Nav 1 Flashcards
What is standard air pressure and temperature at sea level?
15 Degrees and 1013.2 Mb
What type of pressure is picked up by a ‘Pitot tube’ ?
Ram Air Pressure
What are the components of a ‘Pressure Altimeter’ ?
Aneroid chamber that inside has 2 evacuated bellows or a diaphragm
At the Barosetting QNH, the altimeter shows …………. at landing?
Altitude above sea level
At the Barosetting QFE, the altimeter shows …………. at landing?
0 (Field Elevation)
During cruise the altimeter setting is ………. And shows the ………..?
QNE and Flight Level
An ASI in a pressurised aircraft, a leak in the static-tube and in the pitot tube will cause?
Under Reading
What is IAS and CAS and what is the difference?
Uncorrected reading of an Altimeter is IAS and airspeed taking into account instrument error and airflow error is calibrated airspeed.
What is TAS?
True Airspeed is the same as CAS at standard conditions. TAS takes into account temperature and altitude.
What is GS?
Ground Speed represents the actual speed on the airplane over the ground and is adjusted for wind.
What is Vmo and Mmo and for what are they used?
Maximum operating limit speeds that should not be exceeded. Pilots are alerted if the limit is exceeded.
What are the inputs to an Air Data Computer?
Discretes, Total Temp, Pitot and Static pressures, baro setting, AOA
How does an ADC converts pneumatic pressure into electrical data?
Through an Oscillator or transducer that outputs an analogue signal then through an ADC for a digital output.
Name the different types of Gyros?
Vertical, Directional, Rate, Rate Integrating and Laser
What is a vertical gyro used for?
Measuring pitch and roll (Axle points to earth)
Where is maximum apparent drift for a directional and vertical gyro?
Both 15 degrees, directional at the pole and vertical and the Equator
How is the vertical Gyro vertically erected?
Electrically using a torquer. A gravity sensing liquid.
Name the vertical gyros angle outputs?
85 degrees pitch and 360 degrees roll.
The Directional Gyro will drift due to?
Precession Errors (Apparent Drift)
What instruments is a rate gyro used in?
Turn and slip indicator and turn co-ordinator.
What does the bank angle of a correct flown turn depend on?
Aircraft Speed
What is sensed by laser Gyros and where are they used?
Angular Rate and they are used in IRS systems.
What is variation and what is the reason for it?
The error between the geographic poles and magnetic poles. Aeronautical charts are marked with lines of equal variation, isogonic lines.
When is a Magnet compass reading correct?
When the aircraft is horizontal, No acceleration and the reading is corrected with the deviation card.
Where is the flux valves stored and for what is it used?
At a point where there in minimal magnetic interference and it electronically valves the earths electronic field to sense the direction of magnetic north.
What is the advantage of a gyro stabilized compass system over a compass system?
It gives the directional gyro all the advantages of a magnetic compass without its most disturbing faults.
What is the build-up of a flux valve?
Highly Permeable Iron Frame made from a segmented circle with 3 legs radiating out from its centre. Excitation coil in the centre and pick up coils around each of the 3 legs.
Why are some compasses equipped with a synchronizing knob?
To fast synchronise the compass
Newer compass systems will not use flux valves anymore, how will they determine magnetic heading?
IRUs by using the true heading, Magnetic variations are stored in the IRS memory.
What error is inherent in magnetic compasses?
Deviation
Explain Latitude and Longitude?
Latitude is N/S and Longitude is E/W
What are the Co-Ordinates of Zurich Airport?
N47 Deg 26,7
E8 Deg 34,0
What are the components inside an INS system?
Mode Selector Unit, CDU, INU, HSI, Battery Unit
Newer systems use strap down technology, why is this?
Gyros and accelerometers are mounted solidly to the system chassis which in turn is mounted to the aircraft.
The ADF shows the direction towards a?
Non directional and broardcasting ground station
Name the Localiser frequency band?
108.10 -111.95 all odd 1/10 Mhz steps (even steps are reserved for VOR)
What is the glide path frequency band?
330 Mhz roughly
How is the ILS receiver tuned?
Via the control panel or the MCDU
What is the operational frequency of RA?
4.3 Ghz
What is the purpose of GPWS?
Aural warnings are used in the GPWS when the aircraft is in a dangerous position relative to ground
What does EGPWS incorporate?
Terrain and display functions using an internal terrain database.
The space segment of GPS contains how many satellites in how many orbits?
24 (21 active and 3 spare) in 6 orbits
How long does it take a GPS satellite to orbit the earth and at what altitude?
12 hours and 11,000 Nm
In GPS what is the control segment comprised of?
4 monitor stations and 1 master control station
What type of clocks are used in satelites, and how many?
Atomic clocks x 4
GPS transmits 2 signals (P) precision mode and (C/A) course/acquisition mode who uses what?
(P) precision mode is used for the military and (C/A) course/acquisition mode used by civilians.
What is the purpose of the WX Radar?
To detect and display severe weather areas so the pilot can avoid.
What are the possible WX Modes?
Map (ground mapping), WX (radar in normal range), WX/TURB Turbulant Areas shown in magenta within 40 NM range.
The turbulence radar mode is based on what principle?
Pulse waveform show the echo frequency from the transmitted pulse .
What is the radiated power of Wx?
125W to 65 Kw
What is the purpose of an attitude signal to the antenna in a weather radar system?
Antenna Stabilization
What are the dangers when operating the weather radar?
Damage to human cells and ignition of a combustible material.
What is the purpose of the DME system?
Provides a digital read out of slant range distance from a selected ground station.
What is the frequency range of DME?
around 1025 Mhz to 1150 Mhz
The frequency of a ground transmitter in DME is always …… Mhz above or below the interrogator frequency?
63
What does JITTERING mean in DME?
Allows the interrogator to find its own pulses.
DME systems’ have a built in delay of?
50 microseconds
What are the 3 ATC modes and the information they contain about the aircraft?
A - Identification
C - Altitude
S - Comms Link
What is the time spacing of ATC mode A and mode C?
A - 8 microseconds
C - 21 Microseconds
When is the P2 pulse transmitted in ATC?
2 microseconds after P1
In ATC what are the interrogation and reply frequencies?
1030 and 1090 Mhz
What is the advantage of mode S over mode A?
???
What does an FMS do?
compares a pilot selected flight plan with the actual horizontal and vertical aircraft position
What gives the AFS steering and thrust commands?
The FMS
Where is the FMS flight plan selected?
On the CDU
