Ok I?ve done google searches and forum searches on the legality and it looks like the ruling is that it?s still legal to maintain and use an old 121.5 ELT. My question aside from the safety aspect, which I?m well aware of, is it legal to install an old 121.5 MHz in a new project? I plan on upgrading within a year or so of test flying but want to just be legal to get the plane in the air. Any input on the legal aspect of using one of these older units please. Thanks.
Van's Air Force
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121.5 MHz ELTs
- Thread starter Maxrate
- Start date
I just went through this with my 170 when my old ELT didn't pass inspection. Here are MY thoughts. The old emergency frequencies 121.5/243.0 are no longer monitored except by other aircraft. If your ELT is activated, IF someone hears it, IF someone can locate you, it could be hours...or longer.
With the 406 ELT, if activated the signal can be located in minutes. The receiver knows the aircraft ID, Type, home base and pilots phone numbers. If your ELT gets a GPS signal, the time to locate could be seconds.
That's how I understand it and why I went with a 406 ELT.
With the 406 ELT, if activated the signal can be located in minutes. The receiver knows the aircraft ID, Type, home base and pilots phone numbers. If your ELT gets a GPS signal, the time to locate could be seconds.
That's how I understand it and why I went with a 406 ELT.
There are still way too many accidents where the 406 doesn't activate, or activates with a broken antenna and the signal doesn't get out anyway. There is better technology available that provides equivalent locating service with added benefits (live tracking, two-way messaging, etc.). It's high time they were allowed as alternatives.
Sam Buchanan
been here awhile
Also interested in the answer to the original question.
121.5 has to still be monitored as it is still the international designated frequency to declare a Mayday. If no longer monitored on the ground, what is the new frequency to call a Mayday?
121.5 is monitored on the ground, but no longer by satellite. 121.5 being line of sight has a very short range ground to ground. CAP can DF 121.5 but they only do so if they know to go looking.
IMO, a 121.5 ELT, while legal, even for new installations, is almost dead weight.
91.207 is the applicable Reg for requirement.
IMO, a 121.5 ELT, while legal, even for new installations, is almost dead weight.
91.207 is the applicable Reg for requirement.
If you are that intent on saving a buck, why don't you remove the extra seat; then you don't need ANY ELT as per 14 CFR 91.207(f)(9)
Or you could just bite the bullet, spend the $.5AMU and get the ACK ELT-04. It won't hurt -- I promise...
Cheers...
N941WR
Legacy Member
I couldn't agree more!
Radioflyer
Well Known Member
I'm thinking that a good approach is to have the old 121.5 elt for legality reasons plus an Inreach PLB for 406mHz coverage as effective as an aviation specific unit. You have to pay a subscription, And you have to manually arm the thing, but the portability has its advantages as well.
ELT
No aircraft system is perfect but I've spent many search hours through the years looking for missing planes back when ELT's were not required or just not installed, or evidently failed, and there are still missing planes in the North West US that have never been found. But on searches where the ELT worked as advertised planes were found and lives were saved. A 406 beacon is so much better it's like night and day for rescue services, and in many situations the hours saved mean lives saved. But no body ever thinks it will be them.
There is no subscription cost for a 406MHZ PLB ELT, you just register it the same as the aircraft 406 MHZ ELT's. But it has to be manually activated. It's the Garmin Spot type tracker beacons that have to have a subscription. But they are not a substitute for the FAA 406 ELT and are not monitored by any rescue services. All 406 MHZ beacons are monitored and will generate a response if activated. I have an ACK 406 aircraft beacon in my plane and a 406PLB in my raft and survival kit.
The 121.5 MHz simulcast transmission from the 406 Beacons are for close in DF purposes only and I believe have less power out than the old 121.5/243 ELT's. The 406 beacon is actually a short data burst transmission that just sends a beacon ID that is relayed by satellite to a ground station and is used to look up your aircraft and owner information at the rescue coordination center and will also send a precise Lat/Long location if the owner has provided that data to their ELT. The 406 frequency is more precise than the the old 121.5 beacons and by using multiple satellite passes and ground station processing they can get a much better processed ELT location (when no Lat/long location is provided in the beacon data) than the old beacons.
There is at least one old 121.6/243 ELT beacon that the FAA says if if breaks it can't be repaired and must be replaced ( can't remember the type) due to some major defect.
ADSB (978 MHz) does provide some measure of additional emergency support since if your equipped every movement of your plane is tracked and recorded by the FAA computers ground networks ( when within line of sight of a ground station). Plus the 1090 Mode S transponders are now tracked by satellite on the new Iridum system. This is why Canada is pushing Mode S ADSB with dual transponder antennas (top and bottom) even though the satellites have had pretty good luck tracking bottom located transponder antennas). But to generate a rescue response you would have to select 7700 on your transponder.
Just some food for thought.
No aircraft system is perfect but I've spent many search hours through the years looking for missing planes back when ELT's were not required or just not installed, or evidently failed, and there are still missing planes in the North West US that have never been found. But on searches where the ELT worked as advertised planes were found and lives were saved. A 406 beacon is so much better it's like night and day for rescue services, and in many situations the hours saved mean lives saved. But no body ever thinks it will be them.
There is no subscription cost for a 406MHZ PLB ELT, you just register it the same as the aircraft 406 MHZ ELT's. But it has to be manually activated. It's the Garmin Spot type tracker beacons that have to have a subscription. But they are not a substitute for the FAA 406 ELT and are not monitored by any rescue services. All 406 MHZ beacons are monitored and will generate a response if activated. I have an ACK 406 aircraft beacon in my plane and a 406PLB in my raft and survival kit.
The 121.5 MHz simulcast transmission from the 406 Beacons are for close in DF purposes only and I believe have less power out than the old 121.5/243 ELT's. The 406 beacon is actually a short data burst transmission that just sends a beacon ID that is relayed by satellite to a ground station and is used to look up your aircraft and owner information at the rescue coordination center and will also send a precise Lat/Long location if the owner has provided that data to their ELT. The 406 frequency is more precise than the the old 121.5 beacons and by using multiple satellite passes and ground station processing they can get a much better processed ELT location (when no Lat/long location is provided in the beacon data) than the old beacons.
There is at least one old 121.6/243 ELT beacon that the FAA says if if breaks it can't be repaired and must be replaced ( can't remember the type) due to some major defect.
ADSB (978 MHz) does provide some measure of additional emergency support since if your equipped every movement of your plane is tracked and recorded by the FAA computers ground networks ( when within line of sight of a ground station). Plus the 1090 Mode S transponders are now tracked by satellite on the new Iridum system. This is why Canada is pushing Mode S ADSB with dual transponder antennas (top and bottom) even though the satellites have had pretty good luck tracking bottom located transponder antennas). But to generate a rescue response you would have to select 7700 on your transponder.
Just some food for thought.
gmcjetpilot
Well Known Member
It is a waste of time to install a 121.5/243 ELT. Why bother. You can get a good 406 ELT fairly inexpensively. It is far far more accurate and more likely to save your bacon. The new ELT's have better batteries. The old ELT designs go back to the 1970's.
ADS-B is NOT a substitute for ELT by any stretch. That is just not correct.
121.5 is for local homing and has limited range. It is not monitored by satellites. All 406 ELT's have 121.5 as well. No new ELT's have 243.
243 is monitored by military satellites as a courtesy, but coverage has huge gaps in geography or frequency of time passing overhead. Then the time to report to local authorities, lack accuracy, means no one will know who you are, where you are for a long time, if ever. For all intents and purposes 243 is not monitored.
406 for gosh sakes, I am cheap but this seems like a no brainier. If you pipe in GPS position into the 406 ELT you are far more likely to get help fast. The constellation of new 406 satellites makes the choice of what should be in your plane obvious. At some point 406 will become mandatory.
121.5/243 Legal? OK. Personally I have a yellow EBC I use for a paper weight. What's the next question, can I install a King KX170B and NDB remove my GPS? Yes you can, but somethings need to be retired (including me, soon I hope).
ADS-B is NOT a substitute for ELT by any stretch. That is just not correct.
121.5 is for local homing and has limited range. It is not monitored by satellites. All 406 ELT's have 121.5 as well. No new ELT's have 243.
243 is monitored by military satellites as a courtesy, but coverage has huge gaps in geography or frequency of time passing overhead. Then the time to report to local authorities, lack accuracy, means no one will know who you are, where you are for a long time, if ever. For all intents and purposes 243 is not monitored.
406 for gosh sakes, I am cheap but this seems like a no brainier. If you pipe in GPS position into the 406 ELT you are far more likely to get help fast. The constellation of new 406 satellites makes the choice of what should be in your plane obvious. At some point 406 will become mandatory.
121.5/243 Legal? OK. Personally I have a yellow EBC I use for a paper weight. What's the next question, can I install a King KX170B and NDB remove my GPS? Yes you can, but somethings need to be retired (including me, soon I hope).
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Everything in aviation can be done "fairly inexpensively", some things more than others and some people care about the cost/benefit. Batteries were rarely a cause of failed ELT's, and in the case where they were, it was a user who never replaced them... Likely still to happen with a 406. And the technology used in the 406 is no different than that used in the 121.5 ELT's... They're both transmitting a signal for someone to listen for. The content of the signal has changed, but that's it. It's still 40 year old technology.
All it needs is an impact switch or a manual emergency button to trigger it.
IF you have a 406 that takes a GPS signal, and you activate it before you crash so the 406 has time to read the GPS location and send a signal before you crash and rip off the antenna. Or IF you have a 406 with its own GPS AND the antennas survive the crash.
I think technology is changing so fast in this space that it's more likely that whatever replaces 406 will be mandated before they get around to mandating 406. There's a lot of demand for live tracking after the Malaysian Airlines disappearance, and the Aireon system (space-based ADS-B) does provide it. All it needs is an alerting function (maybe squawking 7700 is it, for now, but an "emergency" button on the panel would do it as well).
Couldn't get it to activate no matter what you did to it.
Yes, was a bit confused by the apparent contradiction myself. Reread the far's, Fed Register.
Bottom line: The earlier 121.5 TOC91 is no new install. Later TSO C91A 121.5 unit is OK to install as well as the TSO C126B 406mhz unit.
n82rb
Well Known Member
Wanted to add that as the op did not say how old it was.
