds, V ^MO /M ^MO . The operating speed must be reduced to a value that maintains a speed margin between V ^MO /M ^MO and V ^D /M ^D that is consistent with showing compliance with § 25.335(b) without the benefit of the high-speed protection system. (e) Dispatch of the airplane with the high-speed protection system inoperative could be allowed under an approved minimum equipment listing that would require flight manual instructions to indicate reduced maximum operating speeds, as described in condition (d), above. In addition, the cockpit display of the reduced operating speeds, and the overspeed warning for exceeding those speeds, must be equivalent to that of the normal airplane with the high-speed protection system operative. It must also be shown that no additional hazards are introduced with the high-speed protection system inoperative. Issued in Kansas City, Missouri, on July 20, 2022. Patrick R. Mullen, Manager, Technical Innovation Policy Branch, Policy and Innovation Division, Aircraft Certification Service. [FR Doc. 2022-16558 Filed 8-2-22; 8:45 am]