Aircraft Radar: Your Techniques

[757BBJ_Capt]

I was asked last week by one of our F/O's how to use our radar in the manual mode. I could tell that what I was saying to him was too detailed and involved for his experience level and there is sooooooo much to a radar, I just confused him. That gave me the idea to put together a muanual for radar use (nothing aircraft specific, just a radar's use in general), so I thought I would get on here and ask you guys how you operate yours and what, if any, special techniques you use to get the picture you want. Just plain english I could put in a manual and pass along when asked to give a basic knowledge and understand of how the radar should be operated. Rules of thumbs, ground use before departures, climbs settings, decent settings, ect. That sort of thing. I have Archie Trammells little book, but some of those things he says can get you into lots of trouble about FL310. Any input would be appreciated. Thanks in advance......

 

[semperfido]

tilt 101--in manual mode set range 50 nm and if you can paint the ground with bottom of beam @ range 25 you will paint any wx in front of you...archie circa 1981 otherwise ours spends a lot of time in auto

 

[Groucho]

I have been fortunate to attend several of Archie Trammels radar seminars in my career and alot of information is covered. The most important information that I can rememnber is:

1. The GRAVE index. GRAVE stands for Geography, Reflectrivity, A=AC or convective advisorry note, cell velocity and echo intensity. Archie admits that most of these factors do no relate to on-board radar. They are the preflight items he notes to determine how he is going to interperate what he sees. The higher the GRAVE index the more cautious you should be about cell avoiadance.

Geography means that a cell in eastern CO or NE or KS is different from an afternoon airmass cell in FL. Reflectivity is given in special Wx reports from the WX 57 radar and has a number associated with it. I am sorry that I can't remember the numbers associated with this part of the accronym but it relates to the reflectivity of ground based returns. AC note, the convective outlook looks at the chance of severe TRW. A strong possibility of severe TRW means that you might want to use the maximum distance avoidance techniques. Cell velocity is related to intensity and steady state or leaning storms, these are the types that create the most hazard. Echo intensity is the number associated with the level of the storm, ie. level 3 echo, level 4 etc.

2. Never fly into a radar shadow, No exceptions. A radar shadow occurs when a blank spot appears behind a cell on the radar display. It means that the echo is so intense that it is relecting virtually all the energy and there is none able to penetrate beyond the cell. It's like looking a brick wall. You don't want to fly through a brick wall. In order to see shadows the return should always have a small amount of ground paint in it. Generally the outer third of the display should have a small amount of ground return to let you know where the radar beam center is. If you are painting the outer third the beam center is near your flight axis. There is a formula for beam center but I can't remember it.

3. Tilt control is the most importatnt function and should be adjusted contstantly to look at the entire echo, expecially during climb and descent praticularly in jet aircraft. The radar gain is changed by a circuit called stc, or senitivity time control. Distant targets will appear stronger than they are and near targets will be attenuated to make up for their closer proximity. This has to due with reflected radio energy and not wx phonema. It could be thought of as being similar to different lense types on a camera. They all distort the light signal in some small way. The 50mm lens is the closest to the human eye and the 50 mile scale on a radar is the least attenuated and the most accurate from a radio energy / wavelength standpoint. It is the closest to "what you see is what you get." If a cell is not red at 50 miles but gets some red as you near it this is due to stc and most likely not a wx change.

5. Avoid hook and pendant shaped echos.
In a jet at altitude try to deviate up wind if possible.
The mark one eyeball is praticularly effective combined with radar even at night.

 

[Huggyu2]

I've been flying jets for 20 years, so let me tell you how it is... By the way, what's a "radar"? I've never flown with one of those.

 

[Stifler's Mom]

Keep adjusting the tilt up until all of the scary stuff disappears.

 

[HMR]

You guys have "Auto" mode?

Luckyyyyyyyyy!

 

[Koslen]

Oh thats good stuff! Theres only one thing you need to know about radar. Don't rely on it. But if you are painting weather don't fly through the red parts. Have fun!

I've been flying jets for 20 years, so let me tell you how it is... By the way, what's a "radar"? I've never flown with one of those.

 

[Makesheepnervus]

I use all the techniques taught by Archie Trammell, the key to his methods is correct Tilt control. A quick summation of what I do is;

Tilt up 10' in the terminal area

Set bottom of the beam on the Horizon between 5,000 and 15,000 agl
(which is approx 2.5' up for most 18'' antennas)

In cruise Set Range at 50nm to 100nm and "park the tilt" down so as to paint ground at the top

When you paint cells tilt down occasionally to paint ground, if the area behind the cell still shows no return, it is a radar shadow and you don't want to go there!

There's loads more if you want to know more, buy the tapes.

 

[LJ45]

Stormscope

With a Stormscope "lighting bad" heavy rain "will not kill you" helps in the south!

 

[Flying Illini]

I'll help you but first I need you to walk in my resume at your company


Radars have an "auto" mode?!

 

[Flyforyou]

For those aircraft without EGPWS, this method works spot on for terrain avoidance. This came from Archie of course...

Tilt radar down until the distance out you paint the ground is the same as your altitude in AGL... example: you're 25,000' AGL, tilt to paint at the 25nm range.

Now tilt up 6 degrees.

You now have your radar set to paint down 400' for every 1nm forward, so at the 5nm scale, you're painting down 2000'(moutainous terrain clearance altitude). Don't let anything get inside of 5nm and you're golden.
Try this on a clear day to test it out. On final at 400' AGL, check to make sure your radar is painting ground at 1nm out.

The article goes on the explain how this method could have easily prevented that military 737 accident over in Dubrovnik a while back.


Fly

 

[Lead Sled]

I have Archie Trammells little book, but some of those things he says can get you into lots of trouble about FL310.

I think you're trying to reinvent the wheel. And I agree with you, Archie's stuff could get you in a bind at altitude; but it's better than no training at all when it comes to using the weather radar. Over the years, I've had the opportunity to attend 4 or 5 of Archie Trammel's seminars (The company sent us every couple of years as part of our recurrent training program.) as well as Dave Gwinn's (Honeywell's) course and a couple of others. Dave Gwinn's course is far and away the best. I would highly recommend that you guys who have never attended a formal weather radar course to make arrangements to attend one. At one time the Honeywell course was free - you just had to reserve a slot in the various cities around the country where it is given. Check out Gwinn's website at www.davegwinn.com

'Sled

 

[bafanguy]

A good book: "Airborne Weather Radar: A user's Guide" by James C. Barr, Iowa State University Press, circa 1993.


It has comprehensive coverage of all the theory and operating techniques one would need. Written by a working airline guy.

The seminars are nice because you have someone to answer your questions, but you still need a good reference manual. Manufacturer's manuals are OK, but not as "textbooks" on the subject in general.

 

[aeronautic1]

If....

... you ever flew air ambulance for Roy at B&C, then the onboard radar was the one peice of equipment that you were absolutely - positively - always - never relied on to work.

Instead, you take your right hand, palm facing down, place on your forehead as if you were shielding your eyes from the sun and then slowly move your head from left to right and repeat.

Indian Radar.