means are provided to detect and correct the overheat condition during flight. (g) Electric shock exposure. No probable malfunction in the system should expose crew or passengers to harmful electric shock, during any normal activity on the aircraft. [Supp. 29, 21 F. R. 2747, Apr. 28, 1956] § 4b.606-2 Installation of flight recorders (FAA policies which apply to § 4b.606). Flight recorders required under Parts 40, 41, and 42 of this subchapter as amended should be installed in the airplane in conformance with the following: (a) Location of flight recorder. The recorder should be located in accordance with the applicable type in the following: Type I-Unrestricted location, Type II-Restricted to any location more than one-half of the wing root chord from the main wing structure through the fuselage and from any fuel tanks, sensing. Type III-Unrestricted location. (b) Vertical acceleration (1) The vertical acceleration forces should be sensed at a location within or adjacent to the fuselage, and within or as close to the center of gravity range of the airplane as practicable. (2) The vertical acceleration sensor, or the unit in which it is contained, should be attached to a rigid structural member of the airplane so that vertical acceleration forces present in that area can be sensed with a minimum of error. (3) Sensing of only the in-flight vertical acceleration forces is necessary; impact forces need not be sensed. (c) Connection to sources of data. The air speed, altitude, and heading data should be obtained from either 2 a required duplicate instrument, or from a source independent of required flight and navigation instrument systems, or a combination thereof. No connection should be made within the case itself of If the required altimeter indicators. data are obtained from an independent source, such source should provide data which has an accuracy equivalent to corresponding data furnished by required flight and navigation instrument sys * See § 4b.612 (f) for requirements concerning the connection of additional instruments to required duplicate and duplicated instrument systems. tems. Provisions need not be made to disconnect or isolate the recorder in flight from sources of data which are independent of required flight and navigation instruments. (d) Connection to electrical power. The flight recorder should be connected to a bus of maximum reliability when such connection does not jeopardize service to essential or emergency loads. If service to such loads is affected, the recorder should be connected to a bus of the next lower reliability. [Supp. 39, 23 F. R. 7482, Sept. 26, 1958] INSTRUMENTS; INSTALLATION The provisions of §§ 4b.611 through 4b.613 shall apply to the installation of instruments. NOTE: It may be necessary to duplicate certain instruments at two or more crew stations to meet the instrument visibility requirements prescribed in § 4b.611, or when required by the operating rules of the Civil Air Regulations for reliability or cross-check purposes in particular types of operations. In the latter case, independent operating systems would be required in accordance with the provisions of § 4b.612 (f). [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-2, 20 F. R. 5308, July 26, 1955] § 4b.611 Arrangement and visibility of instrument installations. (a) Flight, navigation, and powerplant instruments for use by each pilot shall be plainly visible to him from his station with the minimum practicable deviation from his normal position and line of vision when he is looking out and forward along the flight path. (b) Flight instruments required by § 4b.603 shall be grouped on the instrument panel and centered as nearly as practicable about the vertical plane of the pilot's forward vision. The four basic instruments specified in subparagraphs (1) through (4) of this paragraph shall be located on the flight instrument panel as follows: (1) The top center position on the panel shall contain that instrument which, of all instruments on the panel, most effectively indicates attitude. (2) The position adjacent to and directly to the left of the top center position shall contain that instrument which, of all instruments on the panel, most effectively indicates air speed. (3) The position adjacent to and directly to the right of the top center position shall contain that instrument which, of all instruments on the panel, most effectively indicates altitude. (4) The position adjacent to and directly below the top center position shall contain that instrument which, of all instruments on the panel, most effectively indicates direction of flight. (c) All the required powerplant instruments shall be closely grouped on the instrument panel. (d) Identical powerplant instruments for the several engines shall be located to prevent any misleading impression as to the engines to which they relate. (e) Powerplant instruments vital to the safe operation of the airplane shall be plainly visible to the appropriate crew members. (f) The vibration characteristics of the instrument panel shall be such as not to impair seriously the accuracy of the instruments or to damage them. [15 F.R. 3543, June 8, 1950, as amended by Amdt. 4b-8, 18 F.R. 2216, Apr. 18, 1953; Amdt. 4b-7, 22 F.R. 7462, Sept. 19, 1957] § 4b.611-1 Procedure for checking arrangement and visibility of instrument installations (FAA policies which apply to § 4b.611). The arrangement and visibility of the instruments should be checked throughout the type tests in order to supply the information which is necessary to complete the pertinent portions of Form ACA 283-4b, Type Inspection Report. [Supp. 24, 19 F.R. 4466, July 20, 1954] § 4b.612 Flight and navigational instru ments. (a) Air-speed indicating systems. (1) Air-speed indicating instruments shall be of an approved type and shall be calibrated to indicate true air speed at sea level in the standard atmosphere with a minimum practicable instrument calibration error when the corresponding pilot and static pressures are applied to the instrument. (2) The air-speed indicating system shall be calibrated to determine the system error, i. e., the relation between IAS and CAS, in flight and during the accelerated take-off ground run. The ground run calibration shall be obtained from 0.8 of the minimum value of V1 to the maximum value of V2, taking into account the approved altitude and weight range for the airplane. In the ground run calibration, the flap and power settings shall correspond with the values determined in the establishment of the take-off path under the provisions of § 4b.116, assuming the critical engine to fail at the minimum approved value of V1. (3) The air-speed error of the installation, excluding the air-speed indicator instrument calibration error, shall not exceed 3 percent or 5 mph, whichever is the greater, throughout the speed range from VNo to 1.3 Vs, with flaps retracted, and from 1.3 Vs, to VEE with flaps in the landing position. FB (4) The air-speed indicating system shall be arranged in so far as practicable to preclude malfunctioning or serious error due to the entry of moisture, dirt, or other substances. (5) The air-speed indicating system shall be provided with a heated pitot tube or equivalent means of preventing malfunctioning due to icing. (6) Where duplicate air-speed indicators are required, their respective pitot tubes shall be spaced apart to avoid damage to both tubes in the event of a collision with a bird. (b) Static air vent and pressure altimeter systems. (1) All instruments provided with static air case connections shall be vented to the outside atmosphere through an appropriate piping system. (2) The vent(s) shall be so located on the airplane that its orifices will be least affected by air flow variation, moisture, or other foreign matter. (3) The installation shall be such that the system will be air-tight, except for the vent into the atmosphere. (4) Pressure altimeters shall be of an approved type and shall be calibrated to indicate pressure altitude in standard atmosphere with a minimum practicable instrument calibration error when the corresponding static pressures are applied to the instrument. (5) The design and installation of the altimeter system shall be such that the error in indicated pressure altitude at sea level in standard atmosphere, excluding instrument calibration error, does not result in a value more than the ±30 feet per 100 knots in speed for the appropriate configuration in the speed range between 1.3 Vs. (flaps extended) and 1.8 V11 (flaps retracted), except that the error need not be less than ±30 feet. (c) Magnetic direction indicator. (1) The magnetic direction indicator shall be installed so that its accuracy will not be excessively affected by the airplane's vibration or magnetic fields of a permanent or transient nature. (2) After the magnetic direction indicator has been compensated, the calibration shall be such that the deviation in level flight does not exceed ±10° on any heading. (3) A calibration placard shall be provided as specified in § 4b.733. (d) Automatic pilot system. If an automatic pilot system is installed, it shall be of an approved type, and the following shall be applicable: (1) The system shall be so designed that the automatic pilot can be quickly and positively disengaged by the human pilots to prevent it from interfering with their control of the airplane. (2) A means shall be provided to indicate readily to the pilot the alignment of the actuating device in relation to the control system which it operates, except when automatic synchronization is provided. (3) The manually operated control(s) for the system's normal operation shall be readily accessible to the pilots. The quick release (emergency) controls shall be installed on both the pilots' control wheels, on the side of the wheel opposite from the throttles. Attitude controls shall operate in the same plane and sense of motion as specified for the cockpit controls in § 4b.353 (b) and Figure 4b-16. The direction of motion shall be plainly indicated on or adjacent to each control. (4) The automatic pilot system shall be of such design and so adjusted that, within the range of adjustment available to the human pilot, it cannot produce hazardous loads on the airplane or create hazardous deviations in the flight path under any conditions of flight appropriate to its use either during normal operation or in the event of malfunctioning, assuming that corrective action is initiated within a reasonable period of time. (5) When the automatic pilot integrates signals from auxiliary controls or furnishes signals for operation of other equipment, positive interlocks and sequencing of engagement shall be provided to preclude improper operation. Protection against adverse interaction of integrated components resulting from a malfunction shall be provided. (e) Instruments utilizing a power supply. The following shall apply to each instrument required in § 4b.603 (f), (g), and (h) which utilizes a power supply: (1) Each instrument shall have a visual type of power failure indicating means, integral with or located adjacent to the instrument, to indicate when adequate power is not being supplied to the instrument (see note) to sustain proper instrument performance. The power shall be sensed at or near the point where power enters the instrument. For electric instruments power shall be deemed adequate when voltage is between approved limits. (2) Each instrument shall be provided with two independent sources of power and a means of selecting either power source. When duplicate independent instruments are installed, power source selection need not be provided if each instrument has an independent power source. (3) The installation and power supply system shall be such that failure of one instrument, or the energy supply from one source, or a fault in any part of the power distribution system, will not interfere with the proper supply of energy from the other source. (See also §§ 4b.606 (c) and 4b.623.) NOTE: The word "instrument" as used herein includes those devices which are physically contained in one unit and those devices which are composed of two or more physically separate units or components connected together; such as a remote indicating gyroscopic direction indicator which includes a magnetic sensing element, a gyroscopic unit, an amplifier, and an indicator connected together. (f) Duplicate instrument systems. If duplicate flight instruments are required by the operating parts of the Civil Air Regulations (see note under § 4b.610), the operating system for a duplicate instrument shall be completely independent of the operating system for the duplicated instrument. Additional instruments shall not be connected to the first pilot system. If additional instruments are connected to the other system, provision shall be made to disconnect or isolate in flight such additional instruments. [15 F. R. 3543, June 8, 1950, as amended by Amdt. 4b-6, 17 F. R. 1098, Feb. 5, 1952; Amdt. 4b-8, 18 F. R. 2216, Apr. 18, 1953; Amdt. 4b-2, 20 F.R. 5308, July 26, 1955; Amdt. 4b-6, 22 FR. 5566, July 16, 1957; Amdt. 4b-8, 28 F.R. 2591, Apr. 19, 1958; Amdt. 4b-11, 24 F.R. 7071, Sept. 1, 1959] § 4b.612-1 Air-speed indicating system calibration (FAA policies which apply to § 4b.612(a)). (a) Methods. Unless a calibrated referenced airspeed system is provided, the airplane's system should be calibrated throughout as wide a range as necessary to cover the intended flight tests. The tests in paragraph (c) of this section are for the purpose of showing compliance with § 4b.612(a) and not intended to cover the speed range of the flight tests. If an alternate air-speed indicating system is provided, it should also be calibrated. The airspeed indicating system should be calibrated in accordance with the following methods: (1) The tests should be conducted in stabilized flight at air speeds throughout the speed range for the airplane configurations to be tested. The airplane's air-speed indicator should be calibrated against a reference air-speed system or against a ground speed course. (2) A reference air-speed system should consist of either of the following: (i) An air-speed impact pressure and static pressure measurement device or devices that are free from error due to airplane angular changes relative to the direction of the free stream or due to slipstream variation resulting from changes in airplane configuration or power. In addition the device or devices should have a known calibration error when located in the free stream, or (ii) Any other acceptable air-speed calibration method, for example, the altimeter method of air-speed calibration. However, when using the altimeter method care should be exercised to measure the airplane's altitude accurately-especially at speeds below 125 mph. (3) When establishing the airplane's true air speed by means of the ground speed course, flight between the two reference points should be made at constant air speed in two successive runs in opposite directions to eliminate the effect of wind. The runs should be made only in stable wind. The time to make the runs should be obtained by means of some calibrated device. The speed runs should not be made nearer the ground surface than a wing span's length. (4) If an alternate system is provided it may be calibrated against either the reference system or the airplane's system. (b) Configuration. Air speed calibration tests should be conducted in the configurations that follow: Weight-Between maximum take-off and maximum landing. C. G. position-Optional. Wing flaps and landing gear retracted. Engines Optional power. (c) Test procedure and required data. Any one or any desired combination of the procedures in subparagraphs (1) through (3) of this paragraph may be used for calibrating the air-speed instrument. The air-speed should be measured or determined simultaneously from the airplane's and the reference system during stabilized runs for at least five speeds spaced throughout the speed range, the lowest not to exceed 1.3 V11. The highest speed should not exceed VNO, placard speed, or speed in level flight using maximum continuous power, whichever is lower. The speed spread between the test speeds should be limited to 10 mph from 1.3 V., to 1.6 V11 or placard speed, and 30 mph from 1.6 V., to VNo. 1 (1) Speed course. The air-speed and altitude should be stabilized before entering the speed course. Constant air speed should be maintained during each run. The runs should be made in both directions for each speed over the speed course. The following data should be recorded: Time of day at beginning of run. Pressure altitude. Ambient air temperature. Air speed at several intervals during run. Landing gear position. (2) Reference air-speed system. Stabilized runs at the test speeds listed in this paragraph should be made. The air speed from the airplane's air-speed system and the reference air-speed system should be read simultaneously. The following data should be recorded: Ambient air temperature. (3) Other acceptable air-speed calibration methods. Stabilized flight runs at the test speeds should be made and the necessary data recorded to establish the airplane's air-speed system error and the configuration of the airplane. [Supp. 24, 19 F. R. 4466, July 20, 1954, as amended by Supp. 25, 20 F. R. 2280, Apr. 8, 1955; Supp. 26, 20 F. R. 6677, Sept. 10, 1955] § 4b.612-2 Static air vent system (FAA policies which apply to § 4b.612(b)). (a) If the altimeter installation is of the pressure type its operation will be affected by any error that exists in the static air pressure. Since the accuracy of the altimeter is of utmost importance the static air vent system should be cali brated. If separate or alternate vent systems are employed for the altimeter and airspeed indicator, separate calibrations are required. Where the altimeter, rate of climb indicator, and air-speed indicators are vented to the same static systems, the altimeter calibration may be made in conjunction with the air-speed calibrations. (b) The theoretical relationship between air-speed error and altimeter error is given in Figure 4 so that an altimeter calibration may be derived from the airspeed calibration if both use the same static vent provided that the total head installation is such as to provide true readings over the range of angles involved. (Note: See Figure 4, infra). [Supp. 24, 19 F.R. 4466, July 20, 1954, as amended by Supp. 32, 22 F.R. 5793, July 20, 1957] 70 |