An acquaintance of mine, along with her fiance and the pilot, were killed last year on a small aircraft flight through the Rocky Mountains. The aircraft ELT didn't go off, so their deaths were not confirmed until over a month later, when by a fluke, a local hang-glider pilot happened to spot the wreckage from the air.

I got to wondering, if I'd been aboard that aircraft and realised, too late, that the pilot was an idiot. (He had only flown that route once or twice before, and he took off between two frontal systems, meaning he had bad weather in front and bad weather closing in behind; stupid enough anywhere in the world, it was downright suicidal when trying to follow a highway through a mountain pass.) If I had a PLB, when would I activate it so that the rescuers would at least have a decent shot of finding my body? Would I just activate it for the duration of the flight, and turn it off and apologise to the authorities when/if we landed safely? Or would I have it clutched in my hot little hand, my finger on the trigger, ready to activate it as soon as a crash landing was imminent?

What if I was the pilot, and I blundered into a "Toto I don't think we're in Kansas anymore" type scenario? Now I've got my hands full flying the plane; should I just activate the device and forget about it?

Ideally, what I'd like to have is a timer switch that will activate the PLB in, say, 30 minutes unless I reset it (preferably with a nice, loud, annoying beeping sound for 5 minutes before it goes off). I'm inclined to doubt that any commercial PLB currently has such a feature. Am I wrong?

What are the pros and cons of such a mechanism?

The idea of a PLB is it lets rescuers find you, often at considerable risk to themselves, while you're still alive. If you're already dead you should not put them at risk just to find your remains.

The correct action for the pilot would have been get on the radio (or satellite phone) and tell someone on the ground that there was trouble.

Rather than a dead-man switch I don't understand why PLB's can't send more different kinds of messages than "I'm in unspecified trouble, send help immediately!". It could have a message selector that lets you choose between "This is an advisory update, my location is [coordinates] in case something happens, but everything is fine"; "I'm having some non-emergency difficulty; my expected arrival is delayed but don't send assistance unless I fail to check in again within 12 hours", "My plane is about to crash and I will be a pancake within the next 60 seconds; no point endangering rescue crews to scrape me off the mountainside but you might send someone to look for wreckage when the weather gets better", etc.

paulr: I respectfully disagree.

1. Search and Rescue planes overflew the crash site at least twice without spotting the wreckage. They had no way of knowing whether the pilot and passengers were still alive; they just kept searching until they had exhausted any reasonable hope of finding anyone alive. Had the ELT been functioning, or had one of the passengers set off a PLB, the search would have concluded days earlier, with the obvious result being far less risk to the searchers.

2. I could be injured, trapped, or unconscious. In such a case, having my PLB sending out a distress signal to expedite rescue would be a high priority.

3. As trite as it sounds, knowing that a loved one is dead is, for most people, preferable to knowing that they're *probably* dead.

4. Who in their right mind is ever going to activate a signal that says "Don't bother looking for me"? (Fwiw, the recommended procedure if you make an emergency off-airport landing and don't need immediate medical help, but have no way of contacting anyone to tell them you're okay, is to wait until the SAR time on your flight plan (normally about 1 hour after your ETA) and then manually activate your ELT. This saves batteries and will shorten the time spent on Search and Rescue as much as is feasible.)

5. What SAR team will risk the bad publicity and potential lawsuits if they detect a beacon from a downed plane and DON'T go in to investigate? No SAR professional is ever going to assume that there are no survivors, regardless of the kind of beacon, unless he/she sees for him/herself.

6. Imagine the potential litigation if someone pressed the wrong button and sent out the "don't bother looking for me" signal instead of the "my passenger is slowly bleeding to death from a severed artery" one? <img src="images/graemlins/ooo.gif" alt="" />

I've often thought that it would be wise to carry a PLB while flying especially because ELTs have such a bad record in crashes. They rarely go off in the type of crash your friend was probably involved in.

I think the critical question is when does one declare an emergency. In general, it seems pilots are afraid to declare an emergency early enough for it to make a difference and in that regard I'm not sure a PLB would be treated any different than a verbal MayDay in the minds of most pilots. Still, I think carrying a PLB makes more sense than relying on the so often unreliable ELT alone. But then, all the technology in the world is not going to save a pilot from making incredibly stupid decisions like the pilot of your friend's airplane made.

This is a pretty good story about a small plane ditching:

http://www.equipped.org/1199ditch.htm

Crucial to the story is that the pilot notified the coast guard by radio as soon as the engine trouble started (hours before the engine actually stopped). That seems to be what's missing from that ELT picture. I defer to the wisdom of you old timers about whether ELT should be activated when the plane's occupants are already probably squashed.

I thought also that all planes were supposed to have "black boxes" that broadcast a locator signal. Is that just for big airliners?

In Canada and I assume the USA as well as our regs are almost identical to yours all light airplanes operating outside a 25 nautical mile radius of their home airport must be equipped with an ELT (Emergency Locator Transmitter), unless it has been removed temporarily for repairs. The problem is the devices, which are set to automatically turn on after high forward G Forces, are notoriously unreliable.

The so-called "black boxes" are only carried on airliners but their purpose is to enable the accident investigators to determine what went wrong. There are usually two - the cockpit voice recorder and the flight data recorder.

As Paula has pointed out, all aircraft (except ultralights, and possibly balloons and gliders) are required to carry Emergency Locator Transmitters (ELTs) which activate in the event of a crash. Sometimes a hard landing will set them off, but they still seem to have a very high failure rate.

I once worked in the Intelligence section of a Canadian air force base. I didn't work closely with the SAR Techs but I did have the chance to speak with them from time to time. Their major complaint was having to risk their lives unnecessarily to save someone who'd done something stupid (e.g. fishermen who put out to sea with known medical problems, figuring if their condition got worse, they could always "phone for a lift", as it were).

But I never, ever, heard of one refusing to go to a crash scene if there was any possibility of someone still being alive; and there's always that possibility unless you've ruled it out by direct observation.

As an example, see the transcript of the police debriefing of air rescue paramedic Kristy McAlister following the 1998 Sydney-Hobart Yacht Race disaster.

http://www.equipped.org/sydney-hobart/Volume%2001.htm

McAlister's crew rescued 4 people off a yacht that was sinking in gale force winds. The following day, in much calmer weather, they were patrolling the area when they picked up a distress beacon. (There were dozens of abandoned yachts whose beacons were still active, each of which had to be investigated.) They found the yacht and observed a body lying on deck, and McAlister was preparing to go down and rescue him when they were told not to bother, the person had drowned the day before when the yacht capsized. Later, when she found out that no medical professional had, in fact, examined the man, she was extremely distraught, because she felt that it was her job as a paramedic to be winched down to confirm that the dead man really was dead.

Generally, the easier it is for them to find you, the fewer risks they have to take.

aardwolfe - your last point about litigation possibilities is right on. NO manufacturer is going to give people who are already stressed by being in an emergency situation (and hence setting off their PLB) the luxury of choices, because that can come back and haunt them with the possibility of big $$$$$ lawsuits. For example, "Now, Mr. PLB manufacturer, if you had a button for 'Come get me right the heck now!', why didn't you have a button for '*fill in the blank*'? Wouldn't that have been reasonable?" You can see where this is heading - in today's legal climate, more choices equals more legal risk for the manufacturer. Pathetic, but that's the state of affairs, at least in the USA, where people who gorge themselves at McDonald's have actually tried to sue that company for making them fat...

By that logic, cellular phones shouldn't be able to call any numbers other than 911.

Not really. PLBs are, at present, designed to do one thing - help you get found in an emergency. Cellular phones are designed to be two- way (or more) communications tools, and now cameras, memory sticks, etc., etc...