Regional Jet 900 (CRJ900)
Troubleshooting
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Flight Crew Overcame Equipment Problem
Aircraft; Weather
On approach to landing at the Charlotte airport; there was a thunderstorm moving over the Northeast quadrant. The winds were reported at 350 at 8 gusting to 35; so we added 10 knots to our Vref speed. The approach remained stable but with some moderate turbulence all the way to the runway. As we began the flare; we encountered heavy rain conditions. Upon touchdown; reverse thrust and brakes were applied. The reverse thrust worked as usual; however; there was no braking action. I increased the brake pedal deflection to full; but the aircraft still did not respond. At this point the captain and I both realized there was an issue with the brakes; and we ran the appropriate memory items for a braking loss. I released the brakes momentarily; anti-skid was selected to off; and brakes were reapplied. Unfortunately; there was still no response from the brakes. The captain then manually selected the spoilers to full. Both the captain and I continued to apply full brake pedal deflection and maximum reverse thrust until we were sure that we were going to stop. The aircraft gradually slowed and we were able to make the turn off at taxiway C11. The anti-skid was selected back to ON after we stopped. Braking action was adequate for the very short taxi into the ramp. We got an A/SKID OUTBD caution message and an OB GND SPLR FAULT status message sometime during the landing roll. These messages persisted even after shutting down the aircraft. The captain wrote up these messages and contacted maintenance. I believe that this event occurred due to an aircraft system malfunction. The braking system did not respond to pilot input on the landing roll. Aside from the EICAS messages we received; the highest BTMS (Brake Temperature Monitoring System) temperature that was displayed after the landing was a 2. If the braking system had been working; the brake temperatures would have been much higher than this after applying full brakes for a landing. Further; selecting the ANTI-SKID to OFF should have disabled the anti-skid system; which would've caused the wheels to lock up if full braking was applied at a high speed. At the very least; this would've caused bald spots on the tires. During the post-flight inspection of the tires; none of them had any unusual wear; which indicates that the brakes were not applied; even after selecting the ANTI-SKID to OFF. A contributing factor to this event was also the heavy rain/poor field conditions. However; company aircraft that landed immediately before and after us did not have issues with braking; leading me to believe that it was an aircraft specific issue. I'm reporting this event so the company is aware of the possible safety issue from a failing Anti-Skid Control Unit. I believe we as a crew acted appropriately; but there was still a reduced safety margin.
During landing rollout in heavy rain; the crew of a CRJ-900 experienced an initial loss of braking action. Crew received an A/SKID OUTBD caution message and an OB GND SPLR FAULT status message during the landing roll. The anti-skid was selected OFF and then back to ON after stopping the aircraft. Braking action was adequate for their taxi to the ramp.