Date: 202201
Local time of day: 1201-1800
Location: ZZZ.Tower, US
Flight conditions: VMC
Light: Daylight
Aircraft: Citation II S2/Bravo (C550)
Operator: Corporate
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class B ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Normal Brake System
Component problem: Malfunctioning
Reporter organization: Corporate
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Human factors: Troubleshooting
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action; General Flight Cancelled / Delayed
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Upon approach to ZZZ we configured normally; the indications of a power brake failure are always illuminated upon landing gear extension. However; they extinguish after the power brake accumulator reaches sufficient pressure. The lights did not extinguish; indicating an actual power brake failure. We told ATC we needed to go missed and troubleshoot. We went missed to the west and took vectors. We did not retract the gear since we would be unable to troubleshoot the power brakes with the gear retracted. After running the manufacturer abnormal checklist we had determined we would be landing with only emergency braking. While on vectors; I transferred controls to the non flying pilot and briefed that I would be briefing the passengers in the cabin of our precautionary landing and what to expect. I did not want them to panic and do something out of the ordinary. They were briefed and calm when I left for the flight deck and knew what to expect. We accepted vectors for the ILS runway XX and landed normally in normal configuration. We stopped the aircraft as briefed without using the emergency brake lever as it was not necessary; but was available if we needed it. We hand landed and stopped within 5;000 feet of a 12;000 foot runway. Crash and fire rescue (CFR) approached and chocked us per our request since we had no parking brake. I exited the aircraft normally and spoke to CFR. After we had determined the area was safe the passengers asked to exit; which they did. Airport ops offered to give our passengers (pax) a ride to the FBO along with their luggage; I thanked them for that. The pax left and we waited for a tug to remove us from the runway and take us to the FBO. I asked CFR if they needed any information; they said they did not. The aircraft was written up for a power brake failure upon arrival to the FBO; Chief Pilot and Director of Operations were contacted due to notifying ATC. After they were informed; Maintenance was called to address the  issue and normal maintenance procedures began.I believe we acted in the best interest of safety; and complied with all established procedures. We as a crew believed notifying ATC was the correct action for an abnormal landing.




Synopsis: Captain reported loss of power brakes during approach to landing. The flight crew went missed approach to troubleshoot before returning to land. The aircraft stopped on the runway and was chocked in place until a tug could be dispatched to tow the aircraft to the FBO for maintenance.