Source: https://www.federalregister.gov/documents/2007/02/26/E7-3213/special-conditions-dassault-aviation-model-falcon-7x-airplane-side-stick-controllers-electronic
Timestamp: 2017-08-22 06:10:33
Document Index: 389464

Matched Legal Cases: ['art 34', 'art 36', '§\u2009611', 'art 25', 'art 25', 'art 25', '§\u200925', 'art 25', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925', '§\u200925']

A Proposed Rule by the Federal Aviation Administration on 02/26/2007
We must receive your comments by March 28, 2007.
72 FR 8296
8296-8303 (8 pages)
Notice No. 25-07-06-SC
E7-3213
Proposed Special Condition No. 1. Side Stick Controllers
Proposed Special Condition No. 2. Electronic Flight Control System: Lateral-Directional Stability, Longitudinal Stability, and Low Energy Awareness
Proposed Special Condition No. 3. Electronic Flight Control System: Flight Control Surface Position Awareness
Proposed Special Condition No. 4. Electronic Flight Control System: Flight Characteristics Compliance Via the Handling Qualities Rating Method (HQRM)
Proposed Special Condition No. 5. Flight Envelope Protection: General Limiting Requirements
Proposed Special Condition No. 6. Flight Envelope Protection—High Incidence Protection Function
Proposed Special Condition No. 7. Flight Envelope Protection: Normal Load Factor (G) Limiting
Proposed Special Condition No. 8. Flight Envelope Protection: Pitch, Roll, and High Speed Limiting Functions
https://www.federalregister.gov/d/E7-3213 https://www.federalregister.gov/d/E7-3213
This action proposes special conditions for the Dassault Aviation Model Falcon 7X airplane. This airplane will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. These design features include side stick controllers, electronic flight control systems, and flight envelope protections. These special conditions pertain to control and handling qualities of the airplane and protection limits within the normal flight envelope. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. These proposed 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. Additional special conditions will be issued for other novel or unusual design features of the Dassault Model Falcon 7X airplanes.
You must mail two copies of your comments to: Federal Aviation Administration, Transport Airplane Directorate, Attn: Rules Docket (ANM-113), Docket No. NM370, 1601 Lind Avenue, SW., Renton, Washington, 98057-3356. You may deliver two copies to the Transport Airplane Directorate at the above address. You must mark your comments: Docket No. NM370. You can inspect comments in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
Joe Jacobsen, FAA, Airplane and Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-2011; facsimile (425) 227-1149.
On June 4, 2002, Dassault Aviation, 9 rond Point des Champs Elysees, 75008, Paris, France, applied for FAA type certificate for its new Model Falcon 7X airplane. The Dassault Model Falcon 7X airplane is a 19 passenger transport category airplane powered by three aft mounted Pratt & Whitney PW307A high bypass ratio turbofan engines. Maximum takeoff weight will be 63,700 pounds, and maximum certified altitude will be 51,000 feet with a range of 5,700 nautical miles. The airplane is operated using a fly-by-wire (FBW) primary flight control system. This will be the first application of a FBW primary flight control system in an airplane primarily intended for private/corporate use.
In addition to the applicable airworthiness regulations and special conditions, the Dassault Model Falcon 7X 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. In addition, the FAA must issue a finding of regulatory adequacy under § 611 of Public Law 93-574, the “Noise Control Act of 1972.”
Electronic flight control system: lateral-directional and longitudinal stability, low energy awareness, Start Printed Page 8297
Because of these rapid improvements in airplane technology, the applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. These proposed special conditions address equipment which may affect the airplane's structural performance, either directly or as a result of failure or malfunction. These proposed special conditions are identical or nearly identical to those previously required for type certification of other airplane models. Additional special conditions will be issued for other novel or unusual design features of the Dassault Model Falcon 7X airplane. Those additional special conditions will pertain to the following topics:
Dive speed definition with speed protection system,
Sudden engine stoppage, and
Operation without normal electrical power.
Final special conditions have been issued for the Model Falcon 7X with the novel or unusual design feature pertaining to Pilot Compartment View-Hydrophobic Coatings in Lieu of Windshield Wipers (January 10, 2007; 72 FR 1135). Special conditions have been proposed for the Model Falcon 7X with the novel or unusual design features pertaining to Interaction of Systems and Structures, Limit Pilot Forces, and High Intensity Radiated Fields (HIRF) (October 18, 2006; 71 FR 61427).
Because of these rapid improvements in airplane technology, the applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. Therefore, in addition to the requirement of part 25, subparts C and D, the following special conditions are proposed.
These proposed special conditions require that the unique features of the side stick must be demonstrated through flight and simulator tests to have suitable handling and control characteristics.
The unique features of the Model Falcon 7X flight control system and side-stick controllers, when compared with conventional airplanes with wheel and column controllers, do not provide conventional awareness to the flightcrew of a change in speed or a change in the direction of flight. These special conditions require that adequate awareness be provided to the pilot of a low energy state (low speed, low thrust, and low altitude) below normal operating speeds.
With conventional control system requirements, positive static directional stability is defined as the tendency to recover from a skid with the rudder free. Positive static lateral stability is defined as the tendency to raise the low wing in a sideslip with the aileron controls free. These proposed special conditions are intended to accomplish the following:
The pitch control movement of the side stick is a normal load factor or “g” command which results in an initial movement of the elevator surface to attain the commanded load factor. That movement is followed by integrated movement of the stabilizer and elevator to automatically trim the airplane to a neutral (1g) stick-free stability. The flight path commanded by the initial side stick input will remain stick-free Start Printed Page 8298until the pilot gives another command. This control function is applied during “normal” control law within the speed range from the speed at the angle of attack protection limit to initiation of the angle of attack protection limit. Once outside this speed range, the control laws introduce the conventional longitudinal static stability as described above.
As a result of neutral static stability, the Falcon 7X does not meet the part 25 requirements for static longitudinal stability. It would not be appropriate to apply the conventional part 25 requirements for static longitudinal stability to the unconventional control systems of the Falcon 7X. These proposed special conditions would require that the airplane be shown to have suitable static longitudinal stability in any condition normally encountered in service.
Because § 25.173 requires that the pilot receive speed change cues through increased or decreased forces on the controller, it would be inappropriate to apply those requirements for feedback cues to the Falcon Model 7X systems. These proposed special conditions would require that the airplane provide adequate awareness of a low energy state to the pilot.
These special conditions would require that suitable annunciation be provided to the flightcrew when a flight condition exists in which nearly full control surface deflection occurs. Suitability of such a display must take into account that some pilot-demanded maneuvers (e.g., rapid roll) are necessarily associated with intended full or nearly full control surface deflection. Therefore, simple alerting systems which would function in both intended or unexpected control-limiting situations must be properly balanced between needed crew awareness and nuisance warnings.
The Model Falcon 7X airplane will have an electronic flight control system (EFCS). This system provides an electronic interface between the pilot's flight controls and the flight control surfaces (for both normal and failure states). The system also generates the actual surface commands that provide for stability augmentation and control about all three airplane axes. Because EFCS technology has outpaced existing regulations—written essentially for unaugmented airplanes with provision for limited ON/OFF augmentation—suitable special conditions and a method of compliance are required to aid in the certification of flight characteristics.
These special conditions and the method of compliance presented in Appendix 7, FAA Handling Qualities Rating Method, of AC 25-7A, Flight Test Guide Certification of Transport Category Airplanes, would provide a means to evaluate flight characteristics—for example, “satisfactory,” “adequate,” or “controllable”—to determine compliance with the regulations. The HQRM in Appendix 7 was developed for airplanes with control systems having similar functions and is employed to aid in the evaluation of the following:
The Handling Qualities Rating Method provides a systematic approach to the assessment of handling qualities. It is not intended to dictate program size or need for a fixed number of pilots to achieve multiple opinions. The airplane design itself and success in defining critical failure combinations from the many reviewed in Systems Safety Assessments would dictate the scope of any HQRM application.
Handling qualities terms, principles, and relationships familiar to the aviation community have been used to formulate the HQRM. For example, we have established that the well-known COOPER-HARPER rating scale and the proposed FAA three-part rating system are similar. This approach on the flying qualities of highly augmented/relaxed static stability airplanes in relation to regulatory and flight test guide requirements is reported in DOT/FAA/CT-82/130, Flying Qualities of Relaxed Static Stability Aircraft, Volumes I and II.
These special conditions and the following ones—pertaining to flight envelope protection—would present general limiting requirements for all the unique flight envelope protection features of the basic Model Falcon 7X Electronic Flight Control System (EFCS) design. Current regulations do not address these types of protection features. The general limiting requirements are necessary to ensure a smooth transition from normal flight to the protection mode and adequate maneuver capability. The general limiting requirements also ensure that the structural limits of the airplane are not exceeded. Furthermore, failure of the protection feature must not create hazardous flight conditions. Envelope protection parameters include angle of attack, normal load factor, pitch angle, and speed. To accomplish these envelope protections, one or more significant changes occur in the EFCS control laws as the normal flight Start Printed Page 8299envelope limit is approached or exceeded.
The Falcon 7X is equipped with a high incidence protection function that limits the angle of attack at which the airplane can be flown during normal low speed operation and that cannot be overridden by the flightcrew. This function prevents the airplane from stalling and therefore, the stall warning system is not needed during normal flight conditions. If there is a failure of the high incidence protection function that is not shown to be extremely improbable, the flight characteristics at the angle of attack for CLMAX must be suitable in the traditional sense, and stall warning must be provided in a conventional manner. This special condition would address these and other unique features of this function on the Model Falcon 7X.
The special conditions define aMIN imum steady flight speed, VMIN, to be demonstrated during flight test, at which the airplane can develop lift normal to the flight path and equal to its weight at the angle of attack limit of the protection function. It further defines procedures for establishing the reference stall speed, VSR, to be used for defining reference speeds during takeoff and landing.
Because Dassault has chosen to include this optional design feature on the Falcon 7X, for which part 25 does not contain adequate or appropriate safety standards, special conditions pertaining to this feature are included. These special conditions would establishMIN imum load factor requirements to ensure adequate maneuver capability during normal flight. Other limiting features of the normal load factor limiting function, as discussed above, that would affect the upper load limits are not addressed in these special conditions. The phrase “in the absence of other limiting factors” has been added relative to past similar special conditions to clarify that while the main focus is on the lower load factor limits, there are other limiting factors that must be considered in the load limiting function.
In addition to the requirements of § 25.143, this special condition would establish requirements to ensure that pitch and high speed limiting functions do not impede normal maneuvering and that pitch and roll limiting functions do not restrict or prevent attaining bank angles necessary for emergency maneuvering.
As discussed above, these special conditions are applicable to the Dassault Model Falcon 7X. Should Dassault Aviation apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design features, these special conditions would apply to that model as well.
This action affects only certain novel or unusual design features of the Dassault Model Falcon 7X airplane. It is not a rule of general applicability, and it affects only the applicant which applied to the FAA for approval of these features on the airplane.
Accordingly, pursuant to the authority delegated to me by the AdMIN istrator, the following special conditions are issued as part of the type certification basis for the Dassault Aviation Model Falcon 7X airplane.
a. Pilot strength: In lieu of the “strength of pilots” limits shown in Start Printed Page 8300§ 25.143(c) for pitch and roll, and in lieu of the specific pitch force requirements of §§ 25.145(b) and 25.175(d), it must be shown that the temporary and maximum prolonged force levels for the side stick controllers are suitable for all expected operating conditions and configurations, whether normal or non-normal.
In lieu of compliance with § 25.672(c), the HQRM contained in Appendix 7, FAA Handling Qualities Rating Method, of the Flight Test Guide for Certification of Transport Category Airplanes, AC 25-7A, (or an equivalent method of compliance found acceptable to the FAA), must be used for evaluation of EFCS configurations resulting from single and multiple failures not shown to be extremely improbable.
(b) Required safe and controllable maneuvering of the airplane, andStart Printed Page 8301
(c) Margins to critical conditions. Dynamic maneuvering, airframe and system tolerances (both manufacturing and in-service), and non-steady atmospheric conditions—in any appropriate combination and phase of flight-must not result in a limited flight—parameter beyond the nominal design limit value that would cause unsafe flight characteristics.
Electronic Flight Control System (EFCS) The electronic and software command and control elements of the flight control system.
High Incidence Protection Function An airplane level function that automatically limits the maximum angle of attack that can be attained to a value below that at which an aerodynamic stall would occur.
Alpha Limit The maximum angle of attack at which the airplane stabilizes with the high incidence protection function operating and the longitudinal control held on its aft stop.
VMIN The minimum steady flight speed is the stabilized, calibrated airspeed obtained when the airplane is decelerated at an entry rate not exceeding 1 knot per second, until the longitudinal pilot control is on its stop with the high incidence protection function operating.
V MIN1g VMIN corrected to 1g conditions. It is the minimum calibrated airspeed at which the airplane can develop a lift force normal to the flight path and equal to its weight when at an angle of attack not greater than that determined for VMIN.
b. Capability and Reliability of the High Incidence Protection Function.
c. Minimum Steady Flight Speed and Reference Stall Speed.
In lieu of the requirements of § 25.103, the following special conditions apply:
(1) VMIN The minimum steady flight speed, for the airplane configuration under consideration and with the high incidence protection function operating, is the final stabilized calibrated airspeed obtained when the airplane is decelerated at an entry rate not exceeding 1 knot per second until the longitudinal pilot control is on its stop.
n z w = load factor normal to the flight path at VMIN
(a) Engines idling or—if that resultant thrust causes an appreciable decrease in stall speed-not more than zero thrust at the stall speed
(6) The flight characteristics at the angle of attack for CLMAX must be suitable in the traditional sense at FWD and AFT center of gravity in straight Start Printed Page 8302and turning flight at IDLE power. Although for a normal production EFCS and steady full aft stick this angle of attack for CLMAX cannot be achieved, the angle of attack can be obtained momentarily under dynamic circumstances and deliberately in a steady state sense with some EFCS failure conditions.
(1) Normal Operation If the conditions of paragraph b, Capability and Reliability of the High Incidence Protection Function, of this special conditions are satisfied, a level of safety equivalent to that intended by § 25.207, Stall Warning, must be considered to have been met without provision of an additional, unique warning device.
(2) Failure Cases Following failures of the high incidence protection function not shown to be extremely improbable, if the function no longer satisfies paragraph b, Capability and Reliability of the High Incidence Protection Function, paragraphs b(1), (2), and (3) of this special condition, stall warning must be provided in accordance with § 25.207. The stall warning should prevent inadvertent stall under the following conditions:
e. High Incidence Handling Demonstrations.
In lieu of the requirements of § 25.201, the following special conditions apply:
f. High Incidence Handling Characteristics.
In lieu of the requirements of § 25.203, the following special conditions apply:
g. Atmospheric Disturbances.
Operation of the high incidence protection function must not adversely affect aircraft control during expected levels of atmospheric disturbances or impede the application of recovery procedures in case of windshear. Simulator tests and analysis may be used to evaluate such conditions but must be validated by limited flight testing to confirm handling qualities at critical loading conditions.
h. [Reserved].
i. Proof of Compliance.
In addition to the requirements of § 25.21, the following special conditions apply:
k. Airspeed Indicating System. Start Printed Page 8303
(1) In lieu of the requirements of § 25.1323(c)(1), the following special conditions apply:
(2) In lieu of the requirements of § 25.1323(c)(2), the following special conditions apply:
Issued in Renton, Washington, on February 15, 2007.
[FR Doc. E7-3213 Filed 2-23-07; 8:45 am]