121.5/246 ELTs vx 406 mHz

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121.5/246 ELTs vx 406 mHz

Postby GAHorn » Wed Nov 24, 2021 4:02 pm

I have received at least a half-dozen calls recently from Members who inquire about “which 406 mHz ELT” I have in my airplane. The caller is often surprised to find I don’t have one. I am still nursing my 121.5/246 mHz ELTs.

When I bought the 172 two years ago (our son wanted to learn to fly and foolishly thought I’d use the 170 for his crash-and-go practice)… it had an old ACK unit whose mfr’r has been run out-of-business by the FCC/FAA …(they are prohibited from working on ANY ELT including their own) …and no parts are available…. I unfortunately discovered it had been installed incorrectly and not in conformity with it’s original instructions. It had no Cockpit Remote. Further, it’s antenna was broken.
To my rescue comes another 170 Assoc’n Member…. Wendell Wyborny…who not only had a NOS antenna…. he had a Cockpit Remote which had been removed when he “upgraded” his ELT to something more modern…. so we were able to bring the old ACK 121.5/246 unit into compliance.
Being a member of “CHAOS”….(no, not the imaginary cold-war opponent in the ‘70s TV show “Get Smart”)…. I belong to the Cheap Handy Aircraft Owners Society

Paul Bertorelli and I think along similar lines….and Aviation Consumer (to which I subscribe) had a recent article on them which pretty well convinces me that ALL ELTs are of questionable value and 406 ELTs are not much better than the original Sad Idea. Hale Boggs is still unfound and even if he had an ELT he’d have 98% chance of still being missing.

https://www.youtube.com/watch?v=d1YjGLwfYSQ
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Re: 121.5/246 ELTs vx 406 mHz

Postby mit » Wed Nov 24, 2021 10:28 pm

I agree with you on this George.
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Re: 121.5/246 ELTs vx 406 mHz

Postby c170b53 » Thu Nov 25, 2021 12:36 am

If there’s any chance, I’ll take it.
My 406 works every time I test it and I get a email response from the Sat folks the next day that the Sat picked me up. No guarantee and an added expense but I can live with that.
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Re: 121.5/246 ELTs vx 406 mHz

Postby ghostflyer » Thu Nov 25, 2021 3:13 am

I was under the impression that the 121.5/246 freq is now not monitored . Plus a lot of the 406 ELTS have the gps position system. I have done a check on my 406 ELT in some remote areas to ease my concerns and found the test satisfactory .
A friend of mine went camping with his “girl friend” in his Cessna 150. He kept his 406 ELT in the seat pocket behind him. About 2am in the morning came this wok,wok,wok, sound and then his tent was blown to bits . It was a large Bell 412 helicopter it was was search and rescue . They landed and asked if they were in trouble . No?? , well your ELT has been activated for the last 4 hours . Inspection of the Cessna 150 found the ELT s/w had been activated. It appeared the “girlfriend” had her arm around him [and the seat] and had activated the ELT. Overhead was a airline traffic lane and it was activating their radios. Both parties had switched off their cell phones for the trip away. .there is more to the story than this but we have to keep the juicy bits out .
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Re: 121.5/246 ELTs vx 406 mHz

Postby GAHorn » Thu Nov 25, 2021 6:54 am

LOLOL…. the best laid plans o’ mice and men….
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Re: 121.5/246 ELTs vx 406 mHz

Postby IA DPE » Thu Nov 25, 2021 3:08 pm

I'm with Jim.

While I don't fly in remote areas, if the ELT saves time in an injury accident, to me, it's worth the cost. When I installed my new IFR avionics the shop said it was possible to have the GPS send position info to the ELT, for additional installation cost of course. I paid the money. Hopefully it was a waste.
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Re: 121.5/246 ELTs vx 406 mHz

Postby Bruce Fenstermacher » Thu Nov 25, 2021 6:49 pm

I'm a cheap bastard pilot like Paul. Even have the same ELT. But I do have a better method of disassembling the old battery pack called a band saw. :D
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Re: 121.5/246 ELTs vx 406 mHz

Postby GAHorn » Thu Nov 25, 2021 11:07 pm

Bruce Fenstermacher wrote:I'm a cheap bastard pilot like Paul. Even have the same ELT. But I do have a better method of disassembling the old battery pack called a band saw. :D


Bruce… The company that produced that particular ELT has a particulalry bitter attitude about insisting that only their proprietary batteries be used with their ELTs I’m told…I’m thinking the “owner produced parts” rule should apply to ELT batteries also…. Whadda you think>..??
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Re: 121.5/246 ELTs vx 406 mHz

Postby Bruce Fenstermacher » Fri Nov 26, 2021 1:36 am

GAHorn wrote:Bruce… The company that produced that particular ELT has a particulalry bitter attitude about insisting that only their proprietary batteries be used with their ELTs I’m told…I’m thinking the “owner produced parts” rule should apply to ELT batteries also…. Whadda you think>..??


Without investigation of all the legalities, I'm thinking the ELT that meets the FAR would be made to a TSO. And that TSO would have to be maintained. I'd think the battery would be part of the TSO. Could an owner produced part meet the standard? I'd bet you wouldn't get the same answer from any 2 Feds.

I have no doubt I could make a battery equally as safe and reliable as the store bought one. But it may cause nearly what you pay for one.

While the batteries are available, I'll just buy them. When they are not, I may see how my IA feels about an owner produced battery.
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Re: 121.5/246 ELTs vx 406 mHz

Postby GAHorn » Fri Nov 26, 2021 2:23 am

I was just thinking that if the EBC battery is just a plastic case with AA Durcells in it that an Owner pack using the same batteries would meet the rule for Owner produced part…. and I don’t know for sure…but I don’t believe a TSO prevents an OPP…. because by prescription it is identical.
Ordinarily I’m really picky about things…but if I had an EBC I’d have no compunctions against installing new duracells in it by digging-out the old batts and installing new. Even if you had to replace the holder…

The EBC costs $42. The duracells are about $8 and the battery holder about $2. Admittedly It’s not just about cost tho’.
$1.95 buys this:
E3E93DD5-AA47-43BC-AC1E-381FE569D48F.jpeg
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Re: 121.5/246 ELTs vx 406 mHz

Postby TFA170 » Fri Nov 26, 2021 4:10 am

ghostflyer wrote:I was under the impression that the 121.5/246 freq is now not monitored . Plus a lot of the 406 ELTS have the gps position system. I have done a check on my 406 ELT in some remote areas to ease my concerns and found the test satisfactory .

The military still monitors 243.0 - every military UHF radio has a "both" position where it monitors 243.0 and the designated frequency/channel - most military regulations require "both" to be selected unless there is undue interference. Similarly, on dual VHF equipped aircraft, monitoring of 121.5 is encouraged.

All the military SAR assets still have 121.5/243.0 ability.

The 406 does indeed have the GPS location ability via data burst.
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Re: 121.5/246 ELTs vx 406 mHz

Postby Bruce Fenstermacher » Fri Nov 26, 2021 1:23 pm

GAHorn wrote:I was just thinking .....


Having changed out a few of the EBC batteries, I know it is a tight fit. First the pack George pictured is an 8 cell pack and the EBC uses 6 cells. There may be such a battery holder available. But I'd bet the holder wouldn't fit inside the ELT. Second without reading and understanding TSO C91A I'd wonder if an open spring loaded case would meet the TSO. Yes there are one or two other ELTs with replaceable store bought cells so maybe.

IF it ever comes down to an OPP battery for an EBC I'd attempt to tackle it by soldering the cells together, aligned and tight. I'd then explore a thin shrink wrap or incase them in epoxy resin similar to MERL. Could I mess with this and do it for half the cost not counting my time. Yes, and it is tempting. At least the challenge to do it and getting my IA on board is. Gee as many of these, "I can do it at half cost" ideas I get involved in, I wonder how I end up spending twice as much. 8O
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Re: 121.5/246 ELTs vx 406 mHz

Postby GAHorn » Fri Nov 26, 2021 2:40 pm

I believe it’s the 121.5/246 mHz freqs that are no longer monitored by satellite…. ATC facilities still monitor it, as does most commercial/airline/military operators on 2nd comms.

Procrastination….and Monitoring 121.5 mHz probably kept me from becoming nationally infamous…. and unemployed.

I have a single Narco 810 com in my 170 and it was installed without activating the “keep alive” circuit for it’s memory….I.E. if a hot battery lead is added it will recall what freq it was on when last shut-down…. Otherwise it always “wakes up” on 121.5 mHz. I toyed with the idea of adding the keep-alive feature to it…. but had procrastinated it because I didn’t relish removing my recently-illuminated instrument panel cover. Then, one early morning I was saved from my own idiocy by it’s 121.5-wake-up feature.

Jamie and I were headed out from our private ranch-strip around 8AM to make a fly-in hosted by our recently Gone West friend Frank Stephenson at the Ft Worth Spinks airport. I was enjoying one of those early-morning smoooth cruise-climbs gliding up over the central Texas “hill country” and Jamie settled down to reading one of her books. I had been recently promoted at work from ordinary I. P. (simulator Instructor-Pilot) to T.C.E. (Training Center Evaluator which is analogous to a Designated Pilot Examiner) and was feeling pretty smug about myself…. when a transmission by “Gray Approach” (Ft. Hood Army Airfield Traffic Control) was broadcast in the “blind” to …. “Aircraft Southwest of Killeen. be advised of Restricted Area 6302C is temporarily enlarged, Contact Gray Approach on 120.75.”.

I thought to myself “Some doofus is about to get into trouble”…. It was only a few months after airspace had opened up after Nine-Eleven and Pres. Bush had recently been assigned a Prohibited Area over his Crawford Ranch nearer Waco. Being a “local”….I was intimately familiar with this area, of course….no problem for ME… :roll:

A few minutes later a more-urgent tone was again issued to the “aircraft 25 southeast of Gooch Springs VOR indicating 3500’ are you on freq.? Turn West Immediately”.

I thought “Yep…some fool is gonna see a Blackhawk up close-and-unfriendly if he doesn’t wake up!”. Then I thought “Gooch Springs”…?? Where the Hell is that…??

The Lampasas VOR was my reference point on this flight and …. “OH!… YEah… they’ve recently re-named that thing haven’t they”
“What did you say?”, Jamie asked…. I hadn’t realized I had actually vocalized my thoughts interupting her reading…. so I explained to her. “Some idiot is about to get intercepted because he’s about to enter a “hot” restricted area!”
“Oh”, she acknowleged, returning to her book.

About that time the controllers voice became quite adamant - - - “Aircraft Northbound 15 SouthWest of Gray AAF at 3500-feet Turn West IMMEDIATELY to avoid Restricted Airspace!”…
It was his much-excited voice that caused me to realize I was “northbound”…. I was Southwest of Gray (Hood) and I was at 3500’…. I had been unconcerned about flying thru a plain-Jane MOA…. I had not checked NOTAMS before this early AM Saturday no-flight-plane pleasure-flight…. basically having violated everything I preached to others at work….. AND IT WAS ME WHO WAS THE DOOFUS ABOUT TO BE INTERCEPTED! ….(the MOA-turned-R-6302 had become sensitive airspace as the result of Nine-Eleven… The airspace change wasn’t depicted on my Garmin or on current charts.)

I instantly jerked the airplane into a Due-West heading ….and avoided the MOA (by less than a mile) which had been NOTAM’d just that morning to be re-assigned as a RESTRICTED AREA instead….. and it was the little Narco 810 that wakes-up on 121.5 …the only thing that would finally break-thru the brain-fog complacency I’d fallen into….

So… recovering from the adrenalin rush …. I then switched-over to 120.75 and called up Gray Approach…. and in my best imitation of a casual Chuck Yeager asked them if they could arrange “flight following”… was assigned a beacon-code and continued to the Fly In at Babe’s Fried Chicken in Ft Worth….. and I realized that only one more mile mindlessly flying along likely would have resulted in an “intercept” and national headlines. The newly-authorized pilot “evaluator” at the nationally-known simulator facility doubtlessly would have been fired when they realized it was their newest idiot in the national headlines.

Stoopid IS as Stoopid DOES….. and this is why I’m admitting all this to my friends…. I hope everyone will add 121.5 to their “listening watch” …even if only “mindlessly flying-around”. … and perhaps we can all continue to avoid being in the National News.

It’s embarrassing to admit publicly that I’d done this…. :oops: ….but I hope it helps us all.
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Re: 121.5/246 ELTs vx 406 mHz

Postby TFA170 » Sat Nov 27, 2021 12:46 am

Correct - SARSAT/COSPAS no longer monitors 121.5/243.0 or HF - only 406

Not that it matters for our GA aircraft, but the UHF guard frequency is 243.0 (not 246 - easy to remember: double 121.5)
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Re: 121.5/246 ELTs vx 406 mHz

Postby GAHorn » Sat Nov 27, 2021 3:21 am

TFA170 wrote:Correct - SARSAT/COSPAS no longer monitors 121.5/243.0 or HF - only 406

Not that it matters for our GA aircraft, but the UHF guard frequency is 243.0 (not 246 - easy to remember: double 121.5)


I knew that. I’m just bad at math. :lol:
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