ELT on Expermentals

[Danzer1]

You are way off on how radio transmitters work. All military aircraft are still required to monitor 121.5 and your theory on the 40K thing for airliners is false. If that were the case, satellites would never have been able to monitor 121.5. I don't disagree that 406mhz transmitters are the way to go, but please don't spread trash on a subject you have little knowledge about.

Really? All 121.5 elt's transmit at between 75 and 100 milliwatts. All 406's transmit at 5 watts - 50 times the power and a hell of a lot more range. Most consider 100 milliwatts to be good for voice clarity at a 1/4 mile at the most. Aircraft at 30-40k feet would have to discern the (weak) tone from other background noise and clutter, and that has been determined to be difficult at best at that altitude. The satellites receivers were designed to pick out the (weak) tone and send it's location back to a ground station. There was over a 90% failure rate (false alarms) due primarily to not being able to discern an emergency tone from clutter/other noise - the main reason they stopped bothering to monitor it!

One of the problems with 121.5's was the satellite had to be very near overhead (and line of sight) to pick up a signal and then forward it to a ground station, hence coverage of only 60% of the earth at any one time and also why it could take up to 6 hours for a signal verification.

121.5 and 243.0 are still "guard" channels and are primarily monitored for VOICE emergency communications (usually transmitted at 5 watts or higher) - not elt's at 100 milliwatts or lower. Ask any SAR agency if they will deploy based on any single 121.5 signal tone. Also ask anyone the effective range (discerned identification of signal or voice) of a 100 milliwatt transmission. Go ahead ask and then get back to us without the snide commentary please.

[Danzer1]

John,

Someone correct me if I'm wrong, but I believe I read that you must use a 406 unit on a new installation. If your aircraft was previously legally airworthy with 121.5, then you can still replace it with a new 121.5 unit, for now. This is in the USA of course.
Also, if your aircraft is a single place machine, you don't need an ELT. That's how it used to be anyway.

Kind of, sort of, but not quite: The FCC's 3rd attempt at an NPRM is in the works and could be made a rule at any time - comments closed last March. If and when passed, it calls for

1, The FCC to stop certifying new 121.5 ELT's immediately (the FAA has already stopped, so that's a mute point).

2, The cease of import of 121.5 ELT's immediately.

3, The stop of sale of all 121.5 ELT's a year after passage of the rule.

4, The transition to a 406 ELT within 8 years of passage of the rule.

So (if and when passed) you'd have a hard time getting a 121.5 and you'd have to have a 406 anyway in no more than 8 years.

No mention if the current NPRM version still exempts single seat aircraft (as is current).

[Peteohms]

"The most common exceptions to the ELT requirements are for aircraft used in training within a 50-mile radius of their base of operations, aircraft used in aerial application (crop-dusters) and aircraft undergoing certification testing. Additionally, an exception is made for operation of an aircraft while the ELT..."

Read more : http://www.ehow.com/list_6021654_air...uirements.html

[jtpitkin06]

Commercial airlines aircraft usually have two vhf transceivers. One is used for ATC communications and the other monitors ARINC (Aeronautical Radio) which is a private company that connects the individual company with the aircraft) 121.5 is simply not monitored.

I flew the last 23 of my 38 year career with AA. #2 com was used for clearance delivery, ATIS and ramp control when on the ground. In the air it was almost always monitoring on 121.5. There was no need to monitor ARINC frequencies as the ACARS would do that for you on a third VHF receiver or you would get the call via SATCOM. ARINC voice is rarely used when in domestic airspace because the ACARS spits out a paper message or displays it on the FMC.

Center would often ask if we could hear an ELT. If present, we could hear it for 100 miles or more by adjusting the squelch. So airlines do, in fact, listen to 121.5 and can pick up the signal for much further than a few miles. The airlines monitor not just for ELT's, but for voice calls as well. If someone makes an emergency voice call on 121.5 it may be the only signal received. We've already proven that both 121.5 and 406 beacons, as good as they are, don't always activate.

While 121.5 ELT's have limitations they can be picked up by almost any GA aircraft with a VHF radio. None of the radios installed in airliners or my personal aircraft receive 406 MHz. We rely on satellites to do that. Hmmm... how dependable is my satellite TV or internet when it rains?.

So, what do I have in my Kitfox and Cardinal? I have 121.5 ELT's. Why did I put a 121.5 in the Kitfox? Because it was free from someone upgrading their C210. When the current batteries go out of date, I'll probably put the money toward a new 406 as it is obviously a better unit for locating a downed aircraft. As a bonus, the 406 uses D cells which are a whole lot cheaper than the proprietary battery packs. It might take five or six cycles, but the 406 will eventually pay for itself in battery costs.

I would like to add the following suggestions.

1. If you are flying about and not using your radio, don't just turn down the volume... tune it to 121.5 and monitor.

2. If you are going down, broadcast on 121.5 and give your position several times. If you get contact with someone, stay with them. If no contact and/or just before touchdown, activate the ELT with the remote switch. Don't count on that G switch in the orange box to do it for you.

3. If you hear a distress call on 121.5 and either ATC or FSS does not respond, relay the information to ATC.

4. Remember, you do not have to be on fire to use 121.5. If you lose contact with ATC and can't find a working frequency, try 121.5. Some ATC or FSS will probably answer and get you on the correct freq. No fault, no foul.

John Pitkin
Greenville, TX

[kitfox5v]

Thanks John for your input. Great to have you on the forum. Spot-on.
Eddie

[PapuaPilot]

The real issue with 121.5 ELTs is that even if they are broadcasting from an aircraft someone still needs to do SAR to try and find the downed plane before the ELT batteries die. Typically you have 48 hours before they are dead. This requires special equipment and people that know how do home in on the signal.

Some problems with searching for 121.5 ELTs are:
You need to find someone that has equipment to home in on the signal
They are line of sight
In mountains you get bouncing signals which makes it VERY difficult to find a plane
Night time is usually lost time while the battery is being depleted
Bad weather can hamper SAR activity while the battery is dying
ELTs don't do any good if the plane goes into water, doesn't activate or if the antenna/cable gets broken on impact or from fire

Time is the real factor if you are looking for a downed plane. Every minute counts. This is where the 406 ELT really shines. When a satellite picks up the signal you know the aircraft's identification, position and people are being alerted. If the 406 ELT has GPS input then you have the exact position of the plane. It only takes one time to get the data to the satellite. If the pilot turns on the ELT before going in then the satellite can show the track of the plane till touchdown. The SAR planes can go right to the point of impact with great accuracy.

PLBs are good to have, but they don't replace the ELT. If you are incapacitated or dead the PLB won't do you any good whereas the 406 ELT should allow SAR to find your plane.

If you do any flying in the back country, remote areas, over water, etc. the 406 really makes sense. I already have installed a 406 ELT in my Kitfox 5 and will probably buy a PLB too.

[HighWing]

Definitely not an expert on this subject and appreciate all the informed comments. My story: When deciding whether to simply comply with the regs or to spend the bucks. I was talking to a friend who rides motorcycles. I asked his thoughts. His perspective on the legal aspects vs. the practical was pretty much the same as we face as helmets are required by law in California for motorcyclists and price and quality run the gamut. His comment, "You don't want to be in the ambulance on the way to the hospital wishing you had bought the more expensive helmet." I took his advice.

[Danzer1]

Lowell,

I like the analogy, out here in the wild West (Colorado) helmets are not even required when riding, but eye protection is (go figure) I guess they want you to be able to see what caused your noggin to get crushed! A whole nother controversial topic though. My riding group has only a three rules, respect everyone else on the road, don't cause a scene anywhere and anyone can ride with us but you have to wear a helmet and appropriate riding gear. Maybe that's four.

If your (not you personally - anyone reading) one of those that thinks the ELT requirements are "in the way" of your personal rights - go buy/build a single seater!

[cap01]

having been involved with sar for several years up here on the left coast , i became well aware of the weakness of the the 121.5 elts . also i was personally involved with two searches where the pilots survived the crashes but expired due to the elements . the searches for them both had been delayed for several days because of weather in the mountains . had the 406 elts been available at the time its pretty certain at least one of them wouldn't have had to die .
the majority of my flying now is in the hills or mountains and i carry a plb . its not uncommon out her for hikers or climbers to become lost or injured several times a year . some of these searches require tremendous amounts of sar resources . guess i don't understand why the park service doesn't require these people to have a plb . for what it costs to launch one chopper you would think the park service could issue a years worth of plbs to anyone that they issue a permit to .
i guess what it comes down to is a choice between what is required and what a person feels comfortable with .

[Timberwolf]

Danzer, I wasn't necc taking an issue with you, but with the information you posted off of wikipedia. There was no set standard for transmission power and it never was transmitting voice from a 121.5 ELT. I was never arguing that the 406 elts aren't an all around better product. The 406 elt/plb sends out a satcom burst with personal information and for the newer ones, gps position. However for the COSPAS sat network, if the sat is low on the horizon, a 5 watt omni directional beam is still going to have issues getting to the sat. Hopefully on the next transmission it would get the information to the sat. However, this is still a LOS system and you must have a clear view of the sky.

It is still up to the owner of a KF if they want to install a 121.5 or a 406 ELT, but they must have one unless it is a single place aircraft. I think you will find that most of the people nowadays that do any back country exploring have a PLB capable of sending messages and position so friends and family can track them. As a few recent incidents have proven, you can alert a friend that you are stuck at XXX with a broken tailwheel spring and need some help. SPOT and InReach are 2 of the most popular systems. So even for those who keep a 121.5 ELT, it may not be a bad idea to keep a PLB on your body at all times if something bad were to happen.