Once thing I've often wondered, but been too afraid to ask is this:

We're told than many cell phone calls were made from all of the aircraft involved int he September 11, 2001 attacks, alerting loved ones to the heinous activities that were occuring. The FCC love to scare us with stuff like "if you use your cell phone, it will interfere with navigational instruments and cause aircraft instability". My question is - Did it?

If one person using one cell phone can apparently affect the stability and avionics on an aircraft, what can 30 pax using 30 cell phones do ? Did these phone calls at all affect the stability of the flights?