I had the annual check-flight for my IR yesterday and in preparation for this I usually do some re-reading of the POH, check-lists, procedure descriptions etc.
When I had a read through the emergency check-list I was starting to wonder about the ELT in my plane. It is supposed to be automatically activated by a G-force switch in case of a crash but also has a switch in the cockpit with which it could be activated manually.
In case of an emergency, say a forced landing outside of an airfield, would you activate the ELT manually and when, e.g. while still in the air?
Yes, absolutely, use all tools you have.
Just remember one thing. In addition to the 406 MHz signal, most ELTs also transmit on 121.5 MHz, for homing. If your emergency is handled on that frequency, you might just be blocked out by your own ELT.
Apart from that consideration, yes, the ELT “on” switch is mounted in the cockpit for a reason. It’s not just there for testing purposes.
you might just be blocked out by your own ELT
Is this a real issue? I should think the ELT sends out rather short “bursts” of data, with quite some time between them? If only to save on battery life.
I would always turn it on before impact.
you might just be blocked out by your own ELT
That’s what is was wondering about. The manual of my ELT states that it will “… transmit a standard swept tone on 121.5 MHz until the battery is gone…”.
“… additionally, it will transmit every 50 seconds a data burst on 406 Mhz. The transmission on 406 MHz lasts only 440 ms …”
What is a standard swept tone and will it block the frequency?
Otherwise, my thinking would also be to activate the ELT.
Is this a real issue? I should think the ELT sends out rather short “bursts” of data, with quite some time between them? If only to save on battery life.
Out of curiosity I checked to see if YouTube had examples, and they did.
So the signal on 121.5 is a continuous whoop-whoop signal and will definitely influence your ability to communicate (receive) on 121.5.
I can well imagine that the 406 MHz signal is short burst of info indeed, to conserve battery power, but that’s not interfering with 121.5 anyway.
I would always turn it on before impact.
Aviate, Navigate, Communicate. At some point in time during your emergency you’ve got to realize that there’s nothing ATC can do for you anymore. At that stage it’s better to turn the ELT on, and maybe the radio off to prevent distractions.
Some useful info on https://en.wikipedia.org/wiki/File:Radio_beacon_of_distress_on_121,5_MHz.ogg
Apparently the transmission on 121,5 is continuous so yes, it is a real issue.
406 MHz does bursts of 440 mS every 50 seconds – much more reasonable.
I’ve heard ELT’s on 121.5 before while flying. I don’t think that they would interfere too much with communications. And in any case, S&R can easily use other frequencies.
It is most likely you aren’t communicating on 121.5 anyway. I would only turn my radio off to avoid a fire, not to avoid distractions. I wouldn’t turn the ELT on at 15000ft but I would never rely on the impact switch to activate it.
