Without getting the books out, as I recall the QFE will be calculated for the highest point on the aerodrome and if the elevation of any threshold is 7ft or more less than the highest point on the aerodrome a threshold QFE will be calculated and passed by ATC if that runway is used
The elevation for which the QFE is given is the highest point on the runway(s). Thus landing on an undulating aerodrome would have the altimeter reading zero or less depending on what part of the runway(s) was the highest.
The use of a threshold QFE only applies to instrument runways and for straight in approaches.
This complicates things further because there will be a different QFE required if one cancells a straight in approach late in favour of a circling (say a wind shift)!.....more cheese holes lining up!
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Blacksheep, it is impossible to set the Kathmandu QFE on most altimeters so the argument does not apply.........other than the posibility of having a pilot who normally lands with the alitimeter reading zero forgetting that that arrival will happen at 5000ft.....but I guess that the nearby mountains would prevent wreckage from reaching the runway!
Regards,
DFC