EMB145 first officer reported parking break failed.

Narrative:

After landing at ZZZ on runway 2; we proceeded to taxi to the gate. Captain was taxiing and we were marshaled into the parking spot assigned. Marshall stopped us on the spot we had to stop; and aircraft halted. Parking brake was set; nonetheless; aircraft started to move forward; I believe 20 feet or so. From inside the cockpit it sounded as if the airplane was overriding the brake pads. It looked like the brakes were stopping the airplane; but not completely; we heard a 'grinding' noise and the aircraft bumped. Captain's reaction was to apply toe brakes. Aircraft stopped and we almost hit the ground-power cart unit on the left side of the airplane. After parking the airplane and running check list; I went outside to check on the rampers. I asked ramp personnel if they were ok; and they were; however they were scared. I proceeded to check the wing and I did not see any evidence of damage. Ground-power cart unit was underneath the wing and we missed it by 1/8 of an inch. Captain called the company to report the parking brake failure. Parking brake failed and this may have caused a fatal incident. Fortunately; this time it did not happen. I will probably be more methodical about the situation. This experience has taught me to be extremely careful and always double check. Although I am not a captain yet; someday I will be; and I will make sure to stop the airplane using my toe brakes; then; I will be more cautious when I set the parking brake.

Original NASA ASRS Text

Title: EMB145 First Officer reported parking break failed.

Narrative: After landing at ZZZ on Runway 2; we proceeded to taxi to the gate. Captain was taxiing and we were marshaled into the parking spot assigned. Marshall stopped us on the spot we had to stop; and aircraft halted. Parking brake was set; nonetheless; aircraft started to move forward; I believe 20 feet or so. From inside the cockpit it sounded as if the airplane was overriding the brake pads. It looked like the brakes were stopping the airplane; but not completely; we heard a 'grinding' noise and the aircraft bumped. Captain's reaction was to apply toe brakes. Aircraft stopped and we almost hit the ground-power cart unit on the left side of the airplane. After parking the airplane and running check list; I went outside to check on the rampers. I asked ramp personnel if they were ok; and they were; however they were scared. I proceeded to check the wing and I did not see any evidence of damage. Ground-power cart unit was underneath the wing and we missed it by 1/8 of an inch. Captain called the company to report the Parking Brake failure. Parking Brake failed and this may have caused a fatal incident. Fortunately; this time it did not happen. I will probably be more methodical about the situation. This experience has taught me to be extremely careful and always double check. Although I am not a captain yet; someday I will be; and I will make sure to stop the airplane using my toe brakes; then; I will be more cautious when I set the parking brake.

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.

Attributes
ACN	1607495
Time
Date	201901
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Parked
Flight Plan	IFR
Component
Aircraft Component	Parking Brake
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Ground Event / Encounter Other / Unknown