DAMN IT. I JUST DONT GET QFE 2 QNH SETTINGS in F-5E

DAMN IT. I JUST DONT GET QFE 2 QNH SETTINGS in F-5E

I want to punch a hole in my panel.

On approach I am given QFE of 25.23.

Bloody hell what do I do with this number. The F-5E altimeter goes to 2810. !!!!!!(*)()(*)(*))_(*(

"Yup, take the ad elevation in feet div by 30 (or 27 if you prefer) and that gives you a number to add to the QFE in hPa to give a pretty good approximation of the QNH. Look out for different units of measurements - obvious but important!"

On this mission at arrival field, elevation 1360 meters/4460 feet. That means that if set on ground the altimeter setting is 2968.

So how in the bloody hell do I take ATC QFE of 25.23 and turn it into correct QNH altimeter setting of 2968 or 29.68 . I am not seeing any relationship where 27 or 30 goes into.

What does that mean, as applied to DCS: F-5E?

It is embarrasing as it is annoying. I am missing some basic understanding of the proccess, but do not know what it is.

Use QNH, IIRC in EE.UU they use QNH not QFE. DCS World ATC only tell QFE, but you can see the QNH in Briefing below WEATHER.

Thank you all. But but my question is not answered. I am recovering on a field that is not departure, and ATC gives me QFE. In mission briefing it is also QFE, no QNH. So when given arbitrary QFE, what is QNH?

OK look on standard day where QNH is 760/29.92 20 deg. C = 68 F , QFE is 28.18

29.92 / 28.18 =1.0617

Now lets go my situation, I am on an approach and I am given , by ATC, QFE of 25.23.

If I multiply QFE 25.23 * 1.0617 = 26.76.

Minumum QNH? altmeter setting on DCS:F-5E is 2810. So WhatDuhhFFF!!!WTF!

That means I am missing something, or there is something effed in the sim or in the module. I am clueless, and frustrated.

Two Options:

- Adjust pressure so field elevation is correct on altimeter

- Adjust pressure so altimeter reads 0 on the airfield*

(*Wx conditions may not allow this)

Ahh!!!! I am in the air thousands of feet above the field, going 500 knots, with low visibility.

I am given QFE by ATC of 25.23 for recovery(landing)

Now WHAT DO I SET MY ALTIMETER SETTING TO?????

Give this a shot.

Find your field elevation using F10 maps, TERPS, whatever. Divide field elevation in feet MSL by 1000. Round to 2 decimals and add this number to the QFE you are given. Put it in the window.

Unless I am wrong this should get you close enough for shooting a TACAN approach to mins in the F5.

EDIT

I never even read the first message of the thread but this works to with 10 feet in your above example.

Field Elevation (4460) / 1000 = 4.46

QFE (25.23) + 4.46 = 29.69 (Within .01 in/mg AKA 10 feet of field elevation)

Obviously there will be some variations here with large deviations away from ISA but nothing any of us mere mortals would be able to detect shooting said TACAN down to mins

Here's the quick, easy way - Prior to takeoff at your home airfield, look on the chart and get the field elevation. Now turn the altimeter setting as required until you see that altitude shown on the altimeter. Now go fly and don't worry about it for the rest of the flight. What you've done is set the altimeter to show you your altitude above sea level. If you're not using dynamic weather, then the altimeter setting will be the same everywhere in the virtual world below transition altitude.

In meters or feet? Where is this actually written? I have seen no accurate description of this process.

OK, but once again. Are we in meter or feet? 4446 that is feet or meters? Elevations on map in DCS are in meters. So we have to first convert field elevation to feet. Then divide by 1000 . Then add that to QFE. That is has been most hair ripping frustration on this site, and others . They are thowing numbers without units then jumble QFE and QNH into ununderstandable jiberish.

Are you referring to my method Dave with your questions about units?

I cant tell. Everybody is throwing numbers without units, and its killing me. Aviation training must be chaotic. I am prior service U.S. Army. All of out units, including working with JTAC, were metric. 1000 meant meters.

Okay right on. Poor assumption on my part, I was stating all altitudes in feet, pressures in inches of mercury as are used in the F5.

My DCS map displays altitudes in feet. I don't know if it is possible to actually make it show meters, but maybe it is. Regardless, I doubt an F5 could ever use any runway at 4446 meters MSL. That is 14,500 feet, you would have to measure the F5's runway at that elevation in miles not feet. What airport are we talking about here? that might be a good start.

In Options/Gameplay/Units set to - METRIC.

If you set it to Imperial it gives numbers in feet but unit measure in meters. Confusing.

So it would display elevation at 561 meters (1860 feet) as 1860 meters. Which when interpreted with zero visibility, equals crash and in RW would be a primary cause of mishap.

So I leave it at Metric. Then on Map I get field elevations in meters which I convert to feet.

That number would be divided by 1000 and to that would be added ATC QFE to get the correct QNH Altimeter setting for that airfield at time of arrival. This bit took me way to many few frustrating hours to untangle. JHC!

Reptor9. I am trying not to overthink it. I am trying to think it correctly. I have no problem with concept of adjusting altimeter at departure field, prior to departure. That makes perfect sense.

It on the arrival end, on a different field that I was/perhaps still had issue understanding.

Fly 150 miles, about 30 nm away from destination, call Inbound and receive active runway and QFE . I was , only slightly ever confused as to what I was supposed to do with , and how an arbitrary QFE from ATC (25.53 for exp.) translated into setting QNH Altimeter setting, as I am flying at 15500 ft. (calibrated) but calibrated to altimeter settings of my departure field 150 nm away. I am still confused, as to how it is suppoused to save me from CFIT- ing in front of my non-existent friends.

OK, but when I log time on Prepare3D sims I get similar ATC traffic.

Assuming you set QNH at takeoff or sometime in flight and you receive QFE info at the destination airport you have a few options:

1. Continue using your previous QNH value. If the temperature is not extreme or the weather not dramatically different then this QNH will be close if not identical to the new place.

2. Convert to QFE operations for landing. It's a perfectly valid form of altitude management provided you consider all the effects. But certainly wait until in the terminal area before the change.

3. Back-calculate a QNH from a QFE. This is probably a bad idea compared to 1 & 2.

Maybe everyone already has a perfect understanding of what QFE and QNH are, and what they mean, but just to be on the safe side, I really can't recommend this video enough:

Altimetry basic principles by the ICAO

Armed with this knowledge, calculating QNH from QFE (or the other way around) is really just a bit of math, and many examples have been provided already.

The different units of measurement don't make this any easier, but it just remains math to calculate hPA from InHG or to calculate feet from meters, and vice versa. Of course things would be a bit easier if the entire world was ready to agree on a common measuring standard. It is called altimeter after all, nudge nudge. ;)

Of course I hope that the DCS ATC will receive a big overhaul so that pilots can request both QFE and QNH, whichever they prefer. Especially in a dynamic weather environment, this would be invaluable.

Finally, one point to reiterate: Depending on the current atmospheric pressure and and airport elevation, it may be impossible to set barometric altimeters to QFE, in which case QNH would be the preferred reference.

This is an interesting discussion. I tend to use QNH during flight, but always adjust to the QFE for the airport I’m just about to land at. I find it easier to land when the altitude is stated as above where I am about to land, and not having to do mental calcs to work out how far above the runway I am.

What about when your starting in a helicopter on the ground in a small valley between the hills. The worst part of it is, that the sim is setting the altimeter to zero. Something I would never want at anytime in the real world unless doing aerobatics low to the ground.

I don't reference maps to know I need to stay at or above 8000 so as not to run into anything for nothing you know. And in DCS I find out I have no idea what my starting elevation is and some joker has set my altimeter to zero.

So I'm trying to read the F10 view and read elevation lines trying to figure out if its in feet or meters and where about's am I in altitude to the nearest elevation line on the map?

I want to know if there is a setting to set all aircraft/Helo's to the altitude its at on the ground when you start the sim.

I find it easier to land when the altitude is stated as above where I am about to land, and not having to do mental calcs to work out how far above the runway I am.

That should work very well for VFR approaches.

As soon as you venture into IFR, it's all altitudes MSL, and thus pretty much requires QNH. :smartass:

What about when your starting in a helicopter on the ground in a small valley between the hills. The worst part of it is, that the sim is setting the altimeter to zero.

Yeah, it would be nice to have the option to preset either QFE or QNH or the standard pressure setting at mission start, and even cooler to have a global default and the option to override that for each type of aircraft. If would also be nice to be able to retrieve the aircraft's altitude at mission start from the briefing.

I think the F2 view should provide the actual altitude MSL, though, and objects like FARPs should also give a pretty solid elevation on the F10 map as long as they're visible on it. Of course these are just workarounds, but as long as these map options are available, I think it's fair game to use them in order to overcome problems like altimeters that are preset to QFE when the starting altitude is not provided.