I’m finding that I read the instrument manuals a lot more when configuring my simulator to match them. Many aircraft are upgrading to Garmin G5 or the newer GI 275 instruments which are packed with functionality, and getting rid of older vacuum driven kit (and the associated vacuum pump), including some of those I instruct in.
I was surprised to see that the GI 275 does not support QFE, commonly taught in the UK to be used for landings, while the G5 manual makes no mention of it.
Does anyone know the reason why QFE isn’t recommended for this particular gadget? I wondered if it was because it had a reversionary mode (GSL) which switches to GPS derived altitude automatically should the static pitot input fail, and this would present an altitude similar to QNH.
Also, should instructors revert to teaching the use of QNH instead, as is done in almost every other country?
From page 37 of the pilot’s guide
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Interesting find, maybe it relies on QNH to proxy validate some computer air data? or generate some AHRS data?
I would expect such restriction to apply in G5 with OAT GAD13 interface, this calculates TAS & Wind from altimeter setting altitude, standard pressure altitude, temperature…puzzling why this applies to GI275 and not to G5 with TAS feature?
Worth checking sensitivity of GI275 air data and other extra functionalities to QNH…what happens to Synthetic-Vision when you move QNH from 950 to 1050 while flying? or on the ground?
QFE is a ridiculous hangover from the 1930s. That said, how can the system possibly know whether the number you have twiddled into it is QFE or QNH?
The difference between the highest airport in the UK and sea level is well within normal altimeter setting range. We’re not talking Leadville or Kathmandu here (where QFE might be useful, but would also be physically impossible).
QFE is indeed outdated and it can’t be used on the Boeing 738 as it’s use would result in errors with the GPWS and I suspect that the GI275 has similar issues.
The stronghold of QFE is the RAF who use it because it keeps cockpit workload down when recovering a fast jet in IMC using PAR.
As an instructor I don’t teach the use of QFE apart from when the military force me to use it and I would like to see is consigned to the history books.
I’m not a friend of using QFE any time. You haven’t proper separation from terrain (MSA’s are due to QNH), you can’t separate from foreign aircrafts etc, etc…
I can’t see lack of QFE at garmin as an issue.
I know that sometimes gliders are using QFE to know how high they are over airport w/o recalculating however if they go to cross country, QFE at the box is useless.
The stronghold of QFE is the RAF who use it because it keeps cockpit workload down when recovering a fast jet in IMC using PAR.
Is this still true? I’ve looked at several PAR approach charts in the military AIP# and they all appear to use QNH.
I instruct at three airports
a) Only uses QNH. There is a positive check/readback of QNH when switching to tower, both VFR and IFR. On instrument approaches, there is also a readback of the procedure minima beforehand. The only other pressure setting I have heard used is Standard/Flight Levels for airways traffic. The first time a student uses QFE is on a landaway.
b) Uses QNH and QFE, the latter for circuit and arriving traffic, the former for departing and all instrument traffic. You can be given the QFE when 10+ more miles away, leading to arriving and departing traffic being on slightly different settings and potentially misinterpreting reported altitudes from nearby aircraft. I use QNH for all IFR but instruct using QFE in the circuit partly due to standardisation with other instructors and partly because that’s how that airfield operates.
c) Uses QNH, QFE and RPS (Regional Pressure Setting). RPS in particular annoys me, given the relatively close proximity of controlled airspace based on QNH. It is religiously issued when departing the zone, religiously readback and studiously ignored. We stick to QNH including for circuits.
Guess which one is the military airport? The first. The last is manned by very capable FISOs who follow CAA guidance.
The good news is that RPS is to be partly phased out from January. It seems that the infringement lobby within the CAA have figured out how counterproductive it is and managed to sway their colleagues to agree this change. I’d like to see it removed completely from the PPL theory syllabus and consigned to the dustbin. The added complexity just confuses students unnecessarily.
The use of QFE is so ingrained and endemic in the UK, especially in PPL flight training, that it will take time and effort to transition to the same solution that the rest of the world uses. The advantages would include that pilots could use the same QNH procedures when landing at grass fields/unmanned airfields, much less confusion about which setting was in use, simpler R/T for pressure settings, compatibility with the rest of the world so its not a surprise when venturing abroad.
*David C
Yes it is true Use of QFE is standard at all U.K. military airfields , some will allow the use of QNH because of the high number of civil or foreign military traffic but for them it is not SOP.
After thirty + years flying civil commercial transport I find U.K. light aviation and the RAF stuck in an archaic altimeter setting regime that is prone to errors but as an instructor at an RAF flying club it is the system I am stuck with so I have to teach ways to mitigate the risks involved with a single pilot changing altimeter settings at high workload phases of flight.
Forty and some years ago we also made use of QFE when flying aerobatics, giving you a direct reading of how much air remained below…
But AFAIK, even this has been dropped nowadays, leaving its use as a sign of originality more than anything else 
I have done PAR in UK RNAS base, they gave both QNH and QFE now (I was not able to listen to their UHF ATIS but I suppose they broadcast both?), I think only MATZ VFR overhead transits that are done “2000ft overhead on QFE” with no QNH
Yes it is true Use of QFE is standard at all U.K. military airfields
I instruct regularly at a large UK military airfield. I have never used QFE there nor even heard it mentioned, so I can’t accept this is standard at ALL UK military airfields.
I accept that other military airfields may still use it, including for MATZ transits. I’d like to see some switch away from that to standardise on QNH but appreciate that not everybody shares this view. However I have met several ex-fast jet pilots, now instructors, who would share your opinion that QFE should be phased out.
