Nina : NO COMMS DOES NOT MEAN NO SURVIVORS - KEEP SEARCHING

[ianat182]

Do all EPIRBs broadcast on the same frequency now, I seem to recall that there was a recent change from the original and that aircraft had changed theirs; is it possible that this could be a reason for no signal pickup?

ianat182

 

[TradewindSailor]

EPIRBS are setup to transmit on common frequencies 406, and 121.5 Mhz .... the 406 MHz is the one for satellite distress message, the other for homing. The 121.5 MHz is no longer onward transmitted by the satellite.

As far as I am aware the homing signal is only generally detected by the SAR on line-of-sight.

Unlike SART, I don't think general seagoing vessels are equipped to be alerted to or home in on any of the EPIRB frequencies.

I do find my lack of understanding of how such an important piece of safety equipment works very frustrating.

I look forward to being educated!

Edit .... Sorry, forgot to answer the question. As of 1 February 2009 Cospas-Sarsat satellites no longer detect 121.5 MHz distress beacons. I believe Nina's to be an older type 406 Mhz EPIRB that doesn't transmit a GPS position, but I don't know any more that this. Therefore the most likely reason that we haven't heard a distress call is that the EPIRB didn't work or couldn't be operated for some reason.

 

[ytd]

Yes they all broadcast on 406. Many years ago they just broadcast on 121.5 and you relied on a passing aircraft to report the activation. None of this type would be operational because their batteries would have long ago corroded away. When satellites were introduced on 406 the positions generated were not that accurate so they kept the 121.5 signal so that SAR aircraft could home in on it. The latest EPIRBs have inbuilt GPS and transmit their position which is relayed by the satellite so the homing signal is a bit redundant now. I'm surprised the nina had only 1 EPIRB and it was the older non GPS type. Given their low cost and high reliability they are the cheapest insurance on any ocean crossing.

 

[TradewindSailor]

YTD's response is a little misleading.
Firstly by no means are all current marine quality EPIRBS come with GPS. Also there is no guarantee that the EPIRB's GPS will generate a fix, and certainly not for the first few emergency message sets. Therefore the 121.5 MHz homing frequency is very important.
Secondly the homing frequency is very important for the SAR team to locate the survivors without having to refer to the ground station for the latest known GPS position.
I also see no reason to insinuate that Nina's choice of EPIRB was somehow substandard. To most yachtsmen it would appear to be up to date. It is only whilst doing this research that I became aware of the deficiencies in the older units self-test procedures.... and I am still not aware of what EPIRB Nina has.

 

[TradewindSailor]

There's another posting on the facebook site showing where where the Nina or the life raft could have drifted.
This area is not where the experts say she would end up ......

https://www.facebook.com/photo.php?...533.1073741829.562485157120703&type=1&theater

If they are in the life raft they must be found fast ...

 

[Deleted member 36384]

All those other abandoned yachts drifted westwards. That is a very powerful image, which as you imply, the experts should search in that direction.