27/09
If I was swearing at you I would have used the word fcuk, fcuking, fcuked or something similar. In any case any statement of willingness to be below LSALT/MSA on DR (as you have admitted was an incorrect statement) most certainly does require head shaped holes in the wall!!!
I am happy to admit when I'm wrong. Don't defend an incorrect statement.
The emoticons are my frustration that people are willing to forego a twist of the knob and pressing a couple of buttons to go that little bit further to make sure they will be able to complete the approach rather than having to execute the missed approach halfway through.
From the CASA GNSS course;
for most phases of flight the GPS receiver will provide an immediate annunciation of a loss of RAIM capability. The exception is five minutes following passage over the final approach waypoint of a non-precision approach. During this time, a loss of RAIM annunciation will be inhibited. GPS navigation may still be possible during this RAIM outage.
The GPS receiver automatically performs an approach RAIM prediction just before passing the final approach waypoint and will only enter approch mode if RAIM at the 0.3nm horizontal integrity limit is predicted to be available from the final approach waypoint to the missed approach waypoint.
Still don't believe that is correct?
Again...
Agreed, the NAIPs prediction is more accurate, however where do you think the GPS receiver is going to predict RAIM availabilty from? Would it not be safer to know that the receiver is not going to sequence onto APPCH mode before arriving at the final point?
The "requirement I mention" is a CASA requirement. It is on the test form as a requirement. Regardless of my personal opinion, it ain't my sandpit, I just have to play in it.
I never ever said I would commence/continue an approach if the RAIM prediction said RAIM would not be available. Show me where I said that.
But aren't you saying you don't need to check RAIM before commencing an approach?
You have said the receiver will continue to navigate while it inhibits the RAIM warning,
meaning an approach can be completed and if necessary missed approach can be carried out in DR mode.
And then,
Firstly I used the wrong terminology, a GPS doesn't go to DR mode with just a loss of RAIM, it will navigate the same accuracy as before, but now it cannot ensure it's accuracy/integrity.
Want to try again?
The prediction checks for RAIM at the APPCH mode tolerance (0.3nm) with a 15 minute window either side of the predicted time of arrival at the missed approach point. When you commence the missed approach, the receiver reverts to TERMINAL mode (1.0nm RAIM limit) to enable you to safely complete the missed approach. You will have been in TERM mode from 30nm out from the final destination of your GNSS flight plan.
If you want to keep going during an approach when there is anything less than the required integrity available is suicide. Any warning of RAIM requires an
immediate missed approach.
The only thing I can't work out is why the approach inhibits an actual loss of RAIM? Trying not to distract the pilot? Anyone?
