It's worth adding a couple of points.
If the power is abruptly removed from the Spidertracks unit without the correct shutdown sequence, the ST servers can be set to automatically send an alert.
It is also possible for the pilot to press an emergency-only button to generate an instant alert.
In case it's not obvious from the previous posts, Spidertracks uses satellite phone technology so is not dependent on cellphone infrastructure to send its messages.
Last edited by Oktas8; 1st Jun 2012 at 08:22.