B737 flight crew reported they were unable to pressurize due to both packs tripped.

Attributes
ACN	1395282
Time
Date	201610
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Pilot Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Type 6484
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 250 Flight Crew Type 5316
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

On climbout; both packs tripped. Accomplished appropriate check list. Both re- set. Then one then the other tripped again. Accomplished check list again. After few minutes both packs tripped again. Pressurization was erratic. We then decided to return to our departure airport. No need for the use of oxygen or mask deployment. Highest cabin altitude reached was 5;500.maintenance checked the aircraft system. We then departed with no further incident.

Original NASA ASRS Text

Title: B737 flight crew reported they were unable to pressurize due to both packs tripped.

Narrative: On climbout; both packs tripped. Accomplished appropriate check list. Both re- set. Then one then the other tripped again. Accomplished check list again. After few minutes both packs tripped again. Pressurization was erratic. We then decided to return to our departure airport. No need for the use of oxygen or mask deployment. Highest cabin altitude reached was 5;500.Maintenance checked the aircraft system. We then departed with no further incident.

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.