Switching Off weather radar
Join Date: Jan 2001
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At the previous airline I worked at, on line up WX radar on; exit active WXR off. Interestingly even at an airline which had moved onto multiscan weather radar, there were many pilots who didn't understand it / didn't know how to use it, therefore didn't trust it. We also used to test the weather radar as part of the pre-flight scan (med based airline).
At the airline I work for now, we switch the radar on and off as necessary. I still meet captains who think that the reflected beam off another aircraft will be enough to fry your nuts - power output has gone down so much on modern units that you could theoretically quite safely (as far as we are told) stand more than a few feet away from the business end of the WX radar while it is on. I suspect WX radar is a poorly understood area for many pilots - myself included, although at least I read the manual.
I know a crew who using my latest airlines cultural approach to WX radar flew into a CB while not monitoring things outside of the window; but monitoring EFIS without WXR on...
At the airline I work for now, we switch the radar on and off as necessary. I still meet captains who think that the reflected beam off another aircraft will be enough to fry your nuts - power output has gone down so much on modern units that you could theoretically quite safely (as far as we are told) stand more than a few feet away from the business end of the WX radar while it is on. I suspect WX radar is a poorly understood area for many pilots - myself included, although at least I read the manual.
I know a crew who using my latest airlines cultural approach to WX radar flew into a CB while not monitoring things outside of the window; but monitoring EFIS without WXR on...
Join Date: Oct 2001
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Situational awareness is the key. During winter in Europe, the convective activity can be zero over a vast area. Why turn on the radar, when cruizing 35900' over a 100' layer of fog for two hours?
When in doubt, it definitely should be switched on! And there are tropical locations where it has to be used every single day.
When in doubt, it definitely should be switched on! And there are tropical locations where it has to be used every single day.
Join Date: May 2002
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With the old type of WX radar, the dish was stabilised when switched to stdby or on. However it was not stabilised when switched off.
There was a lot of wear and tear to the dish mounts etc.,on taxi, etc., with the dish flopping up and down and around. IIRC.
There was a lot of wear and tear to the dish mounts etc.,on taxi, etc., with the dish flopping up and down and around. IIRC.
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Having started long distance flights before radar was fitted, perhaps I appreciate it's benefits more than most.
I generally kept it on crossing the pond and the Med even though the sky was clear of cloud, to detectional gross navigational errors.
I remember the story of the captain who picked up what he thought must be a large ice mass floating in the atlantic. When pushed the navigator suggested checking a VOR station that "couldn't possibly be in range".
It was.
...and the lage ice mass was for real. The one that covers Greenland!
I generally kept it on crossing the pond and the Med even though the sky was clear of cloud, to detectional gross navigational errors.
I remember the story of the captain who picked up what he thought must be a large ice mass floating in the atlantic. When pushed the navigator suggested checking a VOR station that "couldn't possibly be in range".
It was.
...and the lage ice mass was for real. The one that covers Greenland!
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...to detectional gross navigational errors.
Join Date: Jul 1999
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I remember the story of the captain who picked up what he thought must be a large ice mass floating in the atlantic. When pushed the navigator suggested checking a VOR station that "couldn't possibly be in range".
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From a maintenance perspective, weather radar formerly needed to be operated regularly to protect the magnetron; failure to operate em the radar regularly would result in the loss and replacement of the most expensive component.
Today with solid state systems that do not have those problems, turning off the radar won't harm the system with respect to not energizing the magnetron. However, gyro stabilization and power to the gyro platform does extend life. It's hard on the motor, gimbal mount, and other components to bounce along in turbulence without being stabilized and protected with the system energized...wear is minimized by having power to the radar unit (at least in standby).
So far as mean time between failures, the life of a radar unit is so extensive that failures are rare anyway; the most common failure points aren't in the radar, but in the mechanical components...and these are protected when the system is on...not worn out or brought closer to failure.
This may seem counter-intuitive. However, with a gyrostabilized radar platform, you can think of it in a similiar manner to a simple air-driven gyro on a light airplane. Sitting in the tie-downs on the ramp is harder on the airplane, and does more to damage the instruments, than flying with the gyro spinning. Why? Because as the airplane bounces and rocks in the wind on the ground, the ruby bearings and needles in the instrument wear concentric patterns, and lead to precession over time...a gyro can wear out just sitting on the ramp not turning. In the case of the radar unit, when it's not stabilized and protected by an energized system, wear increases, and the frequency with which mechanical problems will develop, increases.
True enough, the mean time between failures for the radar systems in general, with respect to the electronics, may increase, but the trouble components, particularly dish hardware, decreases...and this is the highest maintenance item. While it's no longer necessary with modern systems to energize the magnetron to keep it from permenantly failing, it's still benificial to run the radar.
With older radar, of course, failure to run the radar will result in a drastically reduced life of the magnetron.
Today with solid state systems that do not have those problems, turning off the radar won't harm the system with respect to not energizing the magnetron. However, gyro stabilization and power to the gyro platform does extend life. It's hard on the motor, gimbal mount, and other components to bounce along in turbulence without being stabilized and protected with the system energized...wear is minimized by having power to the radar unit (at least in standby).
So far as mean time between failures, the life of a radar unit is so extensive that failures are rare anyway; the most common failure points aren't in the radar, but in the mechanical components...and these are protected when the system is on...not worn out or brought closer to failure.
This may seem counter-intuitive. However, with a gyrostabilized radar platform, you can think of it in a similiar manner to a simple air-driven gyro on a light airplane. Sitting in the tie-downs on the ramp is harder on the airplane, and does more to damage the instruments, than flying with the gyro spinning. Why? Because as the airplane bounces and rocks in the wind on the ground, the ruby bearings and needles in the instrument wear concentric patterns, and lead to precession over time...a gyro can wear out just sitting on the ramp not turning. In the case of the radar unit, when it's not stabilized and protected by an energized system, wear increases, and the frequency with which mechanical problems will develop, increases.
True enough, the mean time between failures for the radar systems in general, with respect to the electronics, may increase, but the trouble components, particularly dish hardware, decreases...and this is the highest maintenance item. While it's no longer necessary with modern systems to energize the magnetron to keep it from permenantly failing, it's still benificial to run the radar.
With older radar, of course, failure to run the radar will result in a drastically reduced life of the magnetron.
