Briefing QNH in hPa

[Nealius]

Despite having mutliple aircraft that only work in hPa, we only get QNH in Torr and in.Hg. 

 

Oddly we get QFE in all three units, but QNH is the standard for setting the altimeter, not QFE.

 

Modules that can only use hPa:

 

-Spitfire

-Mosquito

-Bf 109 K4

-Fw 190 A8

-Fw 190 D9

-AJS 37

-Mirage 2000

-Gazelle

[Northstar98]

+1, and preferably, the unit of pressure present in the briefing should match the unit of pressure the aircraft uses (or just units in general).

[frostycab]

Unsure how this works. I know QNH is by far the most common reference in civil aviation, but is the same true for military flights?  Do fighters takeoff and land on QFE and use QNE in the air? Practically speaking, I can see QFE being a valid reference for landing aircraft given that operational requirements may involve landing at unfamiliar airfields that the pilot may not have charts readily available for.

 

Also, how do different countries' militaries vary? One might work on QFE, another on QNH.

[Nealius]

4 hours ago, frostycab said:

Unsure how this works. I know QNH is by far the most common reference in civil aviation, but is the same true for military flights?  Do fighters takeoff and land on QFE and use QNE in the air?

 

Western militaries are all QNH below TA. 

 

Quote

Practically speaking, I can see QFE being a valid reference for landing aircraft given that operational requirements may involve landing at unfamiliar airfields that the pilot may not have charts readily available for.

 

That would only work if the destination airfield is the same elevation as the departure airfield. 

[frostycab]

8 hours ago, Nealius said:

That would only work if the destination airfield is the same elevation as the departure airfield.

...and the local barometric pressure was the same.

 

My assertion was based on the idea that an operational airfield would have some sort of traffic control in place to pass the local QFE to the pilot. That being said, if such a situation occurred then traffic control could just as easily pass the field elevation to the pilot which would allow for an approach and landing using QNH, and any pilot will tell you that QNH is the optimal reference for maintaining obstacle clearance.

 

The thing is there are multiple methods that could all work, but no readily available source of information that I can find to denote which is used where, why and by whom. 

8 hours ago, Nealius said:

Western militaries are all QNH below TA. 

That's good to know, but can you elaborate a little for me, as I can envisage situations where things may not be so clear-cut. For example, would the TA be the local TA or would it be assigned to an entire theatre by command and planning specialists? The TA for much of the UK is 3000ft AFAIK, yet within the London FIR and other busier areas it's double that at 6000ft. 

 

I'm guessing that C&C assets such as AWACS would pass target track information using QNE at all times? If not then pilots would have to recalculate in the US every time a target passed through 18000ft. (In reality I don't see this as a huge issue, as local deviation from QNE rarely exceeds a few hundred feet on a good day, and 1200-1500ft on a bad one. Radar-equipped intercept aircraft don't need to know a target's altitude down to the last foot.)