406 vs 121.5 ELT (from Another crash in AK thread)
- Thread starter mvivion
- Start date
lowlevelops
SPONSOR
Montana
Not all 406s are equipped with a GPS or are coupled to an onboard GPS. The triangulation between satellites is far superior to the old system, but it is still not exact. I think an Air Force liason told me, with just the triangulation, you could expect to be within a 2Km radius of the target. Depending on terrain 12.5 square kilometers can still be a large search area and that is where the 121.5 DF part comes in.
Respectfully,
Respectfully,
spinner2
FRIEND
Montana
In another thread regarding the SPOT tracker I mentioned that I'd recently purchased one after being impressed with how well they work after watching a Cub friend fly from Montana to Alaska and back over a three week period. It occurred to me to include my SPOT tracking page on my online NOAA 406 beacon registration. So now if my ELT is activated SAR can go right to my SPOT page and see where the last hit was and when. Kind of like getting an Ntap trace from Center but without any delay.
One more tool in the SAR tool box.
One more tool in the SAR tool box.
mvivion
FOUNDER
Bozeman,MT
qsmx,
I guess I'd like to see "official" testing of the attenuation of a signal, but remember, NASA talked to the crews on the moon with less than 1/2 watt, if I recall correctly. All this has to do is communicate to a satellite---one burst, if GPS equipped.
AK-HUNT,
As lowlevelops noted, the initial one burst triangulation of a 406 signal is NOT that accurate. I have had SAR guys tell me how precise those coordinates are, but remember--typically, the SAR guys actually arrive on scene several hours after the first ELT signal is transmitted. That means that RCC has generally received several additional hits, and has therefore been able to refine the location better.
If you get really unlucky and the plane burns, for example, or sinks.....the initial 406 location will be sorta close, but as the man pointed out, searching that large a radius is still a challenge, and takes time.
Talk to a SAR guy, and they'll tell you all sorts of fairy tales about how precise the 406 beacons are, and it does seem they are an improvement, but they aren't magic, by any means, and remember that the SAR guys are out there on the point....not necessarily privy to what goes on the processing department.
So, we still rely on a 121.5 beacon to enhance the on-site locating of the beacon.
MTV
I guess I'd like to see "official" testing of the attenuation of a signal, but remember, NASA talked to the crews on the moon with less than 1/2 watt, if I recall correctly. All this has to do is communicate to a satellite---one burst, if GPS equipped.
AK-HUNT,
As lowlevelops noted, the initial one burst triangulation of a 406 signal is NOT that accurate. I have had SAR guys tell me how precise those coordinates are, but remember--typically, the SAR guys actually arrive on scene several hours after the first ELT signal is transmitted. That means that RCC has generally received several additional hits, and has therefore been able to refine the location better.
If you get really unlucky and the plane burns, for example, or sinks.....the initial 406 location will be sorta close, but as the man pointed out, searching that large a radius is still a challenge, and takes time.
Talk to a SAR guy, and they'll tell you all sorts of fairy tales about how precise the 406 beacons are, and it does seem they are an improvement, but they aren't magic, by any means, and remember that the SAR guys are out there on the point....not necessarily privy to what goes on the processing department.
So, we still rely on a 121.5 beacon to enhance the on-site locating of the beacon.
MTV
mvivion said:
That's what confuses me about all this stuff. YOU are telling us that the "SAR guys" say 406's are better and furthermore you say they are the ones "on point". BUT then you say don't believe them? (they are the ones coming to get me right?)
Maybe I'm just slow (so I've been told) but I don't follow that logic? Also, why do you refer to their reports as "fairy tales"? Do you mean they are lying or mistaken or both?
Have you heard any accounts of the 406 being LESS reliable?
Also, if the ELT burns or sinks relatively quick (in your example), the 406 would spit out some coordinates and the 121.5 would just make noise for a little bit. NO starting point, no search, no nothing. Right?
To your last statement; I find it hard to believe DFing a 121.5 in any sort of terrain is more precise than getting coords from the 406. My .02.
Anyway, back to my lurking.
fobjob
MEMBER
Salt Lake City, Utah
Bear in mind, that if your plane burns or sinks, it had better take longer than 50 seconds to do so, because that is how long it takes the ELT to spit out it's first data burst on 406. Also, it can take hours to develop an accurate position from a non-GPS equipped ELT being tracked by the low-earth orbit SAR satellites. (As opposed to the high altitude 406 data monitoring satellites, which may not receive anything if the elt antenna is damaged, or under the fuselage 50 seconds after the crash.) If you've ever searched for anything, then you know that the last hundred yards can be the toughest, so you need a homing signal that can be utilized by people on the scene.
mvivion
FOUNDER
Bozeman,MT
AK-Hunt,
I mean no disrespect to the SAR folks. My point was and is that they simply receive coordinates, and have the job of going to those coordinates and searching.
In that process, they often find the subject very close to the coordinates that they were given. My point was that this is GENERALLY because, while the SAR folks were mobilizing and flying out to the search area, RCC got two or three more "hits", every one of which further refine the coordinates. So, when a SAR helo arrives at a crash site, which happens to be very close to the coordinates that they were given, it APPEARS to them that the SAR/SAT system pinned the location VERY precisely, and many of them ASSUME that this is from the first "hit".
And, as fobjob points out, even with a 2km search radius, having a DF capability once close is essential. A 2 km search radius is HUGE, especially in tough terrain. Still far better than a single hit off a 121.5 would have been mind you.
My point is that there is a LOT of chatter out here about how these 406 beacons will locate you VERY precisely instantly for RCC, and that simply is not true, even in the best of circumstances. If the beacon continues to transmit, RCC will get more hits and those will help to further resolve the location solution, and after several hits, the location will be pretty precise.
So, I'm not badmouthing the 406 beacon--in many ways they are better than the 121.5 beacons. My point is to understand what they do and understand their limitations.
I called RCC in ANC and the one at Tyndall AFB, and the line I got from both was that the location they get from a 406 beacon was extremely precise on the first hit. That simply isn't true, even in the best of circumstances. It's better than a 121.5 hit. Now, understand that I'm guessing I was talking to some clerk who answered the phone....but there were posts on this forum stating that SAR personnel said essentially the same thing, and I've talked to at least one SAR crewmember who did.
I want a GPS enabled 406 beacon before I spend that kind of money on a new beacon. That way, the first "hit" will contain GPS coordinates, and hopefully, if the plane burns or???? SAR will have a relatively easy time finding the carcass....
In the meantime, I'll continue to carry my PLB, and hope that if I screw up really bad I'll still be able to deploy the thing. I also have a SPOT aboard, but don't consider it much of a help in such an event, but it's relatively cheap, and you never know.....
When Artex has their GPS connector approved, I'll order one and a 406 beacon from them. Till then, I'll try not to crash. 8)
MTV
I mean no disrespect to the SAR folks. My point was and is that they simply receive coordinates, and have the job of going to those coordinates and searching.
In that process, they often find the subject very close to the coordinates that they were given. My point was that this is GENERALLY because, while the SAR folks were mobilizing and flying out to the search area, RCC got two or three more "hits", every one of which further refine the coordinates. So, when a SAR helo arrives at a crash site, which happens to be very close to the coordinates that they were given, it APPEARS to them that the SAR/SAT system pinned the location VERY precisely, and many of them ASSUME that this is from the first "hit".
And, as fobjob points out, even with a 2km search radius, having a DF capability once close is essential. A 2 km search radius is HUGE, especially in tough terrain. Still far better than a single hit off a 121.5 would have been mind you.
My point is that there is a LOT of chatter out here about how these 406 beacons will locate you VERY precisely instantly for RCC, and that simply is not true, even in the best of circumstances. If the beacon continues to transmit, RCC will get more hits and those will help to further resolve the location solution, and after several hits, the location will be pretty precise.
So, I'm not badmouthing the 406 beacon--in many ways they are better than the 121.5 beacons. My point is to understand what they do and understand their limitations.
I called RCC in ANC and the one at Tyndall AFB, and the line I got from both was that the location they get from a 406 beacon was extremely precise on the first hit. That simply isn't true, even in the best of circumstances. It's better than a 121.5 hit. Now, understand that I'm guessing I was talking to some clerk who answered the phone....but there were posts on this forum stating that SAR personnel said essentially the same thing, and I've talked to at least one SAR crewmember who did.
I want a GPS enabled 406 beacon before I spend that kind of money on a new beacon. That way, the first "hit" will contain GPS coordinates, and hopefully, if the plane burns or???? SAR will have a relatively easy time finding the carcass....
In the meantime, I'll continue to carry my PLB, and hope that if I screw up really bad I'll still be able to deploy the thing. I also have a SPOT aboard, but don't consider it much of a help in such an event, but it's relatively cheap, and you never know.....
When Artex has their GPS connector approved, I'll order one and a 406 beacon from them. Till then, I'll try not to crash. 8)
MTV
SAR can fly to the crash site?? 
Just kidding. I think over the time I was involved, here in the NW on the Olympic Peninsula, the reason for the SAR type crashes was always weather and night time related. There was no "flying in" or searching by SAR. Of the five I can remember they never knew what hit them as they flew in at cruise speed at night and in the clouds in the mountains. Of the ten individuals involved there was only one survivor and she had to lay in the wreck with the "others" for the 24 hours it took (3?) teams to finally resolve the ELT signals bouncing all around. The ELT's all functioned as they should. The fender benders at the airport didn't require SAR. In real searches in rugged terrain in areas prone to low ceilings/wind ground crews will always do the work immediately following the crash and so ground locating signals will remain important. Lurking on some of these discussions about this subject has made me think the spot signal ( I only know about from reading here) along with a flight plan could be your best possible "out". One more thing, as I remember 10% of the GA flying was done at night and 50% of the fatalities happened at night. GA fatality numbers were the same as motorcycle numbers. Compared to the automobile ran seven to one. Don't know what that rate was compared to ie.: hours, miles fun factor etc.? Don't know if those statistics still hold or not. Side observation: four of the crashes I know about involved trees and all the aircraft wound up at ground level. I used to naively believe if crashing in the tall trees around here they would cushion your fall, I now think that to be a romantic idea along with weather related survival. Looks more like a 10 to 1 shot to me. Some on here talk about scud running. This conjures up to me a mental image of a heavy black bag and a lot of work ahead that I'm to old to have to do anymore.
Just kidding. I think over the time I was involved, here in the NW on the Olympic Peninsula, the reason for the SAR type crashes was always weather and night time related. There was no "flying in" or searching by SAR. Of the five I can remember they never knew what hit them as they flew in at cruise speed at night and in the clouds in the mountains. Of the ten individuals involved there was only one survivor and she had to lay in the wreck with the "others" for the 24 hours it took (3?) teams to finally resolve the ELT signals bouncing all around. The ELT's all functioned as they should. The fender benders at the airport didn't require SAR. In real searches in rugged terrain in areas prone to low ceilings/wind ground crews will always do the work immediately following the crash and so ground locating signals will remain important. Lurking on some of these discussions about this subject has made me think the spot signal ( I only know about from reading here) along with a flight plan could be your best possible "out". One more thing, as I remember 10% of the GA flying was done at night and 50% of the fatalities happened at night. GA fatality numbers were the same as motorcycle numbers. Compared to the automobile ran seven to one. Don't know what that rate was compared to ie.: hours, miles fun factor etc.? Don't know if those statistics still hold or not. Side observation: four of the crashes I know about involved trees and all the aircraft wound up at ground level. I used to naively believe if crashing in the tall trees around here they would cushion your fall, I now think that to be a romantic idea along with weather related survival. Looks more like a 10 to 1 shot to me. Some on here talk about scud running. This conjures up to me a mental image of a heavy black bag and a lot of work ahead that I'm to old to have to do anymore.
spinner2
FRIEND
Montana
mvivion said:
I'm not sure I follow this line of reasoning. The original thread that this one came from was about the Beaver last summer that was missing in Alaska with Park Service employees on board. A huge amount of time, dollars and peril were involved looking for this plane. Parts of it were found months later in salt water. I would think that if searchers had a track of the plane's route from the time it left on this flight until it crashed that the search would have been much shorter. And had there been survivors that they could have been rescued.
As it was they had very little to go on other than knowing where the destination was supposed to be and when they left.
I understand that the US Forest Service requires contractors to have a system like Spidertracks for all flights now. I wouldn't be surprised if the Park Service doesn't make that policy shift too. SPOT is a very similar, less sophisticated system.
My guess is that the part of the impetus for the FS making this requirement came from a C206 that crashed a few years ago on a short flight from Kalispell MT to Schafer Meadows carrying FS employees. The pilot turned up the wrong canyon in poor weather and crashed on a ridge high above the Middle Fork of the Flathead River. Aerial searchers found the crash site a couple of days later and saw that it had burned and it appeared there were no survivors. A day later the survivors made their way down to Highway 2 that runs along the river and the southern edge of Glacier Park. They were injured but alive.
S
StewartB
I'm compelled to point out a couple of things.
1) During MTV's "research", he calls two different RCC stations and is given a direct answer to a serious question. He dismisses those answers as "simply not true". Wow. Ask the guys who use the technology every day and dismiss what they say? How does MTV know more than the guys flying the rescue helicopters? Uniformed soldiers are lying to him? Why would they do that? The helo pilot I know says the initial position solution is generally within 100'. He actually flies RCC missions in Alaska for a living. MTV? Want his contact info so you can compare notes?
2) Use a PLB. In Alaska, the Air Guard will be the responders to an aircraft ELT signal. They have superior speed, equipment, and personnel to respond to difficult rescue situations in difficult weather. State Trooper's words, not mine. A PLB, since it is not aircraft registered, is the responsibility of State Troopers. The Troopers may ask the Guard to assist or they may choose to respond on their own but the Guard can't respond to any beacon other than aircraft ELT without dispatch from AST. No AST dispatch is required for aircraft ELT cases. That's a fact. MTV? Need the contact info to "research" that?
Most of you have read this thread and accepted what MTV has written as accurate. Please do your own research. Especially those of you outside of Alaska, because I have no idea who will rescue you guys or how they'll do it. Most of you are urbanites so the issue probably doest mean much to you. For those of you in Alaska? MTV has provided very bad information. Dangerous information. I don't care to argue but I care about your survival. If you'd like a couple of phone numbers to call RCC and the Alaska State Troopers yourself? PM me. I'll be happy to forward you on so you can hear for yourself what the folks that work in S&R have to say. I'm not selling anything or asking you to believe me. I'm asking you to be responsible for your own safety and for those passengers who trust you with theirs. Threads like this are supremely frustrating. Too much bad information is traded around like it's meaningful. Too many guys accept bad information as factual. Beware of what you read and be careful what you believe. Personal responsibility starts with you.
Stewart
1) During MTV's "research", he calls two different RCC stations and is given a direct answer to a serious question. He dismisses those answers as "simply not true". Wow. Ask the guys who use the technology every day and dismiss what they say? How does MTV know more than the guys flying the rescue helicopters? Uniformed soldiers are lying to him? Why would they do that? The helo pilot I know says the initial position solution is generally within 100'. He actually flies RCC missions in Alaska for a living. MTV? Want his contact info so you can compare notes?
2) Use a PLB. In Alaska, the Air Guard will be the responders to an aircraft ELT signal. They have superior speed, equipment, and personnel to respond to difficult rescue situations in difficult weather. State Trooper's words, not mine. A PLB, since it is not aircraft registered, is the responsibility of State Troopers. The Troopers may ask the Guard to assist or they may choose to respond on their own but the Guard can't respond to any beacon other than aircraft ELT without dispatch from AST. No AST dispatch is required for aircraft ELT cases. That's a fact. MTV? Need the contact info to "research" that?
Most of you have read this thread and accepted what MTV has written as accurate. Please do your own research. Especially those of you outside of Alaska, because I have no idea who will rescue you guys or how they'll do it. Most of you are urbanites so the issue probably doest mean much to you. For those of you in Alaska? MTV has provided very bad information. Dangerous information. I don't care to argue but I care about your survival. If you'd like a couple of phone numbers to call RCC and the Alaska State Troopers yourself? PM me. I'll be happy to forward you on so you can hear for yourself what the folks that work in S&R have to say. I'm not selling anything or asking you to believe me. I'm asking you to be responsible for your own safety and for those passengers who trust you with theirs. Threads like this are supremely frustrating. Too much bad information is traded around like it's meaningful. Too many guys accept bad information as factual. Beware of what you read and be careful what you believe. Personal responsibility starts with you.
Stewart
mike mcs repair
Registered User
chugiak AK
spinner2 said:
agreed
Night vision does not do any good (that I know of) in the clouds. A lot of the time we couldn't see the tops of the trees while searching. The sad thing about four of those I described is that they were only 100' or less from the tops of ridges. For two, if there had been no trees there wouldn't have been a wreck. My experience is in a certain area that had the FAA's attention for a long time here in Washington with bulletins etc.. There is a narrow corridor? between the mountains and the water of Puget Sound at Discovery Bay. All of these A/C were (I think) transiting from Seattle area to Port Angeles and if memory serves within 5 or 10 miles of each other. No one could understand the thinking that led to these accidents. Some of the theories centered around a pilots reluctance to transit over water at night in a single engine A/C and so "snuggling" up to the hills a little to close. I think (I really don't know) the VOR signals maybe had something to do with it as it seems to have stopped with the coming of GPS. I believe all were VFR and prolly trying to avoid clouds hence the low 1800' altitude or so they were flying at.
S
StewartB
mike mcs repair said:
Marco, the Branch River Air pilot of that accident airplane, is said to have regularly used a SPOT locator as part of his normal day in the cockpit.
There's no reason to believe the 121.5 ELT didn't activate when this accident occurred. There's every reason to believe nobody would have heard it if it did. Advantage 406. In fact this may be the best example I can think of for using 406.
SB
NimpoCub
Registered User
Nimpo Lake, BC . . . AKA "the Floatplane Capital o
A SAR tech @ the last BCFP weekend told me that the 406 first burst is better than GPS, and by the time he gets there he has very accurate info. This chilled my enthusiasm for a GPS equipped 406 (the Pointer). I was surprised to learn that the 121 signal is still what's used to locate you, but it makes sense, a constant signal for their DF thingie.
I also believe in the Spot gizmo (or SpiderTracks) as it gives anyone with your acc't # a good visual of your flight path. If you click on the satellite view, it even shows the terrain, so it's like an aerial video of your flight (albeit with a very slow frame rate).
The PLB would be redundant, and the sat. phone would just confirm you're still breathing.
All good stuff to have w/ya tho unless your flying is just a series of T&G's.
I also believe in the Spot gizmo (or SpiderTracks) as it gives anyone with your acc't # a good visual of your flight path. If you click on the satellite view, it even shows the terrain, so it's like an aerial video of your flight (albeit with a very slow frame rate).
The PLB would be redundant, and the sat. phone would just confirm you're still breathing.
All good stuff to have w/ya tho unless your flying is just a series of T&G's.
fobjob
MEMBER
Salt Lake City, Utah
Look,gang, before anyone gets their panties in a bunch(more coffee!), you have to realize that this is a complex system, and understanding of that complexity is largely lacking...the web sites "explaining" it are crude to the point of idiotic. You have to realize that there are TWO different discussions here:
1. the GPS equipped ELT, and
2. the non-equipped ELT.
The first 406 data burst on a GPS equipped ELT is highly accurate, IF it gets detected.... the location of the non-equipped ELT has to be processed over a period of time before it gets down below several miles; up to several hours, in fact. Even then, it can be off by several dozen miles due to ducting through canyons, and reflections. I went after a 243 ELT on an F16 once, that was "located" by the satellite 35 miles away from where it was parked on the ramp at Hill.
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The Hill tower guy was skeptical, to say the least...." I have a 243 receiver right here,and if there was an ELT signal, I'd hear it." So, utilizing my 35 years(then) of circuit design experience, I said:" Well, give it a good whack."
His next transmission had the blaring tone of an ELT in the background. "So, what do you want to do?" he said.
1. the GPS equipped ELT, and
2. the non-equipped ELT.
The first 406 data burst on a GPS equipped ELT is highly accurate, IF it gets detected.... the location of the non-equipped ELT has to be processed over a period of time before it gets down below several miles; up to several hours, in fact. Even then, it can be off by several dozen miles due to ducting through canyons, and reflections. I went after a 243 ELT on an F16 once, that was "located" by the satellite 35 miles away from where it was parked on the ramp at Hill.
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The Hill tower guy was skeptical, to say the least...." I have a 243 receiver right here,and if there was an ELT signal, I'd hear it." So, utilizing my 35 years(then) of circuit design experience, I said:" Well, give it a good whack."
His next transmission had the blaring tone of an ELT in the background. "So, what do you want to do?" he said.
Thats a good one. I still have an old A/C elt I "found" in Port Townsend years ago. Russian satellite system had reported it and a Coast Guard helicopter DF'd it to town and then called Sheriff's office. It was at a garage sale under a pile of stuff on the ground!. I kept DF'ing on the pile from a 100 or so feet away. Just couldn't make myself believe it was in that pile. When I "found" it the lady said her father had left it at her house years earlier and she figured the batteries were dead. While cleaning her garage her boys had been throwing it around earlier in the day :roll: . I bought it for 5 bucks :lol: and removed the batteries!
mvivion
FOUNDER
Bozeman,MT
mike mcs repair said:
My point regarding the SPOT tracker is that three weeks ago, I launched on a short cross country. I activated the SPOT prior to takeoff. When I returned, I looked at the SPOT track online. There was NO tracking for the first forty miles, then the track started, went to my destination, and started back, with another thirty mile or so gap in coverage. This has happened a NUMBER of times in the two years I've used the SPOT.
That ain't very good coverage, folks. It might help, but the reliability sucks, frankly. As I said, it cant' hurt and it might help....
Stewart,
FYI, the RCC in Alaska informed me that they treat a PLB just like an ELT. So, send me some contact info for someone who knows better. I'd be happy to talk to someone who actually has valid information.
As to the first "hit" on a 406 being precise, that is highly variable, DEPENDING on whether that "hit" gets to BOTH an orbiting satellite AND a geosynchronous satellite. If it gets to BOTH those satellites, the estimated accuracy is FAIRLY good.
Still not nearly as good as a GPS position. If it were, why in the world would EVERY ELT manufacturer be spending many dollars creating GPS enabled ELT equipment????
Call me a liar all you like, Stewart, but do some actual research yourself.
Again, by the time a SAR response even LAUNCHES on a SAR, they will have at least two hits, and position resolution is improved by each additional hit with the 406 system.
Again, Stewart, if your information is so correct, why is virtually every PLB available now equipped with a GPS?? Why is EVERY manufacturer of an aircraft ELT now working on certification (at great cost) of a GPS capability for their ELT?
If your information is accurate, it would seem to me that this would all be a great waste of money on the part of the manufacturers....
MTV
fobjob
MEMBER
Salt Lake City, Utah
On a non- GPS equipped ELT:
1. The 406 Mhz signal (may) reach a geosynchonous satellite, revealing WHO and WHEN, but not WHERE, or it may reach a low earth orbit satellite, revealing only the same info. Then, the doppler location process begins, and the clock starts ticking. Each LEO sat needs several(up to five) 50 second interval, 500 millisecond bursts to get a sample of the doppler shift, then curve matching is done, and a point of maximum doppler shift is interpolated, and that roughly gives latitude, and the amount of interpolated doppler shift gives a rough longitude (distance from the [north-south] sat ground track)estimate, but does NOT resolve if the signal lies left or right of the sat track... it takes at least one more pass to do that. (and the second sat has to be on a different ground track) Then we are down to approximately 20 by 50 miles. It takes more passes (and that can take hours, depending on where the (six) LEO sats are) to get it down to an area that is small enough to dispatch SAR forces. Back in the eighties, AFRCC would NOT notify us until the ground footprint excluded airports.(It took longer when you start with 100 by 200 miles) I don't know if they are still doing that,but I can tell you it pissed us off pretty good.
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The higher a sat is, the less suited it is for doppler location. The 1000 mile GPS sats are getting equipped to monitor and do doppler location, but I don't know if that feature will be very useful. :-?
1. The 406 Mhz signal (may) reach a geosynchonous satellite, revealing WHO and WHEN, but not WHERE, or it may reach a low earth orbit satellite, revealing only the same info. Then, the doppler location process begins, and the clock starts ticking. Each LEO sat needs several(up to five) 50 second interval, 500 millisecond bursts to get a sample of the doppler shift, then curve matching is done, and a point of maximum doppler shift is interpolated, and that roughly gives latitude, and the amount of interpolated doppler shift gives a rough longitude (distance from the [north-south] sat ground track)estimate, but does NOT resolve if the signal lies left or right of the sat track... it takes at least one more pass to do that. (and the second sat has to be on a different ground track) Then we are down to approximately 20 by 50 miles. It takes more passes (and that can take hours, depending on where the (six) LEO sats are) to get it down to an area that is small enough to dispatch SAR forces. Back in the eighties, AFRCC would NOT notify us until the ground footprint excluded airports.(It took longer when you start with 100 by 200 miles) I don't know if they are still doing that,but I can tell you it pissed us off pretty good.
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The higher a sat is, the less suited it is for doppler location. The 1000 mile GPS sats are getting equipped to monitor and do doppler location, but I don't know if that feature will be very useful. :-?
StalledOut
Registered User
Anchorage
If you go to http://searchandrescue.gsfc.nasa.gov/sarsatreports.html and read the reports, the PLB's EPIRBS, ELT's all get reported to the Alaska RCC. What happens next appears to depend on who is in the area and best able to repond. Sometimes it is the Air Guard, sometimes it's local SAR, sometimes it's the Coast Guard. By and large, the PLB's are handled by localized SAR or AST but they are notified via RCC.
Here is an example from 9/29/2010
The COSPAS-SARSAT system detected a 406 MHz PLB distress signal approximately 5 miles southwest of Nuiqsut, Alaska. The operator of a 4 wheeled vehicle activated his PLB when the vehicle experienced engine failure. The Alaska Rescue Coordination Center received the alert and relayed the SARSAT coordinates to the North Slope Borough Search and Rescue Center (NSB). NSB dispatched a rescue team to the coordinates. The rescue team located the operator and transported him back to Nuiqsut, Alaska. No injuries were reported.
Here is an example from 9/29/2010
The COSPAS-SARSAT system detected a 406 MHz PLB distress signal approximately 5 miles southwest of Nuiqsut, Alaska. The operator of a 4 wheeled vehicle activated his PLB when the vehicle experienced engine failure. The Alaska Rescue Coordination Center received the alert and relayed the SARSAT coordinates to the North Slope Borough Search and Rescue Center (NSB). NSB dispatched a rescue team to the coordinates. The rescue team located the operator and transported him back to Nuiqsut, Alaska. No injuries were reported.
mvivion
FOUNDER
Bozeman,MT
And, actually, the first alert message goes to MCC, which is in Suitland, MD, NOT to RCC, of which there are two for land searches: One in Anchorage and one at Tyndall AFB in FL. The signal is verified by MCC, and the contact information is accessed THERE, then if it appears a search is justified, the information is passed on to the appropriate RCC.
There are also RCC's for marine, as well, so all the signals go through MCC FIRST, are verified, and passed along to the appropriate RCC, based on the registry of the beacon.
Take a look at http://www.sarsat.noaa.gov/
And, click on MCC first, then RCC on the left series of links.
Lots of information here.
Again, if the FIRST 406 hit were even close to as precise as Stewart suggests, why would every GPS manufacturer be scrambling to certificate a GPS enabled ELT?
MTV
There are also RCC's for marine, as well, so all the signals go through MCC FIRST, are verified, and passed along to the appropriate RCC, based on the registry of the beacon.
Take a look at http://www.sarsat.noaa.gov/
And, click on MCC first, then RCC on the left series of links.
Lots of information here.
Again, if the FIRST 406 hit were even close to as precise as Stewart suggests, why would every GPS manufacturer be scrambling to certificate a GPS enabled ELT?
MTV
S
StewartB
Mike,
I understand the truth doesn't matter to you as much as you portraying yourself as right. Frankly, I don't care what you think of me. I care that the guys that read your comments stop and consider what you've said. Mit Greb said the switch to 406 wasn't handled well. It was handled brilliantly in my opinion. The public was offered information to educate themselves and then provided ample time to adopt the new transmitters. When the anticipated deadline came and passed that made 121.5 completely obsolete, many ignored the obvious and failed to change. Many like you, and for whatever reason you seem to have an agenda to persuade others to continue to fly with outdated and useless ELTs in their planes. It has long been said the pen is more powerful than the sword. Yours is an example of the negative side of that argument. Why intelligent men accept your opinions as important defies all logic. Some accept your half baked research and misguided assumption as the whole truth. You have done them a great disservice.
Manufacturers are not particularly interested in your safety. They are interested in gross revenues and profit margins. But you're not a private industry guy so that concept isn't engrained in you, right? Your buddy at Artex is charged with making a product that complies with strict specifications that he has zero control of. How does the system work? Why would he care? As long as his yellow box deploys per spec and transmits per spec and he can make the company an extra nickel or two he's done his job. Pure and simple. Nothing wrong with that, either. I'm a fan. I'm a customer. I bought two of his boxes. On the other hand, talk to the SAR guys. They take your safety personally. They'd rather pick up a living person than a dead body. Those are the guys on the front line and the ones who understand what does and does not work. Do some intelligent research. Break out that pen and tell these guys the truth. It isn't about your initial statements being right. It's about doing the right thing.
I'm done with this conversation, these attitudes, and this website. At least for a while. Fly safely. Whether I like or respect you has no bearing on the fact that I hope you don't die unnecessarily in a time when technology can help prevent it.
That 406 location capability exceeds design expectations is a gift to all of us. That we in Alaska have such fantastic rescue assets standing by to assist us is a blessing. I choose to empower the latter by utilizing the former.
Over and out.
Stewart
I understand the truth doesn't matter to you as much as you portraying yourself as right. Frankly, I don't care what you think of me. I care that the guys that read your comments stop and consider what you've said. Mit Greb said the switch to 406 wasn't handled well. It was handled brilliantly in my opinion. The public was offered information to educate themselves and then provided ample time to adopt the new transmitters. When the anticipated deadline came and passed that made 121.5 completely obsolete, many ignored the obvious and failed to change. Many like you, and for whatever reason you seem to have an agenda to persuade others to continue to fly with outdated and useless ELTs in their planes. It has long been said the pen is more powerful than the sword. Yours is an example of the negative side of that argument. Why intelligent men accept your opinions as important defies all logic. Some accept your half baked research and misguided assumption as the whole truth. You have done them a great disservice.
Manufacturers are not particularly interested in your safety. They are interested in gross revenues and profit margins. But you're not a private industry guy so that concept isn't engrained in you, right? Your buddy at Artex is charged with making a product that complies with strict specifications that he has zero control of. How does the system work? Why would he care? As long as his yellow box deploys per spec and transmits per spec and he can make the company an extra nickel or two he's done his job. Pure and simple. Nothing wrong with that, either. I'm a fan. I'm a customer. I bought two of his boxes. On the other hand, talk to the SAR guys. They take your safety personally. They'd rather pick up a living person than a dead body. Those are the guys on the front line and the ones who understand what does and does not work. Do some intelligent research. Break out that pen and tell these guys the truth. It isn't about your initial statements being right. It's about doing the right thing.
I'm done with this conversation, these attitudes, and this website. At least for a while. Fly safely. Whether I like or respect you has no bearing on the fact that I hope you don't die unnecessarily in a time when technology can help prevent it.
That 406 location capability exceeds design expectations is a gift to all of us. That we in Alaska have such fantastic rescue assets standing by to assist us is a blessing. I choose to empower the latter by utilizing the former.
Over and out.
Stewart
S
StewartB
Fobjob, An airline that reports a 121.5 beacon from 35,000 feet has identified a beacon going off somewhere in a region about the size of Texas. Without localization nobody's coming. MTV can research that with RCC, too. It's true.
Stewart
Stewart
fobjob
MEMBER
Salt Lake City, Utah
However, we used to get reports like that, and we would launch a 182 to overfly the area at high altitude to get a location, even at night. The feds wouldn't fund it, but the state of Utah would. If there were airports in the area, we would usually alert the local guys to check out the airports.
So, I am assuming that the 121.5 ELT's still have value....
So, I am assuming that the 121.5 ELT's still have value....
mvivion
FOUNDER
Bozeman,MT
Stewart,
Interesting response. And, once again, it is obvious that you did not read my most recent comments on this thread.
A few pages back, I noted that, after talking to the folks who design and manufacture the ELT's, I have actually decided that I WILL upgrade to a 406 beacon. BUT, I'm not going to do that until the technology is slightly more refined. I believe we are close to that point, but I'll buy one when one is available WITH GPS connectivity, and not before.
I don't just talk to neighbors about this stuff, I try to do a little actual research on the subject. To that end, perhaps a review is in order:
1) There is no question the 406 beacons offer SOMEWHAT BETTER initial location accuracy than a 121.5 beacon does, and MUCH better location data after a few more satellite passes. And, MCC does not wait for several more hits before they initiate an alert notification, assuming they are unable to contact the owner of the beacon. That means MUCH less time between activation and a response being initiated. And, that is all good. A "one hit" 406 activation, however, still provides pretty general location data, and will NOT result in a precise set of coordinates of the crash site. Hence, if I'm going to spend the money for a "new and improved" ELT, I want one with GPS connectivity. That first burst will then provide precise location data, at least within the capabilities of the GPS.
2) The newest versions of ELTs are still using precisely the SAME activation switches as the old 121.5 devices used, and the reliability of activation of those switches is not that great, historically. So, is an ELT THAT much better than a PLB? I dunno, but I'd sure like to see a MUCH more reliable G-switch in the "latest and greatest" ELTs. The technology is there to provide such a device, but FAA certification is the hold up, as usual. Doesn't sound like that's going to happen soon. In the meantime, I now know that repetitive maintenance and testing of the ELT is essential to improve the odds of that primitive G-switch activating, and I intend to see that this is done on my unit.
3) It turns out, according to one of the manufacturer's reps, that in 40 % of the cases where a crash occurred and the ELT did not activate, the ELT broke free of its mounting and was separated from it's antenna. The ELT, in some of these cases, actually DID activate via the switch, but it was no longer connected to its antenna. This was the case in the tragic accident involving the GCI Otter this summer in Alaska. When my new 406 beacon is installed, I'm going to consult with my mechanic on how best to ensure that the thing is solidly mounted in the airframe, and it's going to be secured as tight as is possible.
During the course of this online discussion, I have somewhat changed my mind on 406 beacons. I have certainly learned a lot about the system and equipment. That is WHY one does research, and asks questions of REAL experts who fully understand how the system works--to inform oneself better.
Obviously, you are unwilling to share your sources of information, even though you offered to do so, and I asked for that information.
I invite folks to contact Scott Roth at Cobham Avionics if they have questions regarding how these systems actually work. I'm betting that the guys who design the equipment have a fairly good grasp of how the system actually works. And, take a good, thorough look at the NOAA site for more information on the system as well.
But, of course, I'm just making this stuff up so that I look good....
MTV
Interesting response. And, once again, it is obvious that you did not read my most recent comments on this thread.
A few pages back, I noted that, after talking to the folks who design and manufacture the ELT's, I have actually decided that I WILL upgrade to a 406 beacon. BUT, I'm not going to do that until the technology is slightly more refined. I believe we are close to that point, but I'll buy one when one is available WITH GPS connectivity, and not before.
I don't just talk to neighbors about this stuff, I try to do a little actual research on the subject. To that end, perhaps a review is in order:
1) There is no question the 406 beacons offer SOMEWHAT BETTER initial location accuracy than a 121.5 beacon does, and MUCH better location data after a few more satellite passes. And, MCC does not wait for several more hits before they initiate an alert notification, assuming they are unable to contact the owner of the beacon. That means MUCH less time between activation and a response being initiated. And, that is all good. A "one hit" 406 activation, however, still provides pretty general location data, and will NOT result in a precise set of coordinates of the crash site. Hence, if I'm going to spend the money for a "new and improved" ELT, I want one with GPS connectivity. That first burst will then provide precise location data, at least within the capabilities of the GPS.
2) The newest versions of ELTs are still using precisely the SAME activation switches as the old 121.5 devices used, and the reliability of activation of those switches is not that great, historically. So, is an ELT THAT much better than a PLB? I dunno, but I'd sure like to see a MUCH more reliable G-switch in the "latest and greatest" ELTs. The technology is there to provide such a device, but FAA certification is the hold up, as usual. Doesn't sound like that's going to happen soon. In the meantime, I now know that repetitive maintenance and testing of the ELT is essential to improve the odds of that primitive G-switch activating, and I intend to see that this is done on my unit.
3) It turns out, according to one of the manufacturer's reps, that in 40 % of the cases where a crash occurred and the ELT did not activate, the ELT broke free of its mounting and was separated from it's antenna. The ELT, in some of these cases, actually DID activate via the switch, but it was no longer connected to its antenna. This was the case in the tragic accident involving the GCI Otter this summer in Alaska. When my new 406 beacon is installed, I'm going to consult with my mechanic on how best to ensure that the thing is solidly mounted in the airframe, and it's going to be secured as tight as is possible.
During the course of this online discussion, I have somewhat changed my mind on 406 beacons. I have certainly learned a lot about the system and equipment. That is WHY one does research, and asks questions of REAL experts who fully understand how the system works--to inform oneself better.
Obviously, you are unwilling to share your sources of information, even though you offered to do so, and I asked for that information.
I invite folks to contact Scott Roth at Cobham Avionics if they have questions regarding how these systems actually work. I'm betting that the guys who design the equipment have a fairly good grasp of how the system actually works. And, take a good, thorough look at the NOAA site for more information on the system as well.
But, of course, I'm just making this stuff up so that I look good....
MTV
StalledOut
Registered User
Anchorage
Stewart wrote "That 406 location capability exceeds design expectations is a gift to all of us"
406Mhz is a frequency, plain and simple. It does not have any magic location capability.
The newer 406MHz based transmitters however do accept input from external GPS's or have built in GPS.
When activated they will send the lat/long out if they have it and if they are setup properly. That's not a given.
A 406Mhz ELT without GPS information will require several passes to gain any kind of accurate location information. That's not a quick process and can take several hours.
To add another variable in, there are two message formats for 406MHz transmissions. Long and Short. Short is limited to 112 bits and has no position data. Long is limited to 144 bits and does contain position data.
It is possible to have a GPS enabled 406MHz ELT and have it set to only transmit short messages. It all depends on the programming.
406Mhz is a frequency, plain and simple. It does not have any magic location capability.
The newer 406MHz based transmitters however do accept input from external GPS's or have built in GPS.
When activated they will send the lat/long out if they have it and if they are setup properly. That's not a given.
A 406Mhz ELT without GPS information will require several passes to gain any kind of accurate location information. That's not a quick process and can take several hours.
To add another variable in, there are two message formats for 406MHz transmissions. Long and Short. Short is limited to 112 bits and has no position data. Long is limited to 144 bits and does contain position data.
It is possible to have a GPS enabled 406MHz ELT and have it set to only transmit short messages. It all depends on the programming.
