BEACON LIGHTS - DESCRIPTION AND OPERATION
1. General (Fig. 1)
A. Red flashing beacon (anticollision) lights are mounted on the top and he bottom of the airplane fuselage aft of the wing leading edge. The anticollision light switch on the pilot's forward overhead panel provides control.
2. Upper Beacon Light (Fig. 2)
A. The upper beacon light is mounted through a cutout in the top of the fuselage. The beacon light installation consists of three basic components. These are the mounting plate that is permanently attached to the airplane structure; the lens, gasket, and retaining ring which are installed from the topside of the airplane; and the light assembly that is installed from the inside of the airplane.
(1) The beacon light assembly consists of a xenon arc flashtube (lamp) encircling a parabolic reflector. The reflector directs the light beam horizontally. The reflector and lamp are mounted to a transistorized unit containing a timing circuit and a power supply. The timing circuit controls the flash rate at approximately one flash per second. The light assembly is removed from the inside of the airplane for relamping or replacement by lowering a ceiling panel, loosening four mounting screws, pulling the light assembly and disconnecting the electrical wiring.
B. The 115-volt ac transfer bus No. 1 supplies electrical power for light operation through the ANTICOLLISION LT - UPPER circuit breaker on the P18 circuit breaker panel.
3. Lower Beacon Light
A. There are two types of lower beacon light installations. One is similar to the upper beacon light. The other uses a flange assembly onto which the lens is fastened with a retainer band. The light is mounted through a cutout in the bottom of the fuselage. A pan inside the fuselage provides a receiving area for the light assembly and fuel vapor isolation. The light assembly may be removed by removing mounting screws, pulling light assembly and disconnecting electrical wiring.
B. The 115-volt ac transfer bus No. 2 supplies electrical power through the ANTICOLLISION LT - LOWER circuit breaker on the P18 circuit breaker panel.
503
May 15/79 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 33-44-0 Page 1
Beacon Light Equipment Location 503
33-44-0 Figure 1 May 15/79
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
503 Beacon Lights Simplified Schematic
Aug 15/76 Figure 2 33-44-0
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.
BEACON LIGHTS – TROUBLE SHOOTING
1. General
A. Trouble shooting the beacon lights is best accomplished during Adjustment/Test (33-44-0). Trouble shooting requires that power be available and appropriate circuit breakers be closed.
B. Trouble shooting procedures are based on the assumption that wiring is OK and electrical power is available. If the corrective action in the procedure does not correct the problem, check the wiring using the wiring diagram.
WARNING: DO NOT LOOK DIRECTLY AT STROBE LIGHT BEACON FROM CLOSE RANGE. LIGHT FLASHES MAY CAUSE MOMENTARY VISION IMPAIRMENT.
2. Beacon Light Trouble Shooting Chart (Xenon Arc Strobe Light)
TROUBLE PROBABLE CAUSE ISOLATION PROCEDURE REMEDY
Light is inoperative Light assembly defective or switch is defective Faulty step-up transformer (airplanes with 28V AC power source) Replace light assembly. If still inoperative, replace switch Check output of transformer for 115V AC. If low, replace transformer Replace light assembly. Replace switchReplace transformer
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