ACARS - Alternate uses...
Had a thought - ACARS (Aircraft Communications and Reporting System) is a functional data exchange system on board most large jet aircraft. As far as I know (pretty little) it reports aircraft parameters such as position, height, temperature, etc at defined intervals.
My question is : can it be remotely polled from the ground ? In the context of Sept 11th, ATC were aware something was wrong and still had a primary paint, but would the other data (height, etc) have assisted them in any way and lead to any alternate courses of action ?