AC90-100A operations must not be conducted with any of the following messages displayed. Which single option listed is an example?

AC90-100A operations must not be conducted with any of the following messages displayed. Which single option listed is an example?

• A. NO GPS RAIM
• B. GPS SIGNAL LOST
• C. GPS DISABLED
• D. GPS-FMS DISAGREE

Answer: (A)

GPS integrity and RAIM availability determine whether AC90-100A operations may proceed. The message NO GPS RAIM means the Receiver Autonomous Integrity Monitoring system cannot verify the GPS data integrity for your current position. Without a valid RAIM check, you cannot rely on GPS for the navigation requirements under AC90-100A, so operations using GPS in this context must not be conducted. Other messages indicate GPS issues but do not specify the required integrity verification that AC90-100A prohibits. For example, GPS SIGNAL LOST means the receiver temporarily has no satellite signal, GPS DISABLED means the unit is manually turned off, and GPS-FMS DISAGREE indicates a mismatch between GPS and the Flight Management System data. These situations require different procedures or rechecks, but the explicit prohibition tied to AC90-100A operations is the absence of RAIM.

GPS integrity and RAIM availability determine whether AC90-100A operations may proceed. The message NO GPS RAIM means the Receiver Autonomous Integrity Monitoring system cannot verify the GPS data integrity for your current position. Without a valid RAIM check, you cannot rely on GPS for the navigation requirements under AC90-100A, so operations using GPS in this context must not be conducted.

Other messages indicate GPS issues but do not specify the required integrity verification that AC90-100A prohibits. For example, GPS SIGNAL LOST means the receiver temporarily has no satellite signal, GPS DISABLED means the unit is manually turned off, and GPS-FMS DISAGREE indicates a mismatch between GPS and the Flight Management System data. These situations require different procedures or rechecks, but the explicit prohibition tied to AC90-100A operations is the absence of RAIM.