Narrative:

Flight normal all the way to phx right up to moments before touchdown. First officer (first officer) flying; captain monitoring. At approximately 50 feet above ground; master caution lights illuminated and were immediately canceled 3 or 4 times throughout the touchdown and landing rollout. Once stabilized at slower speed on runway I was able to look around and see the source of the problem. Both hydraulic B low pressure lights were flickering; quantity was decreasing through 20% and pressure erratic below 1;000 psi. Quantity and pressure then went to 0. First officer reported that thrust reversers were slow to deploy and auto-brakes did not engage as expected. Normal for this type of system failure but because we were unaware of the failure there was definitely a 'surprise factor' involved. Manual braking and reverse thrust slowed the aircraft and enabled runway exit. As we were clearing the runway; ATC told us to turn left on taxiway C along with some other instructions. Knowing that the aircraft brakes are on the failed hydraulic B system; I did not feel comfortable taxiing any more than necessary. I decided it would be most prudent to continue the same direction (right turn) off high speed taxiway B6 onto parallel taxiway bravo and stop the aircraft off the runway and remain clear of other exit taxiways. It took a bit of back and forth but we eventually communicated our predicament to ATC; safely stopped and arranged for a tow to the gate.

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Original NASA ASRS Text

Title: B737 Captain reported ground taxiway incursion due to hydraulic system B failure on landing.

Narrative: Flight normal all the way to PHX right up to moments before touchdown. First Officer (FO) flying; Captain monitoring. At approximately 50 feet above ground; master caution lights illuminated and were immediately canceled 3 or 4 times throughout the touchdown and landing rollout. Once stabilized at slower speed on runway I was able to look around and see the source of the problem. Both Hydraulic B Low Pressure lights were flickering; quantity was decreasing through 20% and pressure erratic below 1;000 PSI. Quantity and pressure then went to 0. FO reported that thrust reversers were slow to deploy and auto-brakes did not engage as expected. Normal for this type of system failure but because we were unaware of the failure there was definitely a 'surprise factor' involved. Manual braking and reverse thrust slowed the aircraft and enabled runway exit. As we were clearing the runway; ATC told us to turn left on Taxiway C along with some other instructions. Knowing that the aircraft brakes are on the failed Hydraulic B system; I did not feel comfortable taxiing any more than necessary. I decided it would be most prudent to continue the same direction (right turn) off high speed taxiway B6 onto parallel taxiway Bravo and stop the aircraft off the runway and remain clear of other exit taxiways. It took a bit of back and forth but we eventually communicated our predicament to ATC; safely stopped and arranged for a tow to the gate.

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.