Jonas wrote:
Is LOAN non-towered?
Yes, but there must be some kind of AFIS as the plate says that you need the local QNH.
Yes, but there must be some kind of AFIS as the plate says that you need the local QNH.
Maybe read remotely and given by Wien radar/information?
In France, you can use non-local QNH but on higher minima, in US you could adjust non-local QNH yourself based on NM distance
I am not sure what is the situation in other countries but I am sure 30QNH delta is better than no IAP at all
Ibra wrote:
In France, you can use non-local QNH but on higher minima, in US you could adjust non-local QNH yourself based on NM distance
This is in PANS-OPS. For non-mountainous terrain the principle is “when the altimeter setting is derived from a source other than the aerodrome, and more than 9 km (5 NM) remote from the threshold, the OCA/H shall be increased at a rate of 0.8 m for each kilometre in excess of 9 km (5 ft for each nautical mile in excess of 5 NM) or a higher value if determined by local authority.”
I am not sure what is the situation in other countries but I am sure 30QNH delta is better than no IAP at all
Unusual, as far as I’ve seen. But then many countries require an open ATS unit at the airport for instrument approaches and then the question is moot.
Airborne_Again wrote:
This is in PANS-OPS. For non-mountainous terrain the principle is “when the altimeter setting is derived from a source other than the aerodrome, and more than 9 km (5 NM) remote from the threshold, the OCA/H shall be increased at a rate of 0.8 m for each kilometre in excess of 9 km (5 ft for each nautical mile in excess of 5 NM) or a higher value if determined by local authority.”
Thanks at least no technical reason why it can’t be done as some calculations methods are already in the TERPS/PANS-OPS
Airborne_Again wrote:
But then many countries require an open ATS unit at the airport for instrument approaches and then the question is moot.
Yes the point is moot if you need an “IFR dude” to land but one of the quoted reasons is that you need someone on ground to give you weather data (QNH & VIS) before you can start an IAP 
Reminds me when I asked in UK why I had to re-PPR the second time when I already got PPR yesterday but we cancelled?
I was told, to quote: “we need to give you new QNH & wind by phone for your flight tomorrow morning”
In any case, as long as your alternate has official weather (e.g. x-wind, cloud, visbility, qnh) that fits the bill, you should be allowed to give a try your luck at destination even with zero weather data over there…
Most/many of the IAC charts for non towered airfields in France will tell you where to get the QNH. It is also another reason for the circle to land at untowered airfields. In case it is not clear when I write untowered I mean there might be no-one on site. It is not necessary to have a Flugleiter, AFIS, airport manager or any such personnel.
Some towered airfields become class G when no ATS is present, the IAP’s are still available unless otherwise stated . Such is the case even at larger airports (comparitivly speaking) like LFBH,
La Rochelle.
At the IAP platform you can set the altimeter from GPS; it will be very very close (probably 10-20ft). And if/once visual you don’t need QNH.
At the IAP platform you can set the altimeter from GPS;
So you mean it is legal to set QNH from the GPS when performing instrument approach?
Jonas wrote:
So you mean it is legal to set QNH from the GPS when performing instrument approach?
Not sure what is the answer? but in UK QFE approaches are legal (I have done few instrument approach at RAF Wittering, it’s PAR approach on QFE, between us I should have prepared those ones very throughly with Mil AiP paper prints for frequencies & minima within my hand reach not deep in my bag, I find out that SkyDemon & ForeFlight did not have those plates and Garmin does not have anything on the database )
The problem is that without QNH you don’t know if you are flying the 2D IAP platform or not obviously, the question of using “local QNH” is mostly about legality, practically, if you are flying 3D approach with SBAS or ILS dead on the cross with “GPS DA minima” (or radar altimeter DH if you are on Cat2/3 ILS), you won’t hit anything even with 1000ft delta between QNH altitude and GPS altitude
So if you can fly instrument approaches on QFE & Radar Altimeter heights, why not on GPS altitude? (maybe safer if you have fat fingers)
I didn’t know QFE approaches were illegal.
I thought they had just gone out of fashion with pilots and ATC because QNH was less cumbersome.
