Circling Approach MDA in brackets omitted from GPS/DME Arrival charts.

[Centaurus]

Amending DAPS and noticed that for all charts where the circling minima is shown for various aircraft categories the actual height above aerodrome reference point of the MDA is included in brackets. Presumably there is good reason for this and one can guess that it aids situational awareness and also helps when looking at cloud ceilings versus MDA.

Yet - the same information (MDA in brackets) is omitted for all GPS or DME Arrival charts and only the height above sea level MDA is published. As all DME and GPS Arrivals usually end at the circling minima, I wonder why the bracketed information is excluded? Any ideas?

[123567]

Sorry can't help you there?

New Zealand GPS charts show both QNH and AGL in brackets minima. :ok: :ok:

[Chief galah]

Possibly poor quality control in the proofing phase?

Like the new Essendon RNAV approach charts for rwys 17 and 26 which have different circling minimas.

Not correct for a civil field I'm told.

CG

[150Aerobat]

Also, whilst we are in a curious mood; why do approach charts for airports with no way of obtaining an accurate QNH (ie AWIB etc) have the MDA greyed anyway? Someone told me it was in case they put an AWIB in, but in that case they'd amend the chart adding the AWIB frequency.

Looking at an example of a DME/GPS arrival, it's almost like they just didn't have enough room to put both figures. I'm an IFR newbie, so perhaps I'll get used to it, but I don't like the discrepancy because when only one number is published, it leaves a potential element of doubt as to which one it is, on QNH or AGL. Another benefit of including the AGL figure in the MDA box is that it's easier to compare it to the TAF cloud ceiling figures without having to do any calculations.

[Wheeler]

Aerobat, I think you don't necessarily have to get an accurate QNH from an AWIB. A suitably qualiified/approved person on the ground, no doubt using suitable/approved equipment can tell you.
I think some of the airlines sometimes have someone at CTAF's who can give them all sorts of useful information. Pity they won't talk to anyone else though.

[turbantime]

Most places I fly in and out of have an AWIS but no AWIB, so you can ring up the AWIS from your phone before shooting the approach and use the actual QNH minima (I have Jepps). That 100ft has allowed me to get in a couple of times!

P.S. I don't use phones when hand flying in IMC, the autopilot's used for that.

[150Aerobat]

I never said the accurate QNH had to be from an AWIB. In country bumpkin Victoria however if you're going to get realtime QNH that's what it will be from. I have never in my time heard anyone provided with QNH at a CTAF or MBZ by an approved observer on the ground. How often does that really happen in reality?

I wish some of this dough we seem to blow in Aus aviation on departmental red tape could be spent on more widespread implementation of weather reporting stations including ceilometers. Now that would really actually do something for safety.