B737 flight crew reported the parking brake would not release after it was set while holding short o...

Narrative:

Holding short of runway with parking brake set. When cleared for takeoff; I released the parking brake but the airplane would not move. The brakes wouldn't release. We did some troubleshooting in the cockpit and after numerous failed attempts to disengage the brakes we called dispatch and [maintenance]. [Maintenance] had us duplicate what we had already attempted to disengage the brakes but had no success. We notified ATC of our problem when it first happened and after calling [maintenance] we informed ATC that we would be shutting down and waiting for a mechanic to come to the airplane. When the mechanic came; he was also unable to disengage the brakes and he told us that he would have to put the airplane on jacks in order to find the problem. We were in contact with station operations and ATC as to the next step; which was to bring air stairs and busses to deplane the passengers on the taxiway and return them to the terminal. The police and fire came to the plane then the busses and air stairs showed up. The passengers deplaned and the police and fire escorted them to the busses.given the unusual circumstances of this event; I feel that all parties involved did a great job. We provided all the necessary food; water and information to the passengers during this event. We were able to secure another airplane and left a couple hours late.

Original NASA ASRS Text

Title: B737 flight crew reported the parking brake would not release after it was set while holding short of the runway for takeoff. Passengers and crew were removed and Maintenance took over the aircraft.

Narrative: Holding short of runway with parking brake set. When cleared for takeoff; I released the parking brake but the airplane would not move. The brakes wouldn't release. We did some troubleshooting in the cockpit and after numerous failed attempts to disengage the brakes we called Dispatch and [Maintenance]. [Maintenance] had us duplicate what we had already attempted to disengage the brakes but had no success. We notified ATC of our problem when it first happened and after calling [Maintenance] we informed ATC that we would be shutting down and waiting for a mechanic to come to the airplane. When the mechanic came; he was also unable to disengage the brakes and he told us that he would have to put the airplane on jacks in order to find the problem. We were in contact with station operations and ATC as to the next step; which was to bring air stairs and busses to deplane the passengers on the taxiway and return them to the terminal. The police and fire came to the plane then the busses and air stairs showed up. The passengers deplaned and the police and fire escorted them to the busses.Given the unusual circumstances of this event; I feel that all parties involved did a great job. We provided all the necessary food; water and information to the passengers during this event. We were able to secure another airplane and left a couple hours late.

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	1443955
Time
Date	201704
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	Parking Brake
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Type 675
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 9000 Flight Crew Type 3692
Events
Anomaly	Aircraft Equipment Problem Less Severe

B737 flight crew reported the parking brake would not release after it was set while holding short of the runway for takeoff. Passengers and crew were removed and maintenance took over the aircraft.