1、The Engineering Society For Advancing Mobility Land Sea Air and Space I N T E R N A T I O N A L400 Commonwealth Drive, Warrendale, PA 15096-0001AEROSPACESTANDARDCopyright 1996 Society of Automotive Engineers, Inc.All rights reserved.Printed in U.S.ASAE Technical Standards Board Rules provide that: “
2、This report is published by SAE to advance the state of technical andengineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use,including any patent infringement arising therefrom, is the sole responsibility of the user.”SAE revie
3、ws each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invitesyour written comments and suggestions.Submitted for recognition as an American National StandardREV.AFOREWORDChanges in the revision are format/editorial only.1. SCOPE:This SAE Ae
4、rospace Standard (AS) covers automatic pilots intended for use on aircraft to automatically operate the primary and trim aerodynamic controls to maintain stable flight and/or to provide maneuvering about any of the three axes through servo control. Automatic control functions essential for primary o
5、r augmented flight control are excluded.1.1 Purpose:To establish essential minimum safe performance standards for automatic pilots primarily for use with turbine powered subsonic transport aircraft, the operation of which may subject the instrument to the environmental conditions specified in Sectio
6、n 3.3.2. APPLICABLE DOCUMENTS:The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict
7、between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1 NTIS Publications:Available from NTIS, Springfield, VA 22161.NACA
8、 Report 1235Issued 1963-02Revised 1996-09AUTOMATIC PILOTS(Turbine Powered Subsonic Aircraft)AS440SAE AS440 Revision A- 2 -3. GENERAL REQUIREMENTS:3.1 Material and Workmanship:3.1.1 Materials: Materials shall be of quality which experience and/or tests have demonstrated to be suitable and dependable
9、for use in aircraft instruments.3.1.2 Workmanship: Workmanship shall be consistent with high grade aircraft instrument manufacturing practice.3.2 Identification:The following information shall be legibly and permanently marked on each of the components or attached thereto:a. Name of unitb. SAE AS440
10、Ac. Manufacturers part numberd. Manufacturers serial number or date of manufacturee. Manufacturers name and/or trademarkf. Range (if applicable)g. Rating (if applicable)h. Explosion category (if applicable)3.3 Environmental Conditions:The following conditions have been established as minimum design
11、requirements. Tests shall be conducted as specified in Sections 5, 6, and 7.3.3.1 Temperature: When installed in accordance with the instrument manufacturers instructions, the instrument shall function over the range of ambient temperatures as listed in Column A below and shall not be adversely affe
12、cted by exposure to the temperature shown in Column B below.TABLE 1Instrument Location A BPower Plant Accessory CompartmentPressurized AreasNon-Pressurized or External Areas-30 to 150C-30 to 50 C-55 to 70 C-65 to 150 C-65 to 70 C-65 to 70 CSAE AS440 Revision A- 3 -3.3.2 Altitude: When installed in a
13、ccordance with the instrument manufacturers instructions, the instrument shall function from sea level up to the altitudes and temperatures listed below. Altitude pressure values are per NACA Report 1235. The instrument shall not be adversely affected following exposure to extremes in ambient pressu
14、re of 50 and 3 inches Hg absolute respectively.TABLE 23.3.3 Vibration: When installed in accordance with the instrument manufacturers instructions, the instrument shall function and shall not be adversely affected when subjected to vibrations of the following characteristics.TABLE 33.3.4 Humidity: T
15、he instrument shall function and shall not be adversely affected following exposure to any relative humidity in the range of 0 to 95% at a temperature of approximately 70 C.Instrument Location Altitude TemperaturePower Plant Accessory CompartmentPressurized AreasNon-Pressurized or External Areas50,0
16、00 feet15,000 feet50,000 feet80 C50 C20 CInstrument LocationFreq.CyclesPer SecondMax. DoubleAmplitudeInchesMax.Accel.Nacelle, Nacelle MountsWings, Empennage, and Wheel WellsFuselageForward of Spar AreaCenter of Spar AreaAft of Spar AreaVibration Isolated RackInstrument Panel5-10005-5005-10005-500500
17、-10005-10005-3030-10000.0360.0360.0360.036-0.0300.020-10 g2 g4 g7 g5 g1 g-0.25 gSAE AS440 Revision A- 4 -3.4 Explosion Category:The instrument component, when intended for installation either in uninhabited areas of non-pressurized aircraft or in non-pressurized areas of pressurized aircraft, shall
18、not cause an explosion when operated in an explosive atmosphere. The component shall meet the requirements applicable to the explosion category below. Specifically, any instrument component which can be an ignition source and is intended for installation in an area which combustible fluid or vapor m
19、ay result from abnormal conditions, e.g., fuel line leakage, shall meet the requirements of Category I. If the intended location is an area where combustible fluid or vapor can occur during normal operation, e.g., fuel tank, the instrument component shall meet the requirements of Category II, listed
20、 below:TABLE 43.5 Fire Hazard:The instrument shall be so designed to safeguard against hazards to the aircraft in the event of malfunction or failure, and the maximum operating temperature of surfaces of any instrument component contacted by combustible fuel or vapor shall not exceed 200 C due to se
21、lf-heating. Category Definition RequirementsIIIIIIIVExplosion Proofed: case not designedto preclude flame or explosion propagation.Explosion Proofed: case designed topreclude flame or explosion propagation.Hermetically SealedInstrument not capable of causing anexplosion.Paragraph 7.3.1Paragraph 7.3.
22、2Paragraphs 7.7 and6.1.2.1Shall not be capable of producing a capacitive or inductive spark of more than 0.2 millijoules of energy or a contact spark of more than 4.0 millijoules of energy.SAE AS440 Revision A- 5 -3.6 Radio Interference:The instrument shall not be the source of objectionable interfe
23、rence, under operating conditions at any frequencies used on the aircraft, either by radiation or feedback, in electronic equipment installed in the same aircraft as the instrument.3.7 Magnetic Effect:The magnetic effect of the instrument shall not adversely affect the performance of other instrumen
24、ts installed in the same aircraft.3.8 Icing:All components except those located in pressurized areas which are mechanically coupled to the primary or trim aerodynamic controls shall function when exposed to icing as would be encountered under conditions of rapid changes in temperature, pressure and
25、humidity. 4. DETAIL REQUIREMENTS:4.1 Controls:4.1.1 Disengagement: Positive means shall be provided to disengage the automatic pilot from the aircrafts aerodynamic and trim control system. This means shall not depend upon aircraft power (electric or pressure) for actuation nor its actuation preclude
26、d by electrical shorts.4.1.2 Quick Release: Means shall be provided for a quick release of the automatic pilot by utilization of a switch located on the control wheel.4.1.3 Controller: When a controller is provided, the design shall be such that, when installed in the aircraft, each manually operate
27、d control means which actuates the primary and/or trim aerodynamic controls shall operate in the plane with the sense of direction of motion of the aircraft. The control sensing shall be plainly identified on or adjacent to each control.4.2 Indications:4.2.1 Means of Indication: The means of indicat
28、ion required in the following paragraphs shall include any means by which the pilot is made cognizant of the condition, including control behavior and excluding control switch position.4.2.2 Servo Input Indication: Means shall be provided to indicate the direction and relative magnitude of the surfa
29、ce hinge moment for the autopilot engaged condition. This may be accomplished by displaying servo input for electric servos or differential ram pressure for hydraulic or pneumatic servos. With the autopilot not engaged, the servo signals present shall be indicated.SAE AS440 Revision A- 6 -4.2.3 Serv
30、o Power Indication: Means shall be provided to indicate when the servos are mechanically engaged but are not electrically energized, if such condition is possible.4.2.4 Power Malfunction Indication: Means shall be incorporated in the instrument to indicate when adequate power (pressure, voltage and/
31、or current) is not being made available to all phases required for the proper operation of the instrument. The indicating means shall indicate this malfunction in a positive manner.4.2.5 Airborne Navigation Reference Indication: A visual means shall be provided to show the pilot when the automatic p
32、ilot is not engaged to the airborne navigation reference.4.2.6 Automatic Pilot Disengage Indication: Means shall be provided to indicate when the autopilot has automatically disengaged due to the operation of an automatic interlock.4.2.7 Automatic Trim Disengage Indication: If there is an automatic
33、or manual disengage device associated with the trim system, means shall be provided for a trim disengage warning.4.3 Control Range:4.3.1 Corrective Control: The automatic pilot shall be capable of restoring the aircraft to the commanded attitude about the three axes throughout the following minimum
34、ranges:a. Pitch 50b. Roll 75c. Yaw 204.3.2 Commanded Control: Means shall be provided to limit maneuvering the aircraft through the automatic pilot controls, to the following maximum ranges:a. Pitch 30b. Bank 45c. Turn Unlimited Angle to Right or LeftEach control shall be so arranged that smooth and
35、 gradual inputs may be made therewith.4.4 Safety Provisions:4.4.1 System Interlock: Means shall be provided to prevent the automatic pilot engagement until it has reached a fully operable condition.4.4.2 Servo Force: means shall be provided to limit the maximum servo forces to a safe value as determ
36、ined in specific applications. The servos shall be designed to withstand a minimum load of 2.5 times the maximum output of the servo applied in a manner similar to that found in actual installations, or as required by the actual aircraft control loads, whichever is the higher, plus any approved load
37、 applied by rigging tension.SAE AS440 Revision A- 7 -4.4.3 Gyro Caging: If a gyro caging means is provided it shall not be capable of locking the gyro in a caged position. Any malfunction which causes the gyro to remain caged shall be indicated in a positive manner.4.4.4 Auxiliary Controls: There sh
38、all be no objectionable electrical interference between automatic pilot and the accessory equipment designed to be operated with it. The automatic pilot shall not be the source of objectionable interference caused by radiation or feedback.Special features incorporated as a part of the Automatic Pilo
39、t design, as integral or accessory components of the automatic pilot shall provide positive mechanical and/or electrical interlocks and sequencing in the order of engagement to preclude improper operation. For example:a. Altitude Control - Pitch attitude correction shall be limited.b. Flight Path Co
40、ntrol - Pitch and roll attitude correction shall be limited.c. Automatic Disengagement Control.d. Automatic Trim Control.e. Automatic Engine Power Control.f. Automatic Mach/Airspeed Control.g. Gyro Gaging.h. Yaw Damper.4.4.5 Automatic Trim: If an automatic trim system is provided, it shall disconnec
41、t for the case of a runaway malfunction if such is possible. If the malfunction is passive in that there is no automatic trim, disconnect shall occur and/or a means of indication of aircraft trim condition provided.4.5 Reliability:The automatic pilot system design shall be such that should a single
42、malfunction (except gyro mechanical failures) occur in the system, sustained maximum servo control forces, as determined in Paragraph 4.4.2, shall not be applied to the aircraft in more than one primary and trim aerodynamic axis.SAE AS440 Revision A- 8 -4.6 Power Variation:The instrument shall prope
43、rly function with plus or minus 15% variation in D.C. voltage and/or plus or minus 10% variation in A.C. voltage and plus or minus 5% variation in frequency or hydraulic pressure limits of plus or minus 30% of rated value. These values shall be steadystate conditions. Transient variations within the
44、se limits and variations beyond these limits shall not cause unsafe control. As the specific application requires, variations beyond these limits shall not cause damage to the automatic pilot producing unsafe conditions.5. TEST CONDITIONS:5.1 Atmospheric Conditions:Unless otherwise specified herein,
45、 all tests required by this Aerospace Standard shall be conducted at an atmospheric pressure of approximately 29.92 inches of mercury, an ambient temperature of approximately 25 C and a relative humidity not greater than 85%. When tests are conducted with atmospheric pressure or temperature substant
46、ially different from these values, allowance shall be made for the variations from the specified conditions.5.2 Vibration to Minimize Friction:Unless otherwise specified, all tests for performance may be conducted with the instrument subjected to a maximum vibration of 0.001 inch double amplitude at
47、 a frequency of 10 to 60 cycles per second. The term double amplitude, as used herein indicates the total displacement from positive maximum to negative maximum.5.3 Vibration Equipment:Vibration equipment shall be such as to allow vibration to be applied along each of three mutually perpendicular ax
48、es of the instrument at frequencies and amplitudes consistent with the requirements of Paragraph 3.3.3.5.4 Power Conditions:Unless otherwise specified, all tests shall be conducted at the power rating recommended by the manufacturer.5.5 Position:Unless otherwise specified, all tests shall be conduct
49、ed with the instrument in its normal operating position.SAE AS440 Revision A- 9 -6. INDIVIDUAL PERFORMANCE REQUIREMENTS:All of the components of the complete system shall be subjected to tests by the instrument manufacturer to demonstrate specific compliance with this Aerospace Standard, including the following requirements where applicable.6.1 Dielectric:Each instrument shall be tested by the method of inspection listed in Paragraphs 6.1.1 and 6.1.2.6.1.1 Insulation Resistance: The insulation resistance measured at 200 volts D.C. for 5 seconds between al
