Why Can Pilots Still Turn Off Their Transponders?

MarkRohfrietsch said:

Others have answered why transponders can be turned off; they are correct. You speak of another system; that they have also. They are called Emergency Location Transmitters (ELTs) These have independent battery power and activate automatically in a crash. Bach when I flew they were just coming into use in General Aviation. The early ones worked so well that they sometimes activated as a result of a hard landing, or high G loading during aerobatics. The FBO at our local airport got at least one "do you know where your aircraft is" call a month from the MoT. I think that they have improved greatly since then.

Why they did not function in this case is thus far not known.

Here is a link to info from one company's ELTs for commercial aircraft: ELTs for Commercial Aircraft

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OGM said:

I would simply embed the location and altitude info in to the ACARS data stream. If something out the ordinary happened or when manually triggered...The system could transmit location every 20 or 30 seconds if external power was feed to the unit. If it was runiing on batteries. It could transmit every minute or so.

A plane with a ground speed of 600MPH is moving 10 miles per minute. Hence I would want frequent updates sent if an unusual condition was detected.

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OGM said:

I would simply embed the location and altitude info in to the ACARS data stream. If something out the ordinary happened or when manually triggered...The system could transmit location every 20 or 30 seconds if external power was feed to the unit. If it was runiing on batteries. It could transmit every minute or so.

A plane with a ground speed of 600MPH is moving 10 miles per minute. Hence I would want frequent updates sent if an unusual condition was detected.

Click to expand...