7 OUTLINE THE STRUCTURE OF RECOVERY BLOCK SOFTWARE TO COPE WITH THE...
17.7
Outline the structure of recovery block software to cope with the following situation.
A fly-by-wire aircraft is controlled by software. A normal algorithm calculates the opti-
mal speed and the appropriate control surface and engine settings. A safety module
checks that the calculated values are within safe limits. If they are not, it invokes an
alternative module that calculates some safe values for the settings. If, again, this
module fails to suggest safe values, the pilots are alerted and the aircraft reverts to
manual control.