Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Executed Go Around / Missed Approach; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification
Aircraft
Preflight and flight operations had been routine and unremarkable during the Part 91 reposition flight. I was pilot monitoring during the ILS approach. The pilot flying (PF) was using the autopilot to fly the coupled approach. 'Before Landing' checklist had been completed up to the call for landing gear extension. The PF called for landing gear down at the glide slope intercept. The gear extended and locked normally; but as the gear locked in place; the 'PWR BRK LOW PRESS' and MASTER CAUTION lights illuminated. I called out the annunciator lights to the PF and referenced the Abnormal Procedures checklist. The PF executed a go around at approximately 600 ft. AGL while I notified the Tower Controller. The Tower issued us vectors and transferred us to Approach. We requested vectors from Approach while we ran the checklist.  The PF engaged the autopilot and we went through the steps listed for the power brake system failure checklist. The lights remained illuminated at the completion of the initial portion of the checklist. We continued to read through the steps for landing with a failed brake system and briefed the appropriate actions. At that point we decided to divert [to a nearby alternate] to take advantage of the available runway length. We notified the Approach Controller. We continued to brief the actions necessary to comply with the guidance in the abnormal procedures checklist while resetting the aircraft for an approach and landing. We also notified the Controller that we would need a tug to move the aircraft from the runway after touchdown. The PF flew a normal approach to touchdown; called for ground flaps; and applied braking pressure with the emergency brake system. The aircraft came to a full stop on the runway. We advised the Tower that we would need a tug to tow us to the ramp and that no further services were required.
CE-525 First Officer reported landing safely after experiencing a 'PWR BRK LOW PRESS' Master Caution warning on final approach. The emergency brake system was used to stop the aircraft on the runway.