1、AEROSPACE RECOMMENDED PRACTICEARP419REV.AIssued 1957-11Reaffirmed 2008-02Revised 2001-10Automatic Pilot InstallationsFOREWORDChanges in this Revision are format/editorial only.TABLE OF CONTENTS1. SCOPE .31.1 Purpose.32. REFERENCES .32.1 Glossary of Terms .33. GENERAL REQUIREMENTS.54. DETAIL REQUIREM
2、ENTS .64.1 Mechanical64.1.1 Control Surface Actuators (Servos) 64.1.2 Engaging Systems 74.1.3 Follow-up Controls 74.1.4 Control Valves and Piping.84.1.5 Reference Components and Amplifiers 84.1.6 Controller and Function Selector Panel 84.1.7 General .84.2 Electrical .94.2.1 Power Supplies .94.2.2 Wi
3、ring94.2.3 Shielding and Grounding 94.2.4 Switches, Signal Devices and Interlocks 94.2.5 Engaging System94.2.6 Cockpit Control .9SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is en
4、tirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE inv
5、ites your written comments and suggestions. Copyright 2008 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior
6、written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE ARP419 Revision A- 2 -TABLE OF CONTENTS (Continued)4.3 Maintenance .104.3.1 Accessibi
7、lity 104.3.2 Clearances104.3.3 Replaceability104.3.4 Interchangeability104.3.5 Field Tester Provisions115. TESTS.115.1 Ground Tests.115.1.1 Mechanical Installation115.1.2 Electrical Installation .125.1.3 System Adjustments .125.1.4 System Operation .135.2 Flight Test145.2.1 Interlocks.145.2.2 Servo
8、Engage and Disengage 155.2.3 Servo Overpowering and Recovery 155.2.4 Stability - Normal Flight .155.2.5 Command Control.155.2.6 Altitude Control .165.2.7 Magnetic Heading Control 165.2.8 Throttle Control .165.2.9 Airspeed Control .165.2.10 Electrical Power Variation .165.2.11 Servo Force Limits 165.
9、2.12 Automatic Trim165.2.13 Radio - Automatic Pilot Coupler175.3 Post Flight .185.3.1 Mechanical185.3.2 Electrical .18APPENDIX A INSTALLATION SURVEY FORM19SAE ARP419 Revision A- 3 -1. SCOPE:These recommendations cover the mechanical and electrical installation and installation test procedures for au
10、tomatic pilots of the type normally used in transport type aircraft. The material in this ARP does not supercede any airworthiness requirement in the Civil Air Regulations.1.1 Purpose:This Aeronautical Recommended Practice is intended to outline Automatic Pilot installation design, performance, and
11、test recommendations for use as a guide by the aircraft industry.2. REFERENCES:“Design Manual on Aircraft Electrical Installations - Available from: Aircraft Industries Assn., 610 Shoreham Building, Washington 5, D.C.Specification MIL-W-5088B (ASG) “Installation of Aircraft Wiring“ - Available from:
12、 Commanding Officer, U.S. Naval Air Station, Johnsville, PennsylvaniaSpecification MIL-E-7894A (ASG) “Characteristics of Aircraft Electric Power“ - Available from: Commanding Officer, U.S. Naval Air Station, Johnsville, Pennsylvania, Attention: Technical Records DivisionCivil Aeronautics Manual 4 “A
13、ircraft Airworthiness“ - Available from: The Superintendent of Documents, U.S. Government Printing Office, Washington 25, D.C.Specification ANC-5 “Strength of Metal Aircraft Elements“ - Available from: The Superintendent of Documents, U.S. Government Printing Office, Washington 25, D.C.SAE Aeronauti
14、cal Standard AS402A “Automatic Pilots“ - Available from: Society of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE Aeronautical Recommended Practice ARP268A “Location and Actuation of Cockpit Controls for Commercial Transport type Aircraft“ - Available from: Societ
15、y of Automotive Engineers, Inc., 400 Commonwealth Drive, Warrendale, PA 15096-0001.RTCA Paper 151-56/DO-74 “Automatic Flight“ - Available from: Radio Technical Commission for Aeronautics., Room 2036, Building T-5, 16th in a hydraulic system, a pressure. A signal may be generated by a sensor, control
16、ler or selector or other such reference device.THROTTLE CONTROL: A function or mode of operation which provides power or throttle control in response to pitch attitude, glide slope, or airspeed signals.TRANSIENT: A temporary deviation of the aircraft from its normal attitude produced by momentarily
17、overpowering the automatic controls or by momentarily injecting a signal to cause a deviation.TRIM INDICATOR: An instrument used to indicate the relative amount of servo effort being used to maintain the aircraft trim.UNDERSHOOT: Movement of the aircraft whereby it stops short of the commanded refer
18、ence altitude, attitude or flight path, before settling out.3. GENERAL REQUIREMENTS:3.1 Equipment:The automatic pilots referred to herein should conform to Aeronautical Standard AS402A.3.2 Materials:Materials should be of a quality which experience and/or tests have demonstrated to be suitable and d
19、ependable for aircraft use.3.3 Workmanship:Workmanship should be consistent with high grade aircraft manufacturing practice.3.4 Environmental Conditions:The design of the installation should be such that satisfactory performance may be obtained under the environmental conditions to which the aircraf
20、t may be subjected.SAE ARP419 Revision A- 6 -3.5 Installation Survey and Component Selection:In order to provide information relative to the aircraft aerodynamic and structural characteristics, an “Installation Survey“ form is included as Appendix “A“ of this ARP. The aircraft manufacturer should, t
21、o the best of his ability with respect to the aircraft design status, supply the automatic pilot manufacturer with the information called for on this form. Along with this survey the aircraft manufacturer should also specify any automatic pilot component characteristics which may be deemed necessary
22、 to provide a closer integration of the automatic pilot with the basic aircraft control system.On the basis of this information, the automatic pilot manufacturer should then design, select, and combine the necessary components into a comprehensive system which can be expected to perform the desired
23、and necessary functions in accordance with AS402A, and not induce aerodynamic or structural loads in excess of the design limits specified by the aircraft manufacturer. Final values of maximum servo forces and signal calibration should be checked and determined on the basis of flight tests of the in
24、itial installation.4. DETAIL REQUIREMENTS:4.1 Mechanical:4.1.1 Control Surface Actuators (Servos):4.1.1.1 Location and Mounting: The location and mounting of the servo should be carefully considered from the standpoint of control system friction, preloads, lost motion, and other such characteristics
25、 which would tend to cause automatic control difficulties.Locations should also be chosen to permit the shortest practicable connecting cables or links. Adequate clearance should be provided between the moving parts of the servo and adjacent structure to prevent possible jamming by foreign objects.T
26、he servo mounting bracket should be designed with sufficient rigidity to prevent any detrimental deflection under conditions of maximum servo force. The use of vibration isolators should not be considered.4.1.1.2 Connections and Rigging: The servo should be connected to the main control system so th
27、at it will produce uniform force and displacement in both directions of operation. In servo installations utilizing cable control, a parallel cable installation is preferred over the series installation. Cable installations designed for direct attachment to a bell crank or surface horn should be mad
28、e through a suitable sector designed as an integral part of the horn or bell crank. The design of the sector should be such that full travel of the control system will provide a negligible change in servo cable tension. Where the cable runs over the servo drum, and has an angular motion with respect
29、 to the plane of the drum, the maximum misalignment resulting from this motion should not exceed 1 degree for the neutral position of the controls nor 3 degrees for any position between half and full movement of the controls. Each servo cable keeper should be positioned as close as possible to the p
30、oint of tangency between the servo drum and cable.SAE ARP419 Revision A- 7 -4.1.1.2 (Continued):Care should be taken in the design of the cable routing to prevent the possibility of foreign objects from lodging between the cable and the drum. If necessary, a suitable guard should be installed.All co
31、ntrol routing to the servos should be designed such that the minimum amount of friction will be added to the aircraft control system. Cabling details should be consistent with the general design practices which have been carried out in the manual control system. (See references 4 and 5).4.1.2 Engagi
32、ng Systems:4.1.2.1 Cockpit Controls: If mechanical engaging and/or disengaging is utilized, the cockpit control handle should be so located that it is readily accessible to both pilot and copilot and as close to the flight controller and as distinctive in method and direction of operation as practic
33、able. Forward or upward motion of the cockpit control should engage the automatic pilot system while motion in the opposite directions should disengage. (If engaging and disengaging is accomplished electrically the motion of the control switch handle shall be similar.) If necessary, the control hand
34、le should be provided with suitable guard to prevent inadvertent operation of the automatic pilot. The handle should be so located to enable a force not to exceed 35 pounds to be readily applied.4.1.2.2 Cables or Rod Controls: All Control Cables and/or Control Rods used in a mechanical engaging syst
35、em should be routed that they provide the minimum of friction. A maximum load of 35 pounds should be presented to the pilot at the cockpit control. This load should be the total of the friction plus disconnect load.4.1.3 Follow-up Controls:4.1.3.1 Location: To permit the minimum of lost motion or de
36、adspot to be maintained in the connecting linkage the follow-up control unit, if not a part of the servo, should be located in the control cable system as near as possible to the servo drum or other portion of the control system, the movement of which is being measured.4.1.3.2 Connection and Mountin
37、g: Follow-up control units may be mounted in any position, but provisions should be made to enable either the shaft or the housing of the unit to be rotated for orientations of the electrical signal element. Connections should be made to the control system by means of push-pull rods and ball joints,
38、 control cables, or other suitable means which will transmit motion of the control system to the follow-up control unit shaft without lost motion. The connecting linkage should be such that the movement of the control system through its full travel will rotate the follow-up control shaft safely with
39、in the limits of its mechanical range, and in a manner compatible with system requirements (e.g., a linear or non-linear function).SAE ARP419 Revision A- 8 -4.1.4 Control Valves and Piping: Electro-hydraulic control valves should be located immediately adjacent to their respective hydraulic boost or
40、 power control valves on the pilots side of the boost, where applicable. They should be mounted securely in such a manner so as to prevent misalignment and/or twisting of any actuated parts.All hydraulic piping and valves should be kept out of the cockpit area and away from oxygen lines or equipment
41、, wherever possible.4.1.5 Reference Components and Amplifiers: Accelerometers, pendulums, rate and displacement gyros, or other such reference devices should be installed such that their orientation, and location with respect to the aircrafts axes and center of gravity, will be in accordance with th
42、e manufacturers recommendations.The altitude sensor should be located as near as practicable to the source of static pressure, and suitably shock-mounted and oriented in a manner to preclude any undesirable effects of vibration and acceleration.Amplifiers and coupling units should be mounted so as t
43、o allow accessibility to all tap switch or potentiometer adjustments.4.1.6 Controller and Function Selector Panel: These units should be situated side by side and located in a position that is visible and readily accessible for operation by both pilot and copilot in their normal positions. The axes
44、of the controller knobs or wheels should be oriented with those of the aircraft.The function selector panel should be adequately lighted for night use. Where toggle switches are used, the function should be switched “ON“ by a forward, or upward motion of the switch handle.4.1.7 General:4.1.7.1 Mount
45、ing Brackets: All mounting brackets should be designed to provide adequate strength, freedom from vibration and flexing that would interfere with the satisfactory operation of the automatic pilot under any flight conditions encountered in service.4.1.7.2 Ventilation: All components should be install
46、ed in accordance with the temperature requirements of the equipment. If it is impossible to so locate the equipment in the aircraft which has temperature similar to that required, then provisions to direct cooling air to this equipment must be made.4.1.7.3 Safety: All attaching fittings and fastener
47、s such as bolts, nuts, clevis pins, etc., if not of the self locking type should be locked with safety wire or cotter pins.4.1.7.4 Bonding: The chassis or mounting frames of all components should be electrically bonded to the aircraft structure. All mating surfaces which conduct a ground return shou
48、ld be clear of paint, anodized coating or other non-conducting materials.SAE ARP419 Revision A- 9 -4.1.7.5 Shock Mounts: The installation of connectors and connecting cables should be designed to minimize the effect of their added weight on vibration-isolated equipment. This item assumes greater imp
49、ortance where light-weight components are shock-mounted and the added weight of the attached cable and connector constitutes a significant part of the shock-mount load.4.2 Electrical:4.2.1 Power Supplies: The design of the electrical installation and the selection of the power supply components should conform to the best aeronautical practice and shall have ample capacity for cold starts to be encountered in service. Intermittent loads, other than the automatic pilot should be carefully considered with regard to automatic pilot performance. Where variatio
