Citationjet (C525/C526) - CJ I / II / III / IV
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Troubleshooting
Aircraft Equipment Problem Critical; Ground Event / Encounter Other / Unknown
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
We did our before start checklist and started the engines. Once the engines were started and the chocks were removed the parking brake was released and the airplane started to roll. I looked down at the Captain's feet and he pressed the brakes and the airplane continued to roll I then immediately pressed my brakes and the airplane didn't stop. The Captain then turned the engines off and pulled the emergency brake until the airplane came to a complete stop. The airplane was the chocked and secured. Really there was nothing we could've done. Good thing is it was caught before anything major could've occurred.
C525 First Officer reported brake system failure after engine start before taxi.