why 406 beacons are bad

[SABRE17]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

[Spaceman3750]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

You still have that ability, the signal is just weaker.

[SABRE17]

allow me to direct you to the FCC attempting to get rid of the 121.5 capability

http://www.aopa.org/advocacy/articles/2012/120112elt-proposal-would-not-affect-availability.html

basically no NEW models can be made 121.5 meaning a phase out has in fact been initiated.

[Spaceman3750]

You understand that 406MHz beacons have a 121.5 homing signal transmitted at 500mW, right? The way I read this article, the FCC is trying to stop the sale of 121.5MHz-only beacons (a good thing, given that SARSAT doesn't listen for it any more), not 406 with a 121.5 homing signal.

If it only took them three hours, I'd say that's doing alright. Furthermore, the coordinates SARSAT gets is only as good as the GPS on-board the 406 (and many aren't equipped with GPS at all). Better GPS chip = better coordinates to SARSAT. No GPS chip = SARSAT takes a WAG, which is probably what was going on here.

[SABRE17]

two people died of exposure, before rescuers could get to their actual location, the coast guard helo could have been right on top of the plane if it had a 121.5 beacon...

not going to trust my life to some chip, furthermore, after being on several searches, every set of GPS coordinates we've been given, have been wrong, by a lot. 

[sardak]

allow me to direct you to the FCC attempting to get rid of the 121.5 capability
http://www.aopa.org/advocacy/articles/2012/120112elt-proposal-would-not-affect-availability.html
basically no NEW models can be made 121.5 meaning a phase out has in fact been initiated.

You've misread the change. From the FAA document:
1. This notice announces the FAA's intent to cancel TSO-C91a, Emergency Locator Transmitter (ELT) Equipment.
2. The effect of the cancelled TSO will result in no new TSO-C91a design or production approvals.
3. However, cancellation will not affect production according to an existing TSO authorization (TSOA). Articles produced under an existing TSOA can still be installed according to existing airworthiness approvals and
4. applications for new airworthiness approvals will still be processed.
5. This action does not impact operation of TSO-C91a ELTs, and these ELTs will continue to satisfy the 14 Code of Federal Regulation (14 CFR) § 91.207 ELT equipage requirement.

In other words, existing models of 121.5 MHz only ELTs can still be manufactured, sold and installed. If you want to design a new super-duper 121.5 only ELT that's never been TSO-C91a accepted, you're out of luck.

AOPA backs this proposed change and it is has been the biggest opponent to requiring 406 MHz ELTs. It is in favor of this change because the change does not require aircraft owners to replace their 121.5 beacons with 406 ones.

406 MHz ELTs are TSO'd to C-126. This TSO requires them to have a 50 to 400mW 121.5 homing signal. EPIRBs and PLBs sold in the US are also required to have a 121.5 homing signal.

If the beacon on the aircraft being searched for didn't have a 121.5 homing signal then either the beacon was faulty or it was not a model authorized for sale in the US. The Coast Guard is equipping all its aircraft and vessels with 406 DF equipment.

As for the GPS coordinates being off, that has nothing to do with the beacon, but the quality of the signal being received by the GPS in the beacon or the one connected to it externally. Not all 406 beacons have an internal or external GPS, in which case the location is Doppler determined, just like position was determined for analog, no GPS, TSO C-91a ELTs. Of course, Sarsat stopped listening to these old beacons in 2009.

As for "every set of GPS coordinates" being "wrong, by a lot," were they really GPS coordinates or were they Doppler derived locations? The Sarsat system spec states a minimum of 80% of Doppler derived coordinates are to be accurate within 20km (12 miles).

Mike

[EMT-83]

The 406 beacon got rescuers to within 10 miles of the crash site. Remember the days of 121.5 where each pass of the satellite put the signal on the other side of the state?

[TrevDog]

two people died of exposure, before rescuers could get to their actual location, the coast guard helo could have been right on top of the plane if it had a 121.5 beacon...

not going to trust my life to some chip, furthermore, after being on several searches, every set of GPS coordinates we've been given, have been wrong, by a lot.

Ok grandpa be sure to turn off your computer too and use snail mail.

All 406 MHz ELTs also have 121.5 beacon. Everything I've read through tests and actual emergency is that 406 beacons are very reliable. If a crash is so bad that the more powerful 406 MHz could only give last know position. Chances are that a 121.5 could not even be heard.

Or the Coast Guard is relying too much on the 406 gps coordinates and not even trying to DR 121.5

[RiverAux]

A three-hour find for an airplane that crashed into the water?  Seems like it would have been a miracle to find a target in that situation and I'm surprised that the beacon was transmitting anything at all. 

[Duke Dillio]

I used to live on Cape Cod BITD...  Sorry to hear that those poor souls died.

I personally think that they should have launched new SARSAT satellites instead of just abandoning the system altogether.  With today's technology, I'll bet a new SARSAT could locate the beacon, take a picture of it, and walk you right onto it...

[sardak]

personally think that they should have launched new SARSAT satellites instead of just abandoning the system altogether.

Uh, they didn't abandon the system. The most recent launch of a satellite with a Sarsat-Cospas payload was last month and there are three launches scheduled in 2012, with more beyond this year. There are currently six operational satellites in the LEOSAR (Low-Earth Orbiting) and five in the GEOSAR (Geosynchronous Earth Orbiting) systems.

The next generation system, MEOSAR, is already in development with initial operational capability planned for 2015. MEOSAR puts the Sarsat-Cospas packages on mid-Earth orbiting (MEO) navigation satellites - GPS, Galileo and Glonass. There are already nine GPS satellites in orbit with the packages undergoing test and evaluation. Return link (two-way comm) is an optional capability of MEOSAR. The US segment of this is called the Distress Alerting Satellite System (DASS).

http://searchandrescue.gsfc.nasa.gov/dass/index.html

http://www.sarsat.noaa.gov/future.html

Mike

[lordmonar]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

Quite possible.....Assuming that the 406 did not have the GPS option...then the search area is a circle is 5KM (or 3 miles)...add some drift due to wind.  10 miles is not too far gone.

If it was equipted with the GPS option....it should be updating the position all the time.

Now here's the kicker.....when the equipment quits (sinks, burns, run out of power) it is gone....even if you have 121.5.

So let's look at the benifits.

Inital contact....121.5 before it was turned off...had a delay of 4-6 and up to 12 hours BEFORE they even had a fix to give to rescurers....  406...10 minutes........now that 121.5 is turned off......unless you are interfering with ATC or someone happens to be monitoring 121.5 you are screwed.

Winner?  406

Next.....121.5 gave you a 20KM radius search area.......406 gives you a 5MK radius...add GPS and you get 3 meter resolution.

Winner?  406.

False alarms......121.5 had to be seached by hand....406 can be resolved with a phone call from AFRCC.

Winner?  406.

It is a shame these people died......but the technology did not kill them.  If they were using 121.5 they would not have been better off.

[SABRE17]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

[Spaceman3750]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

You are certainly entitled to your opinion, however I'm not sure your opinions are based on today's operational reality.

[lordmonar]

Ability for ELT to be honed down to precise location:

Winner: 121.5

NO need for special equipment beyond an LPER

Winner 121.5

Ive even seen 406 beacons advertised WITHOUT the 121.5 honing ability, what's the use in that? nothing if your dying of hypothermia in the ocean while coast guard and state assets are only a mile away. (search initially started in the right area, only to be led the complete location by the magical 406 beacons GPS coordinates.)

quite frankly If you have a beacon without 121.5 capability in it somewhere, you're nuts.

keep a couple flares handy too...

the 406 has both of those things.  You don't really understand what the 406 is all about. 

[rustyjeeper]

Technology changes and we need to learn to accept the change. The 406 beacons do tend to leave us out of the equation which is unfortunate, especially in the area in which I live. The Coast Guard notifues local LEO's and Fire Departments but CAP was never involved. Even if we had been involved in this search, the outcome would not have changed. CAP does not and will not "self deploy" any longer as it used to long ago those days are gone. In reality if MAWG had called for a mission by the time and IC was called and teams alerted and deployed the end result would be the same.

The 406 does it's job and most of those also have the 121.5 capability; which still keeps us in business to a limited extent. Me, if I had an aircraft I would want the 406, and if I were in your shoes I would also have the 121.5 ELT as a backup just in case. Redundancy is a good thing

[lordmonar]

The 406 does it's job and mostALL of those also have the 121.5 capability; which still keeps us in business to a limited extent. Me, if I had an aircraft I would want the 406, and if I were in your shoes I would also have the 121.5 ELT as a backup just in case. Redundancy is a good thing

Fixed it for you.

[RADIOMAN015]

For the last 3 hours I've been listening to the search for an aircraft here on Cape Cod, I noticed that coordinates given by the aircraft's beacon were almost 10 miles from where they eventually found the pilot... the Coast Guard had several GPS coordinates that all turned out to be duds, it eventually took a citizen calling the Fire Department saying he saw debris in the water. where they eventually found the remains...

I think its safe to say Id like the hone in ability of 121.5 to save my life...

Some radio monitoring hobbyist reports indicate that public safety & the local CG was notified immediately when the tower/approach countrol lost contact with the aircraft.
USCG had 2 water craft, 1 Falcon Jet, & 1 Helicopter at the Scene searching.  Also the USCG Aux had a plane respond to the area. Additionally, State Environmental Police responded with at least 1 or 2 water craft.   Check the video out at:
http://www.necn.com/01/15/12/Coast-Guard-Were-just-happy-to-bring-clo/landing_newengland.html?blockID=631976&feedID=4206
Looks like the sea was not very smooth out there.   Also there were snow squalls in the area right at the time the aircraft disappeared.  Note in the video the survival time in the water without a proper insulated suit.

I don't think CAP was even alerted to provide any assistance for this response.
RM
 

[RiverAux]

Report I saw said that it crashed on the beach and if that was the case I withdraw my earlier comments.

[jpizzo127]

It's my understand that the 121.5 tone from a 406 is very weak and useless to any ground team beyond 1/2 mile.

Is this correct?