WEATHER RADAR (COLLINS WXR-2100) Flashcards
Which part of a Thunderstorm is the most reflective part?
The lower part below the freezing level, above it ice crystals starts to form which are less reflective
How far out, in NM can the Collins WXR-2100 scan?
320 NM
320 NM ahead of an aircraft, how much of an altitude drop (in ft) does the earths curvature cause?
65000 ft
How often is the WX Radar image updated on the Collins WXR-2100?
Every 4 seconds
How does the MCS (Multi Scan System) work on the Collins WXR-2100?
Upper beam detects intermediate weather
Lower beam detects short range and long range weather due to curvature of the earth
What is GCS on the Collins WXR-2100?
Ground Clutter Supression
Can the pilots have different gain and tilt settings on their respective ND:s?
No, its single function
How is the tilt value displayed on the WX radar calculated?
It is the average of the upper and lower beam
Split is higher at lower levels and split decreases as altitude increases
Is tilt operation available during multi scan operation?
No, it is the average of the lower and upper beam
Tilt is only available in MAN mode
Up to what distance can turbulence be detected on the WX radar?
40 nm
What is needed for the turbulence function on the WX radar to show areas of turbulence?
At least some precipitation with velocity changes.
It cannot detect clear air turbulence
Is turbulence displayed in MAP mode on the WX radar?
No
What is the reason you would decrease gain to min on a WX radar?
If you decrease it to min and a cell is still red it means that it most likely is severe
Do you need to change the gain when climbing into colder air?
No, gain is temperature adjusted
What is the PAC alert function on the WX radar?
“Path Attenuation Compensation”
PAC displays a yellow arc on the outermost scale to warn the pilots of the attenuated condition
PAC shows displays up to 80 nm ahead if the aircraft
Is only available in CAL mode
What is “Overflight Protection” for the WX Radar?
As the aircraft gets closer to a storm the radar tends to overscan and not show the middle part, meaning that severe weather might not show up.
The system keeps the lower levels in memory to display the middle layers and gives a more accurate picture
Is the GCS function active during manual operation of the weather radar?
No
In MAN mode, what is a good radar tilt setting below 10000 ft?
Between +2 to +7 deg with +5 deg being a good compromise
In MAN radar mode, why would 7 deg setting be not such a good idea?
It scans along the path of the aircraft and might miss cells below the path
In MAN radar mode, on descent, how would you operate the tilt?
Start with 2 deg below 10000 ft and then increase it to 5 deg
How quickly can a thunderstorm rise, in ft/min?
Up to 6000 ft/min
What does ragged edges of a thunderstorm cell on the WX radar display indicate?
Potential shear condition
What does a steep gradient change of color on a WX radar display indicate?
Significant convective activity or turbulence
What does “fingers” and “hooks” indicate on a WX radar display?
Indicates shear and turbulence
Increase avoidance distance by 50 %
What does the different colors on the WX radar screen indicate in terms of rain fall in mm/hr?
Black = 0 - 0,76 mm/hr
Green = 0,76 - 3.81 mm/hr
Yellow = 3,81 - 12.7 mm/hr
Red = 12.7 - and greater
Magenta = More than 5 m/sec wind velocity
What is the STC function on the WX radar?
“Sensitivity Time Control”
It compensates for beam attenuation for cells up to 80 nm
More distant cells have more energy on the target than do cells closer
Solves the problem that cells look bigger the closer they get
What is the “Associated Threat Assessment” on the WX radar? How is it displayed?
Displayed by red Dots
Indicates areas of possible hail, lightning and convective activity
What is the “Predictive Overflight Function on the WX radar? How is it displayed?
It shows areas of rapidly growing cells
Indicated by a red dotted area with red borders
What is the REACT system on the WX radar display? How is it displayed?
Shows area of possible attenuation
Indicated by purple bend lines extending outwards
How is predictive lightning indicated on the WX radar display?
A big yellow z like symbol
How is hail indicated on the WX radar display?
By a yellow triangle
How should we operate the WX radar before take-off?
Set Multiscan to MAN mode and set 15 deg up to scan weather
On take-off, with the WX radar mode in AUTO, how does the MCS beams scan?
Lower beam is set to 3 deg and upper is set to 7 deg with the displayed average being 5 deg
What is the best range to have on your ND so scan for weather?
80 nm
What is the technique for setting the tilt on the WX radar from take-off to climb?
GND = Tilt +4 deg
5000 ft = +3
10000 ft = +2
15000 ft = +1
20000 ft = +0
25000 ft = -0,5
30000 ft = -1,0
35000 ft = -1,5
40000 ft = -2,0
What is the minimum distance ahead of a storm cell do you have to start changing course?
Min 40 nm
If within 40 nm you will hit it
