How to use a WX-Radar

[Norwegian]

Hi, is there anyone that can give any clues about how to use a WX-radar when flying. I am looking for the proos rules of thumb.
In the instruction manual for my WX-radar system its only system descibtion without any good "how to use it " guide.

Our wx-radar system is a collins WXR-350.

thanks

[Genghis the Engineer]

Not really a flight test subject, moved from FT to Tech Log.

Genghis
Flight Test Forum Moderator.

[typhoonpilot]

Two words, Archie Trammell. Find some notes from one of his courses and you will learn all about how to use a weather radar.

Typhoonpilot

[con-pilot]

To properly answer your question would take way too much space here. However the most important thing you need to learn is the use of the tilt knob. Modern day radar is pretty fool proof and about the only way one can get into trouble is misusing the tilt.

A basic rule of thumb is while at altitude enroute adjust the tilt to show very light ground clutter toward the outer of the screen while in the 80 to 120 mile (depending what range scales your radar has), by doing this it is easier to detect weather and not confuse thunderstorms with ground clutter.

One other thing to remember is that when descending, below the mid-twenties, start tilting the radar up, what could be above you is more important than painting the ground.

[dicksynormous]

I believe BMI may be able to help

[square leg]

Very briefly:

Before line-up, switch it on (provided no buildings / A/C are in front of you.

Line up on the runway and once lined up, tilt it up to max (15°), then slowly scan down till you have ground returns. Then tilt back to 5° up for departure. You typically achieve this kind of climb angle (depending on your A/C's performance)

As you get higher, you'll start scanning in such a manner to have ground returns on the edge of the screen.

Typically you'll have a setting of -1.25° (down) at cruise level (FL370). This also depends on range of your ND. Some people use 0° tilt in cruise.

Keep the GAIN in AUTO (general rule).

When descending, you'll slowly start tilting to the up position and during approach you will be back to your 5° up as you want to scan the missed approach path. Typically one chap will have the EGPWS on the other ND.

Use it as much as possible to get practice.

If VMC and avoiding CB's, you'll get an idea of what you'll be avoiding when avoiding embedded TS's.

As sed, very briefly.

[Norwegian]

What is BMI,

Thanks for the tip of A.trammel

I have tried it and it really works.

Basicly you altitude ex. fl 290 correspond to 29 miles on your radar screen. You should tilt radar that ground clutter becomes noticable around 29 miles, then tilt the radar 10 degrees up, which should align the radar beam with the flight path. this works on decend also.

Thanks

http://www.avweb.com/news/airman/184282-1.html

link to radar managment:ok:

[SuperRanger]

norwegian,

for X-band WXR which has a slightly narrower beamwidth (for same antenna size) i use, -1° for target at 160nm, -2° for 80nm, -4° for 40nm and -8° for 20nm. i also noticed that on modern WXR, possibility due to the sensitivity timing control, if a range of 40nm or less is selected, the sensitivity level drops.

if you really want to pickup the most thin cloud layer you might need to leave your range at 80nm with occassional selection of 40nm range.

with most modern WXR also there doesnt seem to be any variable gain selection in WX mode. i find increasing the gain helps tremendously in pickuing out the 'best' track. so at times, i have it in MAP mode at max gain!

hope these helps.

SR

[Hudson]

When cruising at high altitude in cloud or at night (30,000 ft upwards) set the Gain control from the Auto position to Max gain position. This gives extra beam power and allows better pick-up of tops of storms which normally do not have much moisture in the anvils or tops. Works a treat in the tropics which have huge tops.

The Collins WXR-700X Pilots Guide is full of good information and if you play your cards right any Rockwell-Collins agency will give you the book free.

Also read a fine book called Airborne Weather Radar - A User's Guide, by James C. Carr. Order it from USA phone 1-800-862-6657. It is around $40 USD and nwell worth it.

[jafo33]

Can anyone tell me if these techniques for basic tilt alignment would work with wx radar fitted to a turboprop operating at FL100?

Also can anyone tell me what the red 'T' means that appears in the screen when the gain is turned up to max?

[Prof2MDA]

I would not recommend Archie Trammel. Far better is
Dave Gwinn. Not even a comparison, IMO.

[Hudson]

Square Leg. With modern radars there is no problem with using the radar when on the ground lined up regardless of an aircraft in front of you. Page 93 of the Pilots' Guide for Collins WXR 700X Weather Radar System states: "There is no apparent reason for restricting ground use - however it would be prudent to turn off the weather radar at the gate (Off, Standby or Test) and enable the weather radar after leaving the gate.