Radar Flashcards
How can the weather radar detect turbulence?
In addition to precipitation, the weather radar can display areas of possible turbulence by measuring precipitation movement.
The weather can not detect clear air turbulence.
What is the maximum range of the weather radar?
The radar automatically scans two different angles to optimize weather detection and minimize ground clutter. When the ground clutter is eliminated, the radar can detect and display weather up to a maximum range of 320 miles.
The radar system is equipped with a 28 inch flat-plate antenna that produces a 3.5 degree beam, which is much narrower than conventional parabolic antennas. As a recommendation, weather evaluation should only be done on returns within 80 NM of the aircraft.
What are the functions of the manual tilt and gain controls of the weather radar?
Manual tilt allows the flight control over the radar beam angle.
Gain is used to increase and decrease the receiver sensitivity.
What is the benefit of having the weather radar communicate with the IRS?
To provide accurate returns the antenna is stabilized to maintain a sweep parallel to the horizon which is provided by the IRS for both the pitch and roll axis.
What is the purpose of the GSC switch?
Radar power is controlled by the SYS switch. Selecting the 1 position allows the system to be powered and display areas of weather. The first two sweeps display both weather and ground returns. Ground clutter is reduced until by the 5th sweep, the initialization is complete and only weather returns are displayed. The Ground Clutter Suppression (GCS) switch can be used to temporarily display ground clutter but is spring loaded to the AUTO position. This switch has no purpose when in the manual mode as ground clutter is always displayed.
What is the purpose of the yellow arc on the ND when using the weather radar?
Due to Path Attenuation or Radar Shadow, the radar may not detect or display any weather that lies beyond an intervening storm. To alert you to areas of attenuation, a yellow alert arc appears at the top of the ND in line with the attenuated area. The alert bar will only be displayed when the GAIN control is set to CAL and intervening weather is within 80 NM of the aircraft.
What is the range of the PWS function?
The weather radar has a predictive windshear function that operates when the PWS switch is in the AUTO position. The system scans the airspace for windshear within a range of 5 NM ahead of the aircraft. The function is available on takeoff and landing as long as one engine is running and the ground speed is greater than 30 knots.
A red and black symbol and two yellow radial lines indicate the predicted windshear area on the ND in ROSE or ARC ND modes.
