Soft Walls - Modifying Flight Control Systems to Limit
the Flight Space of Commercial Aircraft

Edward A. Lee

Revised from UCB/ERL Memorandum M001/31
University of California,
Berkeley, CA 94720, October 3, 2001.



Many things changed on September 11, 2001. Among them, civilian aircraft became potential enemy weapons systems, and air traffic control changed from a civilian problem to a military one. This working document describes a technological response that is practical and implementable and goes a long way towards ameliorating the risk of a repeat.

This is a working document, far from complete.

(Earlier version)