FLYING QUALITIES OF PILOTED AIRCRAFT - CAFE Foundation

MIL–STD–1797A4.1.8.2 Devices for indication, warning, prevention, and recovery. It is intended that dangerous flightconditions be eliminated and the requirements of this standard met by appropriate aerodynamic design andmass distribution, rather than through incorporation of a special device or devices. As a minimum, thesedevices shall perform their function whenever needed but shall not limit flight within the Operational FlightEnvelope. Neither normal nor inadvertent operation of such devices shall create a hazard to the aircraft. ForLevels 1 and 2, nuisance operation shall not be possible. Functional failure of the devices shall be indicated tothe pilot.4.1.9 Interpretation of subjective requirements. In several instances throughout the standard, subjectiveterms such as objectionable flight characteristics, realistic time delay, normal pilot technique and excessiveloss of altitude or buildup of speed, have been employed where insufficient information exists to establishabsolute quantitative criteria. Final determination of compliance with requirements so worded will be made bythe procuring activity.4.1.10 Interpretation of quantitative requirements. Many of the numerical requirements of this standardare stated in terms of a linear mathematical description of classical aircraft. Certain factors, for example flightcontrol system nonlinearities and higher–order dynamics or aerodynamic nonlinearities, can cause anappreciable difference in the aircraft response apparent to the pilot from that of the linear model of the basicairframe. The contractor shall determine equivalent classical systems which have responses most closelymatching those of the actual aircraft. Then those numerical requirements of section 4 which are stated interms of linear system parameters (such as frequency, damping ratio and modal phase angles) apply to theparameters of that equivalent system rather than to any particular modes of the higher–order systemrepresentation. The adequacy of the response match between equivalent and actual aircraft, or alternativecriteria, shall be agreed upon by the contractor and the procuring activity. Nonlinearities or higher–orderdynamics that may exist shall not result in any objectionable (for Levels 1 and 2) or dangerous characteristics.4.1.11 General flying qualities requirements4.1.11.1 Buffet. Within the boundaries of the Operational Flight Envelope, there shall be no objectionablebuffet which might detract from the effectiveness of the aircraft in executing its intended missions. In thePermissible Flight Envelope _________.4.1.11.2 Release of stores. The intentional release or ejection of any stores shall not result in objectionableflight characteristics or impair tactical effectiveness for Levels 1 and 2. However, the intentional release orejection of stores shall never result in dangerous or intolerable flight characteristics. This requirement appliesfor all flight conditions and store loadings at which normal or emergency release or ejection of the store ispermissible.4.1.11.3 Effects of armament delivery and special equipment. Operation of movable parts such asbomb bay doors, cargo doors, armament pods, refueling devices and rescue equipment, or firing of weapons,release of bombs, or delivery or pickup of cargo shall not cause buffet, trim changes, or other characteristicswhich impair the tactical effectiveness of the aircraft under any pertinent flight condition. These requirementsshall be met for Levels 1 and 2.4.1.11.4 Failures. No single failure of any component or system shall result in dangerous or intolerableflying qualities; Special Failure States (4.1.7.2) are excepted. The crew member concerned shall be givenimmediate and easily interpreted indications whenever failures occur that require or limit any flight crew actionor decision. The aircraft motions following sudden aircraft system or component failures shall be such thatdangerous conditions can be avoided by the pilot, without requiring unusual or abnormal corrective action. Arealistic time delay of at least _________ between the failure and initiation of pilot corrective action shall beincorporated when determining compliance. This time delay shall include an interval between the occurrenceof the failure and the occurrence of a cue such as acceleration, rate, displacement, or sound that will definitely24