Narrative:

Upon reaching 10;000 ft. We noticed that our pressurization needle spiked a couple of times. After a brief crew discussion; we decided to request a deviation to ZZZ for a maintenance check. After discussing the issue with the staff they informed us that they wouldn't be able to address it until the following week. The pilot in command (PIC) contacted a former maintenance colleague to ask for advice. They told him that it sounded like an outflow valve had stuck and that it's not uncommon and that we should fly the plane and cycle it again. We filed for 11;000 feet and departed. Staying low and with oxygen mask in hand with frequent donning; we cycled the pressurization system and everything was working fine; so we requested 15;000 for the remaining distance to ZZZ2. After refueling at ZZZ2. We filed for 20;000 direct to ZZZ3. We departed ZZZ2. Again no problems with the pressurization system so we requested 29;000 for the remaining distance; being cautious with mask in hand and frequent donning; we had no issues with the system. When we were at 29;000 about 10 miles southeast the PIC asked me to check the hydraulic pressure gauge located on my side of the panel. Upon inspection I confirmed and reported to him that it was at 'zero' psi and that the hydraulic fluid volume was dropping as well. We immediately got out the emergency checklist and ran through the procedure for loss of hydraulic pressure. After more than one attempt we contacted ATC and told them the situation and they asked us what we would like to do as far as a deviation. We told them that we would discuss and get back to them because we had plenty of fuel to allow us to work out the problem. We then contacted them and requested a deviation to ZZZ4 because it was a very familiar airport with a 10;000 ft. Runway knowing that we would not have use of the conventional brakes and thrust reversers. After arriving into airspace near ZZZ4 we slowed the airplane down to below vlo and went through the emergency procedures for emergency gear down. After activating the hydraulic bypass valve located in the aft lavatory and then deploying the emergency nitrogen gear blow down via the t-handle; only the nose gear came down. Between the PIC and myself we deployed the t-handle no less than 30 times while noting that the checklist and placard both cited pulling the t-handle out and turning it clockwise. It would not turn clockwise and we feared that pulling with excessive pressure could break it. ATC requested that we fly by the tower to confirm the gear and they confirmed that we had the nose gear down and the mains were still up. After their confirmation they informed us that they contacted a service center and that the advice was to grab the handle with both hands and pull as absolutely hard as one could. Upon receiving those instructions; I did just that and the main gear came down with three green lights displayed. We then informed ATC of our success and they requested that we fly by the tower again to confirm. ATC confirmed that we had the nose and main gear down so we requested to land. Upon a successful landing the PIC deployed the emergency brake (which is also powered by a separate nitrogen bottle) and we reduced our speed to a taxi. About mid-field the PIC decided to exit the runway via a taxiway in order to clear a commercial airport that had been shut down for almost and hour and a half. After exiting the runway the PIC deployed the emergency brake one more time however there was no response other than the aircraft veering to the right and striking two unoccupied aircraft on the ground. After striking the aircraft at a taxi pace the PIC shut down the engines and we came to rest. The series of events just described are to the best of my recollection at the time of the incident.

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Original NASA ASRS Text

Title: CE-650 First Officer reported problems with the hydraulics systems. Normal braking was not available and resulted in loss of control during taxi after landing.

Narrative: Upon reaching 10;000 ft. we noticed that our pressurization needle spiked a couple of times. After a brief crew discussion; we decided to request a deviation to ZZZ for a maintenance check. After discussing the issue with the staff they informed us that they wouldn't be able to address it until the following week. The Pilot in Command (PIC) contacted a former maintenance colleague to ask for advice. They told him that it sounded like an outflow valve had stuck and that it's not uncommon and that we should fly the plane and cycle it again. We filed for 11;000 feet and departed. Staying low and with oxygen mask in hand with frequent donning; we cycled the pressurization system and everything was working fine; so we requested 15;000 for the remaining distance to ZZZ2. After refueling at ZZZ2. we filed for 20;000 direct to ZZZ3. We departed ZZZ2. Again no problems with the pressurization system so we requested 29;000 for the remaining distance; being cautious with mask in hand and frequent donning; we had no issues with the system. When we were at 29;000 about 10 miles Southeast the PIC asked me to check the hydraulic pressure gauge located on my side of the panel. Upon inspection I confirmed and reported to him that it was at 'zero' psi and that the hydraulic fluid volume was dropping as well. We immediately got out the emergency checklist and ran through the procedure for loss of hydraulic pressure. After more than one attempt we contacted ATC and told them the situation and they asked us what we would like to do as far as a deviation. We told them that we would discuss and get back to them because we had plenty of fuel to allow us to work out the problem. We then contacted them and requested a deviation to ZZZ4 because it was a very familiar airport with a 10;000 ft. runway knowing that we would not have use of the conventional brakes and thrust reversers. After arriving into airspace near ZZZ4 we slowed the airplane down to below VLO and went through the emergency procedures for emergency gear down. After activating the hydraulic bypass valve located in the aft lavatory and then deploying the emergency nitrogen gear blow down via the T-handle; only the nose gear came down. Between the PIC and myself we deployed the T-handle no less than 30 times while noting that the checklist and placard both cited pulling the T-handle out and turning it clockwise. It would not turn clockwise and we feared that pulling with excessive pressure could break it. ATC requested that we fly by the tower to confirm the gear and they confirmed that we had the nose gear down and the mains were still up. After their confirmation they informed us that they contacted a Service Center and that the advice was to grab the handle with both hands and pull as absolutely hard as one could. Upon receiving those instructions; I did just that and the main gear came down with three green lights displayed. We then informed ATC of our success and they requested that we fly by the tower again to confirm. ATC confirmed that we had the nose and main gear down so we requested to land. Upon a successful landing the PIC deployed the emergency brake (which is also powered by a separate nitrogen bottle) and we reduced our speed to a taxi. About mid-field the PIC decided to exit the runway via a taxiway in order to clear a commercial airport that had been shut down for almost and hour and a half. After exiting the runway the PIC deployed the emergency brake one more time however there was no response other than the aircraft veering to the right and striking two unoccupied aircraft on the ground. After striking the aircraft at a taxi pace the PIC shut down the engines and we came to rest. The series of events just described are to the best of my recollection at the time of the incident.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.