A 1996 crash that killed U.S. Commerce Secretary Ron Brown drew attention to a problem that has caused thousands of airline fatalities.  Controlled flight into terrain (CFIT) results from an autopilot driven by erroneous information regarding aircraft‘s flight path relative to its surroundings.  This writer narrowly escaped death in early January 1981 when an errant foreign airliner very nearly collided with the World Trade Center (that time it would have been accidental); an alert air traffic controller issued a turn directive just in time.  A highly informative IEEE-AES Systems Journal article by Swihart et.al. —
…. “Automatic Ground Collision Avoidance System Design, Integration, and Test” (May 2011, pp.-4-11)
addresses CFIT while envisioning, near the end, future extension to unmanned aircraft.  The authors correctly describe the effort as the beginning of a long-awaited development with a huge payoff in lives to be saved and, secondarily, in vehicles not destroyed.  As proof of my full concurrence — both with the intent and with the “long-awaited” characterization — I cite the following:

* a “GPS for Collision Avoidance” seminar I prepared in 2000 (hardly anyone attended — no funding, no interest — but safety shouldn’t take a back seat to economics).
* two coauthored papers (ICNS 2009 and ION-GNSS-2011) resulting from recent low-level support to Ohio Univ. by NASA.


It remains true to this day: much more needs to be done.  Without significant increase in development, life will be increasingly hazardous.  Both heavier traffic and unmanned aircraft will contribute to the increased danger.