To reset the NOSE DOOR OPEN CAS message, which sequence is correct?

• A. Go Outside and Unlatch All 4 Latches, Open Door Fully, Then Close and Latch Door, Lock Key Lock
• B. Open Door From Inside and Reset CAS Button
• C. Use In-Cockpit Reset Procedure Only
• D. Contact Maintenance and Do Not Attempt Reset

Answer: (A)

The key idea is that the Nose Door Open CAS alert requires a physical, outside-the-aircraft reset of the nose door mechanism. You must go outside, unlatch all four latches, open the door fully to confirm it’s not stuck, then close and re-latch the door and lock the key lock. This cycles the mechanical and sensor state properly, allowing the system to recognize that the door is securely closed again and clear the CAS message. Using an inside reset or a cockpit button won’t affect the external latch state or the door-position sensors, so they won’t reliably clear the alert. Similarly, contacting maintenance is prudent if you suspect a deeper fault, but when the procedure is specified, the external latch-cycle is the correct reset method.