121.5 Emerg Freq.

[tactical71]

Hello

I have an older PLB that operates on 121.5. Do commercial aircraft normally monitor this freq during normal operations.

Thanks
Gus

[blueloo]

Yes we do.

[waren9]

But we cant tell where its coming from or how far away it is. If your question has more than idle curiosity behind it, I highly recommend you spend some time here:

AMSA Beacons Information

[LeadSled]

tactical 71,
How about thinking strategic, how much is your neck worth.

A GME or similar pocket sized 406 beacon with GPS can be had for around $500 or less in a boat shop, add $100 from an airport shop.

In Sydney, that's about a night out for four people at a mid-range eatery, if you add in a couple of rounds at the pub before and after.

Tootle pip!!

[AerocatS2A]

We do, and we can tell where it's coming from, but not how far away it is (we could easily work locate it though just by homing in.) The 406 beacons are far better. Not only do the authorities know where it is but they also know who it belongs to. The 406 beacons still transmit on 121.5 so you get the best of both worlds.

[MyNameIsIs]

Yes 121.5 is monitored.

Don't rely on an old beacon to have you found. Just get a 406 w/GPS. It costs a little bit but if it saves your life one day you will be glad you spent the money.

[Skynews]

Commercial aircraft, normally do monitor and normally cannot tell which direction the beacon is located, and have a rough idea of distance only. ( strength of signal and aircraft altitude, detuning are our only hints)

It is not easy to home as we quite often don't have fuel available to complete the task.

[go_soaring]

This is what I use for gliding, it also has a tracking feature (logs a point every 10mins, and posts to the web). Great for general interest really, and excellent for safety. It has a few buttons that send other messages, 1) OK message, 2) OK, but send help (from a glider pilots perspective: "I've landed in a paddock, I'm OK, but send a road retrieve"), 3) Custom message, 4) 911, (emergency, send all services!).

http://www.findmespot.com/

I bought mine from: SPOT Satellite Personal Tracker $249-, for memory the tracking feature was another $120/yr.


go_soaring! instead

[Fly-by-Desire]

Commercial aircraft, normally do monitor and normally cannot tell which direction the beacon is located, and have a rough idea of distance only. ( strength of signal and aircraft altitude, detuning are our only hints)

Is there some sort of 'rule of thumb' as to how far away the beacon is by clarity of signal?

[ampclamp]

Very difficult to tell with variables in terrain, location in that terrain, battery condition etc.To the best of my knowledge commercial airliners dont have directional antenna or signal strength indication beyond received audio on VHF.

[ControlLock]

You can use a rough rule of thumb for distance as follows.
If the signal is at sea level and you are at F290 (29000') then VHF distance of signal is roughly = Square root(1.5 X 29000) = square root (43500) = 208.5NM

You can also bank the aircraft either side, if you know where your VHF antennae are located on your aircraft, to determine if signal is to Left or Right side of aircraft.

Easier method is to buy 406MHz with inbuilt GPS locator.

[ozbiggles]

Common to hear ATC asking a/c when they hear the signal/lose it, squelch on/off. RPT don't have the fuel to do aural homing for any longer as for reasons mentioned it takes a long time.(unless its known life is in danger). All they are trying to do is narrow down the area for the search a/c which has to get there and then start the search proper.
I've done a few starting off at low level. Its not exact and it wastes a lot of time if you're bleeding.
Get the 406, it will save hours ..... which could be your life

[VH-XXX]

As much as they say to throw them away, the last part of the search is conducted with directional finding equipment on 121.5 anyway, so I'll be keeping my old one as a backup.

[NZScion]

Originally Posted by VH-XXX

As much as they say to throw them away, the last part of the search is conducted with directional finding equipment on 121.5 anyway, so I'll be keeping my old one as a backup.

Yeah great, that will probably give two conflicting signals on 121.5 just when someone arrives overhead to find you, just like when we accidently step on one another on normal VHF comm freqs.

You'd be far better off throwing your old 121.5 in the rubbish (and for god's sake disconnect the battery before you do this so people don't end up initiating SAR action ending at the dump) and relying on your 406 to give a better signal, baring in mind that most 406 beacons also transmit a homing signal on 121.5 MHz, and that some have the ability to also transmit a GPS position, which turns "Search and Rescue" into "Get to and rescue".

[MyNameIsIs]

You'd be far better off throwing your old 121.5 in the rubbish (and for god's sake disconnect the battery before you do this so people don't end up initiating SAR action ending at the dump)

Do NOT do that.

Hand your old ones in to either the Police (a responsible authority), AMSA may take them, or even a place like Battery World as they will dispose of them properly for you- they even advertised it I believe.
It is the only real way to garuntee that your old beacon is 'safe' when it is out of your hands.

[Icarus2001]

the last part of the search is conducted with directional finding equipment on 121.5 anyway

Not really. Dedicated SAR aircraft have 406 mHz homing equipment as well 121.5 mHz.

[VH-XXX]

That's right, "dedicated" aircraft.... Lucky to get one of those when you need it, unless you are a government minister and the top secret Airvan is around.

[tactical71]

Thanks all.

And in relation to some of your comments regarding spending the extra money on getting a 406Mhz beacon. Well I would if I was relying on one. But Im not. I just happened to be given an old one that still works and was simply curious to know if it is still monitored, so "in the unlikley event of an emergency" on my farm, I can activate it as an added extra to a 000 call. But its NOT being relied upon for anything.

And as for $500 being a night out in Sydney, well, thats why I dont live in Sydney anymore!!! $500 is a great deal of money to some of us, especially someone who is raising a family on a single income.

Thanks for all your responses. Much appreciated

Cheers.

[Grogmonster]

Facts

Tactical,

I have read above quickly so apologise if I duplicate. These are the facts. The 121.5mhz beacon is no longer monitored by satellite. This means you will have to wait for an overflying aircraft to hear the signal. As they are usually quite high the area of probability could be hundreds of kilometers in any direction meaning you will be long gone before being found. All 121.5mhz beacons are investigated and because there can be no triangulation of satellite signals the aural homing can be very lengthy and expensive. It is true that the new 406 beacons use 121.5 as well but the new beacon narrows the search area down to a few kilometers and in some cases it gives the exact location, if GPS enabled, meaning the rescue service comes right to you. So in closing keeping an old 121.5mhz beacon just in case is like leaving a note on the kitchen table that you have gone fishing without a date and location on it. My advice is get rid of it and buy a new beacon.

Groggy

[tactical71]

Thanks Groggy for you very informative post. As I said earlier, I simply wanted to know if commercial aircraft still monitored the freq. and ive been given a resounding YES! Im fully conversant with the operation of 406 Mhz PLB/EPRIBs and should I even be venturing out into the unknown wilderness, I will take one with me.

Thanks again to all. Lets finish this off now!

Cheers
Gus