Which statement best describes how satellites can be deselected for use?

• A. You must enter the satellite's identifier on the FMS GPS control page.
• B. You can only deselect satellites via the EGPWS.
• C. You can deselect satellites only from the cockpit controls.
• D. You cannot deselect satellites in flight.

Answer: (A)

Deselecting a satellite is done by managing the GPS receiver through the FMS, specifically on the GPS control page. There you enter the satellite’s identifier (the satellite PRN) to disable it from use. This precise method directly tells the system which satellites the GPS should ignore, which is why it’s the correct approach.

EGPWS is a terrain awareness system and has no function for selecting or deselecting GPS satellites, so it can’t be used for this purpose. Saying you can only deselect satellites from cockpit controls isn’t accurate here because the official procedure relies on the FMS GPS control page to control satellite usage. And the notion that satellites can’t be deselected in flight isn’t correct in general, since the FMS interface typically allows changes to which satellites are used while airborne.