B737 flight crew reported diverting to an alternate airport after experiencing loss of the B hydraul...

Attributes
ACN	1443909
Time
Date	201704
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	Mixed
Light	Dawn
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Hydraulic Main System
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 201
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 209
Events
Anomaly	Aircraft Equipment Problem Less Severe

Narrative:

At cruise; the B low pressure light illuminated. The QRH for B low pressure light was accomplished. The B pressure and quantity remained normal. We discussed the low weather at our destination and the possibility of losing the B electric pump next with subsequent total loss of B hydraulics. Using the ipad we reviewed the best weather options for a total loss of the B system with a missed approach with the lights remaining on. As the flight continued; the B quantity and pressure did reduce to zero with no B electric light illumination. We decided to go with the divert plan that was previously just a passing thought. The divert was pretty quick and only one ACARS message to dispatch was made. The center gave us vectors for descent; the loss of B hydraulics QRH was accomplished. The landing was about 700 pounds overweight but uneventful. The fire department cleared us into the gate.

Original NASA ASRS Text

Title: B737 flight crew reported diverting to an alternate airport after experiencing loss of the B hydraulic system.

Narrative: At cruise; the B low pressure light illuminated. The QRH for B Low Pressure light was accomplished. The B pressure and quantity remained normal. We discussed the low weather at our destination and the possibility of losing the B electric pump next with subsequent total loss of B hydraulics. Using the iPad we reviewed the best weather options for a total loss of the B system with a missed approach with the lights remaining on. As the flight continued; the B quantity and pressure did reduce to zero with no B electric light illumination. We decided to go with the divert plan that was previously just a passing thought. The divert was pretty quick and only one ACARS message to Dispatch was made. The Center gave us vectors for descent; the Loss of B Hydraulics QRH was accomplished. The landing was about 700 pounds overweight but uneventful. The Fire Department cleared us into 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.