From: henry@spsystems.net   
      
   In article ,   
     wrote:   
   >Both MEMS devices are good enough for in atmosphere flight where you   
   >can use GPS and the gravity vector to remove the errors.   
   >You can assume that the 1Gee gravity vector is aways there   
   >(or will return shortly after brief periods of non 1 G)   
      
   Unfortunately, it's perfectly possible to have a nice clean 1G while the   
   aircraft is doing something very unpleasant and imminently fatal.  In   
   flight in the atmosphere, what an accelerometer is measuring is the lift   
   imparted by the wings, **NOT** the gravity vector.  (This is why a good   
   airliner pilot -- or a good airliner autopilot -- can do a substantial   
   turn, banked to a fair angle, without spilling your drink.  The drink is   
   responding to lift, not gravity.)   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)