Guys, a weather radar is impossible in flight sim. End of story. There is absolutely no moisture in the sim at all. The rain, the ice, and the slick runway are all just visual effects. Note your braking on a wet runway is exactly the same as a dry runway.

 

Weather radar needs moisture to bounce off of. If there is no moisture, there is no radar return. The sim doesn't show rain outside of the immediate vicinity, so you'd pick up nothing unless you were already in it, which is pointless. If you don't believe me, load up at an airport that has precip, and then switch to the tower view of an airport that has rain on its METAR a few miles away, and you'll note it's not raining there.

 

I might have completely the wrong end of the stick here but, to my understanding, third party weather (e.g. Acive Sky) injects the weather itself hence avoids the problems of FSX weather radar (Active Sky even has its own WXR). So would it be possible for PMDG to do a WXR (fully integrated into the ND etc) for third party weather users? Yes, users of default weather wouldn't be able to use it (at least not with 100% accuracy) but I'm guessing most people here use third party weather anyway.

As I said, perhaps I have completely misunderstood the problems with WXR and this is complete giberish. Hopefully not.

 

Will, that's partially right. It doesn't escape the confines and restrictions of the FSX weather system, however. All it's doing is injecting METARs into the system, and in some cases, interpolating values between those weather stations. The weather "radar" included in those add-ons is not a radar at all. It's a precipitation likelihood display, which is not weather radar in the slightest.

 

Weather radar says "moisture, to this intensity, can absolutely be found here."

The "radars" in any add-on say "you might find precip here."

 

You can certainly integrate this useless tool into the NGX through messing with the panel.cfg, but you're going to be doing it at the cost of useful information (likely covering over one of the EICAS displays that provides useful information, as you'll see in some peoples' posts here in the forum).

 

Kyle,

i understand that it has been talked for a long time, but that's the first time that i noticed the need of the Radar, thanks cheers everyone!

 

I understand what you were going for, but there are certain topics that are best avoided. All they do is devolve into endless banter and whining. Weather radar is one of them.

 

Those who fight "against" the feature aren't fighting against your reasoning. Most of us fully understand the need for weather radar. Believe you me, I would've definitely liked having one in this situation a few weeks back:

 

 

(before anyone runs off thinking I'm an idiot, the full story is here that describes the planning behind the action we took)

Anyway, I just don't understand the reason for their decision, but would like to know more about the technical end of this. I understand radar use and theory pretty well my military days, but just have to confess ignorance in this arena.

In which case you will already know that WXR works by bouncing radar waves of water droplets. FSX does not model water droplets, therefore, there is nothing to bounce the radar waves off! "But what", I hear you ask, " about the others WXRs you can buy?". I am glad you asked me that... They tell you where FSX has put clouds. Yes, the same clouds you can see out your window.

 

I might have completely the wrong end of the stick here but, to my understanding, third party weather (e.g. Acive Sky) injects the weather itself hence avoids the problems of FSX weather radar (Active Sky even has its own WXR). So would it be possible for PMDG to do a WXR (fully integrated into the ND etc) for third party weather users? Yes, users of default weather wouldn't be able to use it (at least not with 100% accuracy) but I'm guessing most people here use third party weather anyway.

As I said, perhaps I have completely misunderstood the problems with WXR and this is complete giberish. Hopefully not.

You are sort of half right. Because Active Sky and others injects the weather into FSX, it knows what weather is where, so it can provide an accurate and realistic weather radar. However, PMDG, and every other sim using FSX can only know what FSX can tell them. And since FSX can not tell them about weather, they can not tell you.

I have a slightly off-topic question. Are Wx radars hazardous to the health of ground crew or those near it?

Are Wx radars hazardous to the health of ground crew or those near it?

 

Yes and no. Yes, if they're on. No, if they're off. WXR uses microwave radiation to detect moisture. Yes, microwave radiation. I'm sure you know of other applications of such radiation...

 

You'll note there's a checklist item for all weather radar-equipped aircraft to turn it off after landing. The rampies sure appreciate it, especially given their location for the pushback...

 

Side note:

Radar guns use the same principle. Ever see a cop running radar in the rain? Nope...

There have been studies to show it's not necessarily healthy to be blasted by radar guns all day. This is especially important for those officers who have cars equipped with those trunk-mounted radar units that aim toward the driver (though on a slight offset, to see by the car body).

... Note your braking on a wet runway is exactly the same as a dry runway.

...

Not in an advanced sim, for example like the excellent LSH Maddog

Not in an advanced sim, for example like the excellent LSH Maddog

really?

Not in an advanced sim, for example like the excellent LSH Maddog

 

...which doesn't use FSX's weather modeling. It uses external methods as approximations, not actuality.

...which doesn't use FSX's weather modeling. It uses external methods as approximations, not actuality.

so why PMDG don't do the same?

so why PMDG don't do the same?

 

Because there isn't an accurate way to do it. How can I find out how much rain is on the runway? I can't. There are no indicators in the METAR. Can I look at historical data? Sure, but what rates go into SH, RA-, RA, or RA+? I can approximate those, but for how long during that hour cycle was it RA versus SH? Some METARs show RAB or RAE (for began and ended), but not the changes in intensity. Where is the sim variable for grooved runways? That affects water shedding and therefore braking. It's not there.

 

So, the last 5 METARs show RA, I can guess the new rainfall amounts are maybe 1/8" per hour and it dissipates such that there's 1/32" of water on the runway at any given time. With that, I can probably come up with some metric to calculate it all out, but it's not like Boeing is going to hand me some hydrodynamic equation for that. I'd have to infer it from some relatively rudimentary tables and interpolate.

 

Beyond that, how am I polling the data to get that history?

Am I querying real world weather from sites like NOAA, etc?

What happens if you're forcing different weather in the sim?

How do I avoid a processor hit for all of that calculation? Unless I filter it, it's going to be running histories for all of the airports in the world, and calculations on that aggregate data.

How far of a history should I take? Should I go back only three hours? What happens if the storm has been going for the whole day like this past "superstorm?" IAD was technically open, even though you weren't going to catch an operator trying to get a flight out in that. Simmers often intentionally fly into bad weather, so the "well the weather cancelled all of the flights anyway" argument doesn't stand up.

If I'm asking the algorithm to go back until it stops seeing RA-, RA, or RA+, that further increases the workload (and difficulty of the algorithms).

Do I narrow it down to the departure and arrival fields only? Sure, I can map that to run off of entries on the RTE page, but what exactly are we creating here? There's a fuzzy border between the plane and its interaction with the weather as it stands currently, but getting into weather history models, you're moving past that blurry line into a weather program.

 

They could do it, and some would consider an approximation better than nothing, but without the appropriate weather variables, it's very hard to implement accurately, at least up to what they'd consider to be accurate enough.

thanks very much for that Kyle, lots of Info from you every time(; cheers.

thanks very much for that Kyle, lots of Info from you every time(; cheers.

 

You're welcome.

 

For the record, even the FAA and industry (the airlines/business aviation/etc) have noted that there's room for improvement on how weather data is disseminated. It's something that will evolve (particularly in the case of RVR information, runway contamination, and a couple other factors).

 

Here's one of the tools that just got released not too long ago for evaluation and testing in the upcoming 2012-2013 winter weather season:

http://testbed.aviationweather.gov/winterdashboard

 

Basically, it runs probability models of winter weather in the future and gives somewhat of a stoplight metric as to how bad things will be affected. It's even weighted for the area. As an example, snow in MSP isn't as much of a big deal as it would be in ATL or CLT, because they're not used to it, or as equipped to handle it. If you click on the triangles next to the airport ID, you'll see potential alternates to that airport and probabilities there, too.

 

Kind of a tangent to the topic, but I figured it's somewhat to the point that even the real aviation sources don't have the best view of the weather when it comes to weather data.

Just ignore the thread if it bothers you that much, that's why I don't read a good chunk of them and that keeps the blood pressure down lol.

 

Some people have to respond to everything.

Either way, Radar or no Radar,

If all else fails, last resort eyeballs,

Grabbing stomach from your feet or head to put it back where it belongs, trim controls all over the show, ASI needle all over the place, Altitude all over the place, wrestling with slipping sideways like a dog on Ice,

It's time to Autopilot off, slow down, and take action.

Time to study the weather flying manuals lol

Yes and no. Yes, if they're on. No, if they're off. WXR uses microwave radiation to detect moisture. Yes, microwave radiation. I'm sure you know of other applications of such radiation...

 

You'll note there's a checklist item for all weather radar-equipped aircraft to turn it off after landing. The rampies sure appreciate it, especially given their location for the pushback...

 

Side note:

Radar guns use the same principle. Ever see a cop running radar in the rain? Nope...

There have been studies to show it's not necessarily healthy to be blasted by radar guns all day. This is especially important for those officers who have cars equipped with those trunk-mounted radar units that aim toward the driver (though on a slight offset, to see by the car body).

 

Interesting. A few posters replied saying the Wx Radar used Radio waves, not Micro waves. Either way, neither radio waves nor micro waves are ionizing forms of radiation, so neither have any chance at causing health affects [like cancer] other than burns when used at extremely high energy levels [i.E, your Microwaves]. I'm always interested in this stuff though, because I've heard a lot of pilots talk about the dangers of the radar to ground crew.

From a WXR manual.....

 

3. RELATED READING MATERIAL.

a. Barnes and Taylor, Radiation Hazards and Protection (London: George Nevnes Limited, 1963).

211.

b. U.S. Department of Health, Education and Welfare, Public Health Service, Consumer Protection and Environmental Health Service, “Environmental health microwave, ultraviolet radiation and radiation from lasers and television receivers – An Annotated Bibliography,” FS 2.300: RH-35, Washington, U.S. Government Printing Office, pp. 56-57.

c. Mumford, W.W., “Some technical aspects of microwave radiation hazards,” Proceedings of the IRE, Washington, U.S. Government Printing Office, February 1961, pp. 427-447.

4. BACKGROUND. Dangers from ground operation of airborne weather radar include the possibility of human body damage and ignition of combustible materials by radiated energy. Low tolerance parts of the body include the eyes and testes.

5. PRECAUTIONS. Management and supervisory personnel should establish procedures for advising personnel of dangers from operating airborne weather radars on the ground. Precautionary signs should be displayed in affected areas to alert personnel of ground testing.

a. GENERAL.

(1) Airborne weather radar should be operated on the ground only by qualified personnel.

(2) Installed airborne radar should not be operated while the aircraft is in a hangar or other enclosure unless the radar transmitter is not operating, or the energy is directed toward an absorption shield which dissipates the radio frequency energy. Otherwise, radiation within the enclosure can be reflected throughout the area.

b. Body Damage. To prevent possible human body damage, the following precautions should be taken:

(1) Personnel should never stand nearby and in front of a radar antenna which is transmitting. When the antenna is not scanning, the danger increases.

(2) A recommended safe distance from operating airborne weather radars should be established. A safe distance can be determined by using the equations in Appendix 1 or the graphs of figures 1 and 2. This criterion is now accepted by many industrial organizations and is based on limiting exposure of humans to an average power density not greater than 10 milliwatts per square centimeter.

(3) Personnel should be advised to avoid the end of an open waveguide unless the radar is turned off.

(4) Personnel should be advised to avoid looking into a waveguide, or into the open end of a coaxial connector or line connector to a radar transmitter output, as severe eye damage may result.

(5) Personnel should be advised that when high power radar transmitters are operated out of their protective cases, X-rays may be emitted. Stray X-rays may emanate from the glass envelope type pulser, oscillator, clipper, or rectifier tubes, as well as magnetrons.

c. Combustible Materials. To prevent possible fuel ignition, an installed airborne weather radar should not be operated while an aircraft is being refueled or defueled.

 

Standing in front of any Radar, playing with wave guides, or any microwave source is a bad idea lol