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An electric servo altimeter is driven by data from
The air data computer
Altimeter errors due installation?
- Instrument error
- pressure error
- time lag
- Hysteresis error
Pressure error increases as speed increases until?
Speeds around mach one as the bow wave has passed the static source, min error
Hysteresis error is caused by?
imperfect elastic response under extreme conditions of climb and descent
Barometric error hight to low?
low to high?
- high to low = over read
- low to high= under read
With equal pressure in a column of cold air the altimeter will?
In a column of equal pressure in warmer then isa temp the altimeter will?
When a static vent becomes blocked the altimeter will ?
Indicated the height at which the blockage occurred.
True altitude calculation formula?
- calculate PH of aircraft
- determine oat at aircrafts PH
- Computer true alt against oat
- find calibrated alt and read across to true altitude
IAS is a measurement of what?
Dynamic pressure and static pressure making total pressure.
- Instrument error
- Pressure error
- Compressibility error
- Density error
Pressure error is also know as?
Blockage of the pitot system ?
Static leak will cause the ASI to?
A mach-meter incorporates what ?
Altimeter with an airspeed indicator.
Temp sensing is only required when measuring the relationship between Mach and ?
The vsi will indicate? With a static blockage.
When the VSI glass is broken in the event of a blocked static line the altimeter on descent will?
When the VSI glass is broken in the event of a blocked static line the vsi will indicate
IVSI incorporates a?
dash pot or inertia operated pump?
Electronic IVSI us data from?
The inertial navigation systems and are error free.
Direct reading magnetic compass DIP?
Dip is caused by the center of gravity moving away from the center point as the compass is moved from the equator.
Direct reading Magnetic compass turning error.
- ONUS over shoot north under shoot south
- SAND south accelerates north decelerates
Advantages of the direct reading mag compass ?
Simple light weight and no power required
Disadvantages of the direct reading magnetic compass?
Mag deviation, turning and acceleration errors and unstable in turbulence
With a gyroscope apparent drift is ?
Real drift is ?
- Apparent drift is due to earth transport
- Real drift is caused by bearing friction etc
A latitude nut is a compensation for which drift?
Name three components in a RMI
- Flux valve
- electronic motor
The flux valve is located where?
Remotely to reduce magnetic deviation
The main error associated with the RMI is ?
Bootstrapping is when the left RMI and the right HSI is controlled by the ______ flux valve.
Left flux valve.
Normal operation of the RMI will indicate what in the annunciator window ?
Oscillating dot/cross display.
Advantages of the RMI
- Can be slaved to other aircraft systems
- min turning and acceleration errors
- min mag deviation
- stable refrence
Disadvantages of the RMI
Heavy complex and expensive.
A radar altimeter uses _____ transmissions
A radio altimeter uses______ waves
Due to the pulse wave on a radar altimeter the accuracy is only ?
+/- 200ft due to the length of the pulse
Radio altimeters are used for what height indication.
Low level up to 2500 ft
Effect of terrain on radio alt signals, what is the best surface for reliable reading.
Water, sand grass and snow will give a false reading.
Weather radar x band is a form of primary radar which is a _____ transmission on _____ Mhz
SHF transmission on 9350 Mhz
Weather penetration radars use the what band and what frequency ?
C band 5400Mhz
Parabolic antennas create a what radar pattern?
Non pencil shape unlike the flat plate antenna
The pulse length determines what in a weather radar?
The minimum range
Pulse length on a weather radar also determines what?
Range resolution, ability to distinguish different targets at the same altitude and bearing.
Pulse repetition frequency determines the ?
Maximum range of the system
Name 2 type of attenuation the weather radar suffers from?
- Range attenuation due to the signal deterioration proportional to the square of the distance.
- Precipitation attenuation due to weather absorbing the radar and also scattering the signal.
What is azimuth resolution.
Azimuth resolution is the radar inability to distinguish to targets from each other which are less then a beam apart.
Large returns and close contours on a radar screen indicate?
heavy precipitation, turbulence and strong up and down draughts.
Strange shapes on a weather radar may indicate ?
The park position of a weather radar should indicate?
Light sprinkles of ground returns.
Radar display colour ratings.
- Red rain fall is greater the 12mm per hour with 25-100% lightning , severe turbulence
- Yellow rain fall is 4-12mm per hour with a 0-15% of lightning, light to moderate turbulence
- Green rain fall is 0.7-4 mm per hour with light to moderate turbulence