CB tops and manual Gain radar technique may prevent unpleasant surprises
So Teresa, have you had much experience with a "Modern Radar" or only the original black/yellow types in the 9 and 72?
See, I've used the old stuff and the new and the newer new !! and I can tell you we don't use the gain that much anymore, in fact it's not recommended by Honeywell as the rainfall level colours are no longer calibrated to mean much.......Just like maui said above
See, I've used the old stuff and the new and the newer new !! and I can tell you we don't use the gain that much anymore, in fact it's not recommended by Honeywell as the rainfall level colours are no longer calibrated to mean much.......Just like maui said above
The CAL (calibrated) gain setting yields the most accurate correlation
of color levels (black, green, yellow and red) with actual rainfall rates
and their corresponding thunderstorm threat levels.
CAL gain is the recommended gain position for normal operation.
Figure 4-38 shows a radar display with gain set to CAL.
of color levels (black, green, yellow and red) with actual rainfall rates
and their corresponding thunderstorm threat levels.
CAL gain is the recommended gain position for normal operation.
Figure 4-38 shows a radar display with gain set to CAL.
from early seventies
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Maui
"around returns.....or below them" you say.
That seems to imply you are happy to fly over them, well not when I'm flying thank you very much. Another Crew from the company I work for tried that, cleared the highest top they estimated by a minimum of 6000' plus and the result...27 broken limbs down the back.
That seems to imply you are happy to fly over them, well not when I'm flying thank you very much. Another Crew from the company I work for tried that, cleared the highest top they estimated by a minimum of 6000' plus and the result...27 broken limbs down the back.
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Having operated the 737NG radar for the last 8 years, I am in no doubt that the CAL ( calibrated ) gain position is next to useless at best, and positively dangerous at worst - on many occasions in the CAL position, a massive CB can be visually identified ahead, and either nothing shows up on the radar at all, or just a patch of green - it is not until you are within 50 or so miles of the CB that it then changes to yellow and then changes to red as you are about to enter it - with the gain control set to max, the radar appears to pick up the CB as it should - my advice to my FOs for years now has been to always start off with the gain control in max, and once it has picked up the CBs, adjust it as you get closer and in accordance with a bit of common sense - one of our major airlines has been wondering why they have had so many lighting strikes over the years - I suspect that this may have something to do with it.
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a massive CB can be visually identified ahead, and either nothing shows up on the radar at all, or just a patch of green - it is not until you are within 50 or so miles of the CB that it then changes to yellow and then changes to red
Bendix said the fix was to remove the radome and bake it in a special oven until all moisture in the radome was evaporated. Then examine the radome for damage to the skin and repair it. It worked fine after that. Usually if radar is playing up it is a servicing problem - not a radar design problem.
BalusKaptan
I agree with you. I too would not fly over a red return. Those that I was referring to are yellow or green, which with modern, multiscan, fully automatic gear, are generally pretty innocuous.
By that I am not advocating flying through all yellow, but if it is a choice of a 50 mile diversion or the possibility of a short period of nil to light turbulence, I will not hesitate to take the yellow. Green is not even worth discussing. Multiscan systems show far more than previous units, and oftentimes the systems are overly sensitive. To hike up the gain only makes them moreso. Where the gain is useful is to give advance warning by picking up lighter returns at distance, but is not terribly viable as an avoidance tool.
Old methods were valid on older systems, they are not valid on the newer gear. I reckon the manufacturer knows a helluva lot more about radar/interpretation, than I ever will, so I am comfortable using the system the way the designers intended.
Hence my request of Centaurus that he qualify his observations, they do not necessarily apply the newer gear that some of us have at our disposal. One dosen't fly an A330 the way we used to fly Austers, so why would we not adopt the same philosophy to the use of other type of modern equipment.
Maui
I agree with you. I too would not fly over a red return. Those that I was referring to are yellow or green, which with modern, multiscan, fully automatic gear, are generally pretty innocuous.
By that I am not advocating flying through all yellow, but if it is a choice of a 50 mile diversion or the possibility of a short period of nil to light turbulence, I will not hesitate to take the yellow. Green is not even worth discussing. Multiscan systems show far more than previous units, and oftentimes the systems are overly sensitive. To hike up the gain only makes them moreso. Where the gain is useful is to give advance warning by picking up lighter returns at distance, but is not terribly viable as an avoidance tool.
Old methods were valid on older systems, they are not valid on the newer gear. I reckon the manufacturer knows a helluva lot more about radar/interpretation, than I ever will, so I am comfortable using the system the way the designers intended.
Hence my request of Centaurus that he qualify his observations, they do not necessarily apply the newer gear that some of us have at our disposal. One dosen't fly an A330 the way we used to fly Austers, so why would we not adopt the same philosophy to the use of other type of modern equipment.
Maui
Last edited by maui; 7th Jul 2010 at 23:31.
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Maui,
Yes, I agree with that generally. I would look at the surrounding area when contemplating penetrating a yellow area, try and assess whether it is going to stay yellow, width, height etc or whether it may still be developing. Don't want to commit to penetrating it briefly just to have it turn red at the last minute. I'm sure we have all observed, during daylight, a yellow return that when looking out the window is still in the growth stage that over a period of 5 - 10 minutes adds several thousand feet and starts discharging and as I are deviating around it turns red on the radar.
Yes, I agree with that generally. I would look at the surrounding area when contemplating penetrating a yellow area, try and assess whether it is going to stay yellow, width, height etc or whether it may still be developing. Don't want to commit to penetrating it briefly just to have it turn red at the last minute. I'm sure we have all observed, during daylight, a yellow return that when looking out the window is still in the growth stage that over a period of 5 - 10 minutes adds several thousand feet and starts discharging and as I are deviating around it turns red on the radar.
I am afraid to say I have to agree with Mr 'Molsie' I don't have the same radar as a 'NG', don't have 'Cal', but have gain control in 'Auto' or 'Max'. 'Auto' is supposed to optimize antenna sensitivity but sometimes misses a 'dry' or decaying cell. We also have a 'Man' or 'Auto' tilt function. (744). While the base mode in cruise is 'Auto' with 0.7 degrees nose down (in 'auto' tilt) I always have a look around in manual tilt and 'Max' changing the range as well. At the risk of stating the obvious I also like to turn down the lights and look out the window to get a feel for the sky. Use all the functions and keep looking around. I'm not keen on plowing through the 'yellow' either, it puts waves in my cofee.
