General Authority of Civil Aviation (GACA) Aeronautical Information Publication (AIP) Practice Exam

Moving the primary flight computer switch to 'DISC' is significant because it disconnects the primary flight computers (PFCs) from the flight control system and puts the aircraft into DIRECT mode. In this mode, the fly-by-wire system no longer processes commands through the PFCs, which allows for direct control of the flight surfaces. This can be useful in situations where the pilot needs to bypass certain automated functions or when there is a malfunction affecting the normal operation of the PFCs.

In DIRECT mode, the response of the flight controls can become more immediate and may allow pilots to perform maneuvers that might be restricted under normal conditions governed by the PFCs. This action is particularly crucial for maintaining control of the aircraft when faced with system failures or malfunctions. Therefore, this choice accurately reflects the operational implications of selecting 'DISC' on the primary flight control system.