As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: BRAKE PEDALS SPONGY AND UNRESPONSIVE AT INITIAL APPLICATION THEN GRAB EXCESSIVELY AS PEDAL PRESSURE IS INCREASED - MAINTENANCE ACCOMPLISHED FILLING AND BLEEDING OF ALT BRAKE SYSTEM PER AMM TASK 32-43-00-612-001-A. - MAINTENANCE PURGED LARGE AMOUNTS OF AIR FROM THE SYSTEM AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK PER AMM 32-43-00