If, as has been said, the 10DME holding fix is only 7NM from the MAPt., the nominal maximum height gain possible is, indeed, 1064FT. But a Pans Ops procedure design does not assume that the aircraft will start to climb immediately upon reaching the MAPt. Nor does it even assume that your DME equipment will show you the MAPt at precisely the right point.
It allows a fix tolerance area within which your DME will indicate the distance appropriate to the MAPt. Then the design assumes that it'll take a bit of time for the pilot to recognise the position (3 seconds at final approach TAS, with tailwind, is the usual allowance). Then a further 3 seconds for the pilot to react and start cleaning the aircraft up.
All up, the whole thing came easily come out to a mile or more before the procedure can assume that the aircraft is climbing away at 152 FT/NM. On the assumption that you will have 6 miles available for climb, the maximum height gain would be (6 x 152) 912FT.
Now for some "reverse engineering" for a moment. As 1400FT is the MSA and you have to reach that before you can do any necessary manoeuvring to enter the 10DME holding pattern, we have a discrepancy of (1400 - 912) 488FT. What is the MDA for this approach?
I'm thinking that the lowest it could possibly be is around 450FT. It's probably somewhat higher than that but, if it IS 450FT, there's a (488 - 450) 38FT discrepancy. To gain this additional height, the aircraft needs a further 0.25NM so, in effect, the aircraft could be 0.25NM beyond the 10DME holding fix by the time it reaches 1400FT.
But that is only part of the problem. The procedure design applies a fix tolerance at the 10DME position. This fix tolerance could mean that you reach 10DME where you are supposed to, or a bit before it, or even a bit after it. This won't make any difference to you when you fly the missed approach, but it can make a lot of difference in the design for it - there must always be enough distance available for climb to the safe manoeuvring altitude.
If the MDA is significantly above 450FT, one would think that there is plenty of distance available for climb to 1400FT. Thus, without knowing the location or the approach, I begin to wonder if there is some kind of airspace limitation, like maybe a TMA boundary that's close by.
[ 27 October 2001: Message edited by: OzExpat ]