PPRuNe Forums - ELT activation

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superliner

24th Oct 2011 18:12

ELT activation

I just read in the users manual of the ELT's installed on our Cessnas that they are automatically activated at a:

Quote:

velocity change of 2.3 +/- 0.3 G (4.5 +/- 0.5 FPS)

Now I have two points of confusion: if 1G = 9.8 m/s^2 = 32 ft/s^2, so how is 2.3 G = 4.5 FPS? And isn't 2.3g a pretty low value since the airplane itself is certificated to more than that, so in that case don't we run the risk of activating the ELT during 'normal' operations?

Thanks in advance!

Morrisman1

24th Oct 2011 19:49

I have always thought that the ELT was activated from G forces in the longitudinal axis, ie if the aircraft slowed down, causing you to feel 4.5G pulling you forwards off your seat then that is what sets them off.

It would be nice to get some clarification from someone who knows the workings of these

NSEU	24th Oct 2011 21:40

A previous post on ELTs has said that the deceleration forces are spherical (i.e. in all directions).

I would be contacting the manufacturer regarding their questionable values ;)

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