Citation Excel (C560XL)
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human-Machine Interface; Situational Awareness; Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Overcame Equipment Problem; General Maintenance Action
Aircraft; Human Factors
At cruise altitude of 38;000 ft. the master caution and cabin door light illuminated. Took out the emergency checklist; discussed the issue with the Captain. Performed the checklist in detail. Didn't [request priority handling] and elected to continue the 45 minutes to destination. On descent the cabin altitude creeped to 10;200 ft. and the master warning light illuminated with the red cabin altitude annunciations illuminated. The pilot flying acted as [if] a rapid depression was imminent and began increasing our descent rate and deployed the cabin oxygen masks for our passengers. I looked immediately to the pressure controller and noted the cabin altitude stable and about 10;200 ft. I toggled the manual control back to 9;500 ft. and the cabin altitude warning light extinguished. We secured and discontinued using oxygen [for] both pilot and passengers [and] continued to ZZZ and wrote up the system malfunctions.Two suggestions: 1; add a note to the checklist identifying the need to constantly monitor the cabin altitude and manually adjust accordingly so as to not inadvertently get a master warning and cabin altitude warning annunciator. And 2; perhaps a random check of the fleet to see if the passenger oxygen masks in fact deploy when activated by a cockpit crew member. [Also] upon deploying the passenger oxygen we noted the infant masks did not release and subsequently did not deploy. Also the masks in the lavatory section failed to drop.
A Citation Excel First Officer reported rising cabin altitude; master caution; and cabin door warnings which resulted in deploying oxygen. Some masks failed to deploy.