Depends whether you're on the AIS end or the SAT end 😉.

Your recollection is correct, IIRC it was originally developed for collision avoidance in coastal approaches and in to harbour. Like all technology its use gets extended. I am not aware of any modification required to a ship's AIS for it to be tracked by satellite. Best if it is a Class A unit though.

Concentric

I don't know the SAR fit for that S92, but I'd be surprised if it didn't include AIS. However whether it would have been selected for display is another matter.

Again, even with a beacon, the crew would have needed to be operating the radar in a beacon mode to benefit.

Not sure what the SOP would have been with regards to those items during such an approach.

The thing I can't get my head around is either

1) why there was no terrain warning.
2) if there was why it was too late or ignored.

My experience out of long time hosting of VHF AIS RX that standard coverage is 40 km between the islands. On open 80-100 km (LOS) for small crafts and in some extra summer propagation cases can go up 1500-1800 km. Location Mediterranean sea.
For low flying objects much better than ADS B or Mode A & C MLAT (have them too)

Did you see my comments earlier in the thread, that state that for the Mk XXII EGPWS the look ahead alert envelope shrinks below 100 KIAS and is inhibited below 70 KIAS? I'm not saying that is what happened, but it lends itself as an explanation.

Page 17: http://skybrary.aero/bookshelf/books/3018.pdf

Re SAR fit for Irish CG S92s - they had (2014) Saab R4 AIS at Winch Op position.

The following link may be of interest. Irish Coast uard is part of Dept. of Transport
S-92A Technical Details | DTTAS Department of Transport, Tourism And Sport

Just to note. The R4a is not connected to any on board sensors (ie air data computers) so any speed data is calculated from the AIS internal GPS position changes. The AIS GPS antenna on the S92 is located on the tail pylon.

No, I believe the modifications had to be done to the satellites to allow them to pick up the specific VHF tx from the ships AIS - duplex channels of 87B and 88B I think.

that will be the GPS Rx but where is the VHF Tx aerial for the AIS?

Great idea to have the EGPWS disabled at 70 kts - just the sort of speed you are doing a trans down to the hover and possibly getting close to obstacles/land.

212 man. Sorry being a bit sloppy with my terminology. There are a number of conditions under which there is no FLTA protection. Similarly warnings could be inhibited. However the display should have had an unambiguous amber blob of terrain in their flight path. I can't fathom either the absence or misinterpretation of this.

I for one have done a bit of flying around with TAWS + MFD equipped helicopters in VMC and have often wondered why I don't get terrain warnings when I'd expect a warning was appropriate, and why I get warnings which I don't think to be necessary. I have a poor understanding of the logic being used in either case to warn, or not to warn. One of the IFR helicopters I was flying was fitted with the aeroplane version of the TAWS system (because it was cheaper) and that was next to useless in the helicopter operating environment.

I have come to the conclusion the system can't be relied upon 100% of the time, and if you're relying on it not to hit something, that reliance is not totally reliable.

VHF Tx just forward of the ramp on the belly.

Which is good for operation with satellite tracking in open water as the chances are there will be satellites below you. However not so good in terrain.

But also the time that you get most irritated by something telling you the fact that you're approaching the ground?

As far as I can tell, the map display should still have had the high terrain marked. If it wasn't i'm interested to know why.

Yes, it will.

But only if selected onto a display, presumably?

Yes, but assuming the wx radar is on the NAV MFD it will require the PFD to be set to ARC mode to show EGPWS (or vice versa depending on which requires the greater granularity) . That's how I set it up, but some operators like to revert to HSI mode for that nostalgic feeling of reduced SA.....

Thanks for the info, from your setup I presume there is no automatic popup with proximity to off airport terrain.

There is a pop-up mode which will appear on an MFD with PFD Arc or NAV set and, if none selected as such, will automatically change the display of one MFD according to a priority logic. However, I prefer to have the map there in the first place to avoid pop-ups!

The pop up mode is not a separate mode, it merely displays the terrain map when a warning is generated; so it will be suppressed in the same way as described above.

On another note, radar beacons display in the S-92A standard wx mode.