Wind in m/s?

[Hippo]

Is really how it's done in eastern Europe? I would have thought giving winds in km/h would make life much easier for navigation calculations, etc?

[EagleEye]

Don`t know how it is in eastern europe but in europe general aviation informations are given in nautical miles for distance, (wind)velocity in knots (Knots...WTF?;)) and height in feet. A pilot (in reallife) should know the conversion factors...:)

Edited April 17, 2009 by EagleEye

[Zardiz]

atleast here (Finland) we do use m/s from military to weather reports :)

[sobek]

m/s is the si (système international) unit for velocities, although general aviation uses knots AFAIK.

[Fudd]

Its not that difficult: xm/s * 1km/1000m * 60sec/1min * 60min/1hr = xkm/hr

 

or just times it by 3.6 and you get your answer

[advent_m]

3.6, not 36.

[Mugenjin]

or times it by 1.94 or roughly 2 and you get the m/s in knots.

[SSneg]

When exactly do you have to calculate wind speed for navigation (unless we're talking single-seat attack hot-air balloon here)?

[EtherealN]

Well, to be quite honest SSneg, we do it at my club when flying cross-country even though we have satnav, and we do that including wind speed. (We have to, even a slight wind can throw you wildly off course if you do not allow for it.)

[Zorrin]

It's for when the GPS goes down and you have to rely on your chart, stopwatch and accurate headings. Then it really helps!

[EtherealN]

Yup.

 

It should be noted that GPS is not rated to be a primary navigation instrument in commercial aviation. One of the reasons for that in civilian life is that the GPS network is a military system, with two bands (civilian-accessible and military-only), but the US Air Force does reserve the right to shut down the civilian part without any notice if they deem it necessary for national security.

 

...and of course, if the system came out of syncronization (they have to actually adjust their atom clocks for relativistic effects continually) you would inside a day have the system giving errors in the multiple-kilometres range. So one day after the system beginning to drift you have errors bigger than a good metreport and a good navigator with a stopwatch would get.

[SSneg]

Well, to be quite honest SSneg, we do it at my club when flying cross-country even though we have satnav, and we do that including wind speed. (We have to, even a slight wind can throw you wildly off course if you do not allow for it.)

 

99% of the time you use satnav or just punch the numbers into a calculator so you don't care if it's knots or m/s or even yards/minute. 1% of the time you calculate everything yourself, which is an awful lot of things to calculate, so changing it from m/s to km/h should go unnoticeable. So, again, why care?

[EtherealN]

You care because you don't get a license if you can't do it, and you don't keep your license if you can't do it. (Though, here in sweden it is not technically illegal to fly without a license as long as you don't fly in controlled airspace.)

 

And tbh, it takes longer time to do it with a calculator compared to just having your pen and your transporter (no clue if that's the proper english word - we call it a "transportör"). You just check airspeed and the compass heading to the next waypoint and draw that, check the wind direction and speed from the metreport and draw that, and voila!

 

The one thing the calculator would be good for is if you have some arcane numbers and need to convert between, say, an m/s wind speed report and the knots on your IAS. After that you may as well fly on the satnav, but if you haven't prepared yourself with anything but the satnav you are commiting massive fail on safety precautions.

 

It is not a massive lot of things to calculate. It's a total of three lines drawn quickly on your map.

Edited April 18, 2009 by EtherealN

[Yskonyn]

Yup.

 

It should be noted that GPS is not rated to be a primary navigation instrument in commercial aviation.

 

I think you're not quite correct here, EtherealN.

 

GPS is now, in fact, a commonly used navigation instrument in commercial navigation.

Our 737 for example, first uses the GPS signal and only reverts to IRS navigation when it does not have the GPS anymore.

Also there are procedures like GPS approaches slowly entering service around the world on airports. Mind you these are different that RNAV (Area Navigation by means of 'fixes' (google that term ;) ) procedures.

 

EDIT: Now I have thought about it, I am doubting my statement above. It might very well be that the main navigation system is still the IRS and it only gets a position update from the GPS to correct for drift the system has over time, especially in areas with low VOR (that's a navigation beacon which sends out beams all around (360 degrees) so you can ride one of those beams (called radials) to navigate to a point, the beacon itself or another beacon for example) coverage.

I'll look it up in my manuals and report back.

Edited April 18, 2009 by Yskonyn