203.1.1 Discuss the purpose of the following communication equipment:

a. Public Address System

The public address system enables the pilots and the flightcrew to address the passengers through speakers located in the cabin of the aircraft. Each has a handset that looks like a telephone.

b. Ultra High Frequency (UHF)

Radio frequencies between 225.00 and 399.95 megahertz used in various UHF radios.

c. Very High Frequency (VHF)

Radio frequencies between 116.000 and 149.975 megahertz used in various VHF radios.

d. High Frequency (HF)

Radio frequencies between 2 and 29.50 megahertz used in the HF radio.

a. Inertial Navigation Systems (INS)

Provides navigation and guidance data without reference to ground-based navigation aids. Provides steering guidance, tracking, capture of the signal, and leg transfer signals to the autopilot. It also provides steering commands to the flight directors and true heading, desired track, and track deviation.

b. Tactical Air Navigation (TACAN)

Provides bearing and range up to 300 nautical miles to a selected TACAN facility or to the surface or airborne tacan beacon.

c. Global Positioning System (GPS)

Global Positioning System. Works in conjunction with a minimum of three global satellites to provide exact location in longitude, latitude and attitude. Accurate within 3 to 6 meters.

d. Automatic Direction Finding (ADF)

There are 2 identical ADF systems installed in the aircraft and they receive signals from radio range stations, commercial AM stations, and low-frequency nondirectional navigation aid stations in the 190- to 1750-kilohertz frequency range.

e. Traffic Collision Avoidance System (TCAS)

Traffic Collision Avoidance System. Tells the exact position or location of other aircraft traffic.

a. Voice Recorder

The voice recorder records and preserves all sounds and voice conversations audible on the flight deck and communications heard on either the pilot, copilot, or crewchief headsets. The recorder will record and preserve the last 30 minutes of sounds and communications.

b. Flight Recorder

The flight data recorder is an airborne recorder that provides a record of pressure altitude, indicated airspeed, heading, vertical acceleration with respect to time, and time correlation of communication with Air Traffic Control. The tape provides 300 hours of recording for each side of the tape. The recorder and tape are fireproof, waterproof, and able to withstand unusual shock and vibration.

a. Aircraft Battery

The aircraft has 2 series-connected nickel cadmium 14-volt batteries that provide emergency alternating current (ac) and direct current (dc) power to essential flight instruments and necessary lights and radios in the event of a total loss of ac power. The batteries are also used for power to start the APU and run the refueling system via the emergency inverter when normal ac power is not available.

b. Main alternating current (ac) generator

The voltage output of each generator is controlled by a static adjustable-type voltage regulator set to maintain 115-volts ac output.

The ac power distribution system is divided into two separate systems operating independently of each other, but with crosstie capabilities. The right and left ac generators supply power, through the right and left generator relays, directly to the respective generator buses for distribution. Power from the APU or an external power supply may be routed to either or both generator buses when the respective engine drivin generator is not operating. In the event that either generator shuts down for a fault on that generator bus, the ac crosstie relay will lock open, isolating that bus from the rest of the system. There is a priority control of ac power to the right and left generator buses. The engine driven generators have the highest priority. The APU generator has the next priority, and the external power has the lowest.

a. Strobe lights

Strobe lights are installed on each wingtip. They are used to designate the end of each wingtip.

b. Position lights

The forward position lights consist of a red light on the left (port) wingtip and a green light on the right (starboard) wingtip. They indicate the respective wingtips to other aircraft and ground proximity operations.

c. Nacelle lights

The engine nacelle lights are installed on each side of the fuselage and are provided to visually check the engine nacelles and wing leading edges for icing conditions.

d. Wing landing lights

One retractable wing landing light is installed on the lower surface of each wingtip. They are used to aid in illuminating the landing surface or runway.

e. Nose taxi lights

Two, sealed-beam, fixed position lights are installed on the nose gear assembly. They are used to aid in illuminating the landing surface or runway.

f. Anti-collision lights

The anti-collision lights are installed on the upper and lower fuselage surfaces. They illuminate the aircraft at night and they are illuminated whenever the engines are running.

g. Ground flood lights

A fixed position ground floodlight is installed on each side of the fuselage to provide area lighting for ground servicing and to aid side visibility while taxiing.

h. Downlock lights

These lights are located in the cockpit to indicate if the landing gear is in the down and locked position.

i. Interior/emergency evacuation lights

The emergency evacuation lighting system consists of numerous lights and lighted exit signs located throughout the main cabin, flight compartment, and aft stairway compartment. The lights are powered by 8 rechargable battery packs that supply power for approximately 15 minutes. The lights are controlled by the emergency lights switch located on the overhead switch panel or the emergency lights switch located on the aft flight attendant panel.

Escaping radioactive tritium gas may present a health hazard. If gas is inhaled, seek immediate medical advice.

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