H30349
Instantaneous Vertical Speed/Rate of Climb Indicators 501
34-12-0 Figure 3 May 15/81
Page 4
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
4. Altimeters
A. Altimeters are provided for both the captain and first officer. The captain's altimeter is an electric drum-pointer type that receives altitude information from the central air data computer. The altimeter in turn provides altitude information to the altitude alert system. The altitude is displayed in 1000-, 100-, and 20-foot increments on drum counters and in 100- and 20-foot increments by a pointer which reads against a fixed scale. The range of the altimeter is from -1000 to 50,000 feet with altitudes below sea level displayed by the rotating pointer and a NEG flag covering the counter drums. A red warning flag will cover the counter drums in the event of a failure. The failure monitor will show the flag in the event of the following: loss of electrical power to the indicator, loss of flag power from the CADC, excessive servo null voltage, loss of input synchro signal and internal indicator malfunction. A barometric pressure setting knob is provided to adjust the pressure setting which is displayed in both millibars and inches of mercury.
B. The first officer's altimeter is a pneumatic drum-pointer type. The range of the altimeter is from -1000 to 50,000 feet and is displayed in 1000- and 100-foot increments on drum counters and in 100- and 20-foot increments by a pointer which reads against a fixed scale. A barometric pressure setting knob is provided to adjust the pressure setting which is displayed in both millibars and inches of mercury. An instrument vibrator is contained in the altimeter to remove mechanical linkage friction errors.
K84352
5C8 Altimeters
Oct 20/85 Figure 4 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 34-12-0 Page 5
5. Digital Air Data Computer
A. General
(l)
The digital air data computer (DADC) is a solid-state device that uses pitot static pressures and air temperature inputs to compute air data information required by airplane displays and systems. In addition to the above inputs, 115-volt ac and 26-volt ac are provided to a multipin connectors at the rear of the computer.
(2)
The computer is of modular construction and consists of two pressure transducers, 12 plug-in printed circuit cards, a power supply and a chassis assembly. The front panel (Fig. 5) provides two switches for self-test actuation, a self-test indicator light, a fault isolation test connector for off-aircraft trouble shooting and pitot static pressure input connectors. Three electrical connectors mounted on the back of the chassis provide interconnection with the airplane wiring.
(3)
The TEST SELECT switch manually selects built-in test to be performed as follows: FUNCTION - transmits fixed values on all the computer signal output lines. SLEW - sets altitude rate to 600 feet per minute. HOLD - activates hold circuits. FAIL - activates all failure warning flags.
The PUSH TO TEST pushbutton switch initiates the built-in test and the TEST VALID WHEN LIT indicator light comes on within 2 seconds after manually activated test is successfully completed and remains on if there is no failure.
B. Functional Description
(l) The computer uses primary inputs of static pressure (Ps), total pressure (Pt), and air temperature (Ti) to compute air data information. Other inputs required by the computer are power, reference voltages, enabling and command signals, and programmed inputs to inform the computer what airplane it is installed in. The computer contains a microcomputer that operates on the input information to form output parameters of analog and digital voltages representing altitude, airspeed, air temperature, and derivations thereof.
587
34-12-0 Page 6 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. Sep 20/81
K84543
587 Air Data Computer
Feb 15/80 Figure 5 34-12-0
Page 7
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
Air Data Computer System Diagram 5C8
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