Mock Exam Flashcards
State the indication of aircraft Heading, Track, and Drift shown on the Horizontal Situation Indicator (HSI).
Heading = 225°
Track = 239°
Drift = +14° / 14° Starboard
An aircraft is flying on a track of 270° at a groundspeed of 650kts for 3 hours. Its starting position was 47°00’N 004°00’E. Calculate its new position.
New position: 47°00’N, 043°39’W
Identify one advantage and two disadvantages of a closed-loop system.
Advantage: Self-adjusting
Disadvantages: More expensive, Slower, More complex
Name four other types of transducers that use the ‘inductive principle’ other than the E & I bar.
Linear Variable Differential Transformer (LVDT), Control Synchro, Torque Synchro, Differential Synchro, Resolver Synchro
Name three properties required to be classed as a servomechanism.
Error Actuation, Power Amplification, Continuous Operation, Follow-up properties
From the diagram of the Electronic HSI (EHSI), identify the item in the yellow rectangle (VS470) and describe an advantage of using the EHSI over a conventional HSI.
VS470 indicates Vertical Speed (rate of climb/dive) at 470 ft/min.
Advantage: The display is ‘software driven,’ allowing usage across different aircraft by changing the software component.
Describe the term maintenance mode in relation to Multi-Function Displays (MFD).
Built-In-Test (BIT) & BIT Equipment (BITE) detect failures in the system and aid fault finding in the aircraft.
Identify the symbol labeled ‘d & f’ on the HUD diagram and describe one method used to produce symbology on the HUD.
Symbol d = Airspeed
Symbol f = Angle of Attack
Method: Cursive scan or Raster scan
Explain the primary function of an Inertial Navigation System (INS).
Provides continuous latitude & longitude positional information of the aircraft.
Identify components 1 and 2 from the inertial navigation diagram and state what information is obtained at point 3.
Component 1 = 1st Integrator
Component 2 = 2nd Integrator
Point 3 = Aircraft Velocity
Identify one method used by a strapdown INS to update positional information.
Position Fixing: when the aircraft fly’s over a known point and updates the ins output with the latitude and longitude of a fixed position.
Position Error Compensation: employs a recursive software called a kalman filter which carries out statistical analysis to predict future errors from the ins
Identify the problem that early ring laser gyros suffered from and how it was corrected.
Low input rates of rotation caused laser beams to lock together.
Correction: Using a dither motor or different frequencies for each beam.
An aircraft is approaching the runway and the ILS is receiving 90Hz on the Localiser and 150Hz on the Glideslope. What commands are provided to the pilot?
90Hz Localiser = Fly Right signal
150Hz Glideslope = Fly Up signal
Explain the warnings that are given by a GPWS.
Audio: Tone/voice message (‘Terrain-Terrain’)
Visual: Flashing RED light or ‘Breakaway cross’ on HUD
State the scan rates for both Azimuth and Elevation beam sweeps and explain why Elevation is higher than Azimuth.
Elevation: 39Hz
Azimuth: 13Hz
Reason: Elevation control is more responsive due to height & glideslope changes.
Excluding Bearing information, identify two other types of information provided by VOR.
Morse code identifier signal, Fly Left/Right signals, Fly To/From indications
Using the TACAN diagram, explain the purpose of the Azimuth, Identity, and Range Chain blocks.
Azimuth: Converts course and fine bearing of the beacon position, wrt magnetic north, for the HSI/HUD
Identity: Processes pulse into a morse code identifier for the pilots headset
Range: Converts transponder signal into slant range distance from the beacon
What is the purpose of the DME system?
Provides slant range distance from the beacon.
Excluding ‘Almanac data,’ identify two other types of GPS information and which segment uses it.
Pseudo Random Code (PRC) for the USER segment
Ephemeris data for the SPACE segment
Explain the ‘memory’ state in a pulsed Rad Alt system.
Stores previous height reading for 0.2s when signal is lost. If no signal returns, enters search mode.
Identify three disadvantages of using a ‘single beam’ Doppler.
Transmitter instabilities, Pitch & vertical errors, Groundspeed errors.
Identify and describe the method used to reduce the response time of an AFCS.
Phase Advance: Mixes in-phase and phase advance signals for a composite waveform.
Explain the effect of moving the approach switch in an AFCS system.
Before switching: No value stored.
After switching: System captures ILS signals to generate a flight path error signal for control surfaces.
Give two examples of safety devices used with Autopilot systems.
Instinctive cut-out (ICO), Rate/Control limiters, Torque devices, Built-in-test (BIT)
Excluding ‘weight and space saving,’ name two other advantages of Fly-by-Wire over mechanical systems.
No friction/backlash in gears, Battle damage resistance, Instant response, Spin prevention
Describe ‘Air data scheduling’ with respect to Fly-by-Wire.
Air Data Computer (ADC) provides height and speed data to modify system response accordingly.
Explain the difference between duplex and quadruplex Fly-by-Wire systems.
Duplex has two channels, quadruplex has four.
Duplex fails if any channel is lost, quadruplex can lose two channels and still function.
