stringybfc

Support for QFE/QNH, hPa/inHg

Recommended Posts

Hi Dave,

If flying patterns, it would be great to get the altimeter as QFE rather than QNH.  As P2A knows the height of the airfield you're at, could a QFE reporting option (maybe a config checkbox) be added?  Whilst I don't believe the sims report QFE, this could be derived: QNH + (aerodrome AMSL / 30).

Additionally, the ability to report QNH/QFE in either hPa or inHg (maybe again with a checkbox option) would be great.  Again if it's not presented directly by the sim, if memory serves me, it's 1 inHg = 33.8639 hPa.

Thanks
Karl

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Karl,

I'm not aware of QFE being reported by ATC either.  Are you saying that is common practice in the UK or other countries? 

Seems like it is something a pilot would calculate or just set the altimeter to read 0 feet prior to takeoff.

Dave

  • Upvote 1

Share this post


Link to post
Share on other sites

When I was learning to fly gliders (not this coming year due to funds!) we set the altimeter to read 0 feet prior to takeoff as we were not going on any cross country jaunts, nor landing out from the airfield (hopefully!).

You could do that when flying patterns, or perhaps take a note of the altimeter reading - if you know you're say, 600 feet AMSL on the runway, just subtract that from your heights in the pattern. Or watch the rad alt, depending upon the instrument suite of the plane you're flying. :happy:

Share this post


Link to post
Share on other sites

Sorry, that might have been a little misleading - the ATC wouldn't verbally report QFE, but it's not uncommon for QFE to be reported on a local digital ATIS service, eg: http://cityairportandheliport.com/info/, so for that component I was wondering if it might be incorporated in the "info" tab for an airfield. As you'll see in the top left box, both QNH & QFE are reported.  This ATIS display is shown on monitors in the flying school & tower, and used by pilots when making initial contact with the tower.  It is something that's easy to calculate, so not essential, more of a "nice to have".

As for the altimeter setting - in UK we receive this verbally in hPa rather than inHg, so this is something that would be really advantageous to have a preference setting for, plus, some payware aircraft only provide a hPa subscale.

Thanks
Karl

Share this post


Link to post
Share on other sites

To get altimeter settings in hPa rather than inHg, set the Units Type on the ATC Settings tab of config to Metric_Ft. 

You can also check the option on the P2A Settings page for "Use Decimal instead of Point" to get frequencies with the decimal term instead of point.

Thanks,

Dave

Share this post


Link to post
Share on other sites
17 hours ago, stringybfc said:

Hi Dave,

If flying patterns, it would be great to get the altimeter as QFE rather than QNH.  As P2A knows the height of the airfield you're at, could a QFE reporting option (maybe a config checkbox) be added?  Whilst I don't believe the sims report QFE, this could be derived: QNH + (aerodrome AMSL / 30).

Additionally, the ability to report QNH/QFE in either hPa or inHg (maybe again with a checkbox option) would be great.  Again if it's not presented directly by the sim, if memory serves me, it's 1 inHg = 33.8639 hPa.

Thanks
Karl

You have to calculate QFE manually or create a gauge that can do it so that you can set the altimeter correctly. Generally speaking people use a rough estimate of 30 feet per Mb but that's not accurate enough. You have to calculate "exactly" as the sim does in order for accuracy. The sim calculates millibars to be 29.54545 not 30. I had to do this for the Super VC10 upgrade, So it's pukka.

So if your airfield has an elevation of 1,000ft and the QNH is 1013.2 then your QFE is 979Mb.

As has been said above you could if just doing touch and go's set your altimeter to zero before take-off. But if arriving from another field you would need to set the altimeter. For places like Biggin Hill it is essential as it has an elevation of 600ft. And over the years there have been some sad accidents caused by pilots not setting their altimeters correctly.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now