Originally Posted by
DOUBLE BOGEY
CGB the MSD you refer to alows for PEC aircraft position error, equipment tolerance and the GA manoeuvre.
John Eacott are you seriously suggesting that flying the GS at the very few international airports that have ILS in Oz you will be less than 200 feet MSD during the approach! I know its hard and trendy to accept greater risks down under but really!
You guys can hypothesise all you like. For me I will execute an immediate GA if my RADALT tells my I am at 170 feet MSD during an ILS where the state minima is 200 feet.
For all the usual heros out there that want to be as low as you can and think you can stay safe...good luck.
DB
I'm not at all sure how you have devolved such a hypothetical from what I said. I have tried to point out (along with cows getting bigger) that using the rad alt will not give an accurate height above the airfield datum nor the threshold when used (as seems to be the inference here) as a warning at the 200ft point on the GS. The land under the aircraft at that time may be lower (as in the the case with many ILS airports here, not just international) or higher, and therefore you will not get a 200ft radalt warning at that point.
I have
not said that you will be below 200ft at the appropriate point of the approach. Methinks you do protest too much and not read what is written, including Boudreaux Bob's link to the Jepperson decode which firmly rebuts the use of the radalt. In the same way that you misread my explanation of the +50ft penalty when a PEC is not available
