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12 Cards in this Set
- Front
- Back
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what is OHM' s law
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The current in an electrical circuit is directly proportional to the electromotive force in the circuit, and inversely proportional to the resistance. The most common form of the law is E = IR, where E is the electromotive force or voltage (volts) across the circuit, I is the current (amperes) flowing in the circuit, and R is the resistance (ohms) of the circuit.
Also written as: One volt [of electromotive force] is attained as one ampere [of current] passes through one ohm [of resistance.] |
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b. Thermocouple
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A junction of two dissimilar metals that produces a voltage when heated
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c. Frequency
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The number of complete cycles per second existing in any form of wave motion, such as the number of cycles per second of alternating current, light, radio waves, etc. More commonly expressed as `hertz' (Hz).
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.2 Describe alternating current (ac) and direct current (dc).
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A/C - A flow of electric charge that reverses its direction periodically. D/C - An electric current that flows in one direction only.
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.3 State the output of the MH-60S aircraft generator in reference to the following parameters
Voltage Phase Frequency |
Voltage - 115/200 VAC (volts alternating current)
Phase - Three Phase (A,B,C) Frequency - 400 Hz |
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.4 State the purpose and location of the aircraft battery
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Is located in the copilot seat well and provides a primary source of power for APU starting
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Describe the differences between the following types of tests
Voltage Continuity |
a. Continuity [p. 2-12] - Indicates if the circuit is complete or continuous.
b. Voltage [p. 2-13] - Isolates malfunctions to major components and to maintain subassemblies, units, and circuits |
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6 Discuss the purpose of the following test equipment
Digital multimeter Time Domain Reflectometer (TDR)- |
a. Digital multimeter - An accurate, reliable measuring instrument used at the organizational, intermediate, and depot levels of maintenance. Measures ac and dc voltages to a maximum of 1,000 volts and resistance to 10 megohms.
b. Time Domain Reflectometer (TDR)- A measuring instrument that can find the distance to a discontinuity by measuring the time required for the pulse to travel down the line to the reflecting impedance and back to the monitoring oscilloscope. |
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Briefly describe the pitot static system
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The pitot-static system provides pressure for the operation of the differential pressure instruments: the barometric altimeters and airspeed indicators. Two pitot tubes are mounted above the cockpit, forward of the hydraulics bay. Two static ports are located on the fuselage sides, aft and under each cockpit door. Pitot pressure is supplied from the pitot tubes to the airspeed indicator, airspeed and air data transducers, and pitot-drain caps. To obtain a difference in the pressure for operation of the barometric differential pressure instruments, static air pressure (atmosphere) is supplied through the static ports (located on the pitot-static tubes) to the altimeter, airspeed indicator, airspeed and air data transducers and static drain caps.
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State the difference between the barometric and radar altimeter.
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Barometric - Uses static pressure to indicate altitude above sea level.
Radar - Uses radio frequency (RF) echoes to determine altitude above ground level. |
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Explain the operating characteristics of the Emergency Locator Transmitter
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Consists of an emergency locator transmitter (portable and aircraft-mounted), an antenna, and an interconnecting coaxial cable for aircraft antenna feed. The locator transmitter is on the control-enclosure bulkhead behind the pilot's seat. The aircraft antenna on the tail transition section is connected to the transmitter by a coaxial cable routed through the cabin. The transmitter is a self-contained, dry cell, battery-operated unit. When turned on by and ON/OFF/ARM switch, it simultaneously transmits a distress signal on the international distress frequencies of 121.5 MHz and 243.0 MHz. The distress signal may travel as far as 100 miles, at a search altitude of about 10,000 feet. When the selector switch is placed to ARM, the transmitter will automatically activate upon an impact force of 5 g's. With the switch on, the transmitter is activated. The signal emitted by the transmitter, when activated, is a tone that varies form 1600 Hz to 300 Hz, at a rate of 2 to 3 times per second.
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Define the following acronyms
EGI UHF VHF MFD HUD CSC DALS IFF AFCS |
a. EGI [p. 63] - Embedded Global Positioning System Inertial Navigation System
b. UHF [p. 68] - Ultra High Frequency c. VHF [p. 68] - Very High Frequency d. MFD [p. 66] - Multifunction Display e. HUD [p. 64] - Heads Up Display f. CSC [p. 63] - Communication System Controller g. DALS [p. 63] - Downed Aircrew Locator System h. IFF [p. 65] - Identification Friend or Foe i. AFCS [p. 61] - Automatic Flight Control System |
