Date: 201905
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Aircraft component: Parking Brake
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Situational Awareness; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew; Person Maintenance
When detected: Aircraft In Service At Gate
Result: General Maintenance Action
Contributing factors: Company Policy; Aircraft; Human Factors
Primary problem: Aircraft

Narrative: On flight XXXX we arrived in ZZZ and received an EMRG BRK LO PRES EICAS (Engine Indicating and Crew Alerting System) message after engine shutdown. As I called Maintenance Control the Brake On light also went out. Maintenance came out and serviced the hydraulic system 2 accumulator. The EMERG BRK LO PRES EICAS message still came on shortly after turning off hydraulic pump 2. The Brake On light also went out about 5 minutes after the EICAS message. Maintenance worked with Maintenance Control; who believed the issue was an indication problem. I've experienced a similar situation before and was concerned that; like those times; this may not be just an indication problem. I spoke to the Chief Pilot who said he would call and talk to Maintenance Control on his end. I also expressed my concern to the Mechanic. He thought the issue was an indication problem; but unlike any Mechanic I've experienced parking brake problems with before; he figured out a simple way we could check the parking brake together and know for sure.He said he had a jack in the truck; and we could jack a set of main gears up and see if the wheels could be spun with the parking brake set. In this case the wheels did spin; so he knew there was a problem with the parking brake that needed further troubleshooting. If the wheels had not spun I would have been confident that the parking brake issue was an indication problem and felt comfortable flying with the MELs. First I want to give the Mechanic a lot of credit for coming up with a simple and quick way to test whether the problem was with the parking brake indications or with the parking brake itself. In all the times I've seen this problem before I've never had a Mechanic problem solve this issue so simply and so quickly. Second; I'm seeing this particular problem with the parking brake a lot lately. Whatever the cause; there's something going on frequently enough that it needs to be looked into and discussed with the pilots and mechanics. If I hadn't seen this problem before this aircraft would have been flying around with 2 indication MELs and a parking brake that wasn't working for the required 24 hours or 6 applications once the hydraulic pump was shut off.The threat is a parking brake that wasn't functioning properly that could have resulted in the injury of ramp crews. The difficulty with this threat is determining whether the parking brake really isn't working or if it's a brake indication problem. The company needs to put out guidance to pilots and mechanics on how to differentiate between parking brake indication problems and actual parking brake problems.




Synopsis: EMB-145 Captain reported maintenance personnel were able to determine a parking brake indication issue was valid while parked at the gate.