G.P.S.
From SLF newbie. Having read this whole thread twice and being impressed by all the thoughts and skills brought to bear on this terrible tragedy,it appears not to have reached any serious conclusion. However,reading up on GPS in Wikepedia in the 'Basic Concept of GPS' paragraph the article states "Some GPS Receivers may use Additional clues or assumptions (such as using the last known altitude,dead reckoning,inertial navigation,.......)to give a degraded position when fewer than four satellites are visible.(see notes) end of quote. Given that the plane might have been in trouble and descending in various attitudes at the last ACAR transmission,could this position be degraded,and if so does the loss of height vary the position calculated by the GPS unit./ Sorry for the lack of technical termanology,I am not a flier only a passenger.