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PPL student, wondering on how this practice is viewed. The aircraft I'm learning to fly in has a small Dynon EFIS which displays horizon, airspeed, heading & altitude. It also has a regular altimeter.

Assuming I'm going for a local flight, returning to land where I departed, is it OK practice to leave the Dynon on QFE and the Altimeter on QNH? This way I don't have to change any settings.

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  • $\begingroup$ I curious why you think that using dual altimeters for what they are intended for might be a problem? $\endgroup$ – Jamiec Mar 28 '17 at 11:21
  • $\begingroup$ Are you in a place that uses QFE for terminal operations on a regular basis? (Standard practice is to use QNH throughout, except in a few oddball parts of the world where QFE is used in the terminal area...) $\endgroup$ – UnrecognizedFallingObject Mar 28 '17 at 11:43
  • $\begingroup$ I'm wondering as I'm coming up for my skills test soon. It's maybe not so clear cut as one altimeter is embodied within the EFIS. The airfield I fly from is at around 400ft AMSL, so QFE is used. $\endgroup$ – andy-m Mar 28 '17 at 12:47
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I would turn it the other way around. Assuming the Dynon EFIS is your main flight instrument I would dial in QNH or QNE (depending on your altitude). Common practise is to always have the second altimeter set to QNE (1013.25hPa; 29.92inHg) but if you do not need an altitude reading in Flight Levels it's fine if you set up one altimeter to QFE.

But remember: Even using this practise you HAVE to change the settings. QFE and QNH are both depending on the local pressure and therefore change pretty often. If you are on a cross country flight you then have to change both altimeters to different settings in order to have a correct altitude and a correct height readout.

Also make sure that you always use the same altimeter for altitude and the other one for height so you won't use faulty values from the wrong altimeter!

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  • $\begingroup$ I'd emphasise that last point. No quicker way to fail your test than using the wrong one. $\endgroup$ – Ben Mar 28 '17 at 20:20

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