A Q400 captain reported high workload after takeoff and failure to open the pneumatic bleeds; result...

Narrative:

After [bleeds-off] takeoff while performing the after takeoff items; we received a clearance to 'resume the arrival'. We got this clearance just before I turned on the bleeds. I then reached across to program the first officer's FMS. I then made a mistake during the programming; and had to take a little more time to rectify the error. Once I had gotten that corrected; I reprogrammed my FMS. We then received another climb clearance; which I promptly put into the alerter. At this point we were about to enter the clouds and icing conditions; so I selected on the icing equipment. Needless to say; I never got the bleeds selected on; and apparently never finished the checklist. On descent at about 10;000 ft we received a cabin altitude warning light. We immediately realized the bleeds were off; and selected them on. We were already in the descent to 7;000 ft; and before we could complete the emergency checklist; the light extinguished.

Original NASA ASRS Text

Title: A Q400 Captain reported high workload after takeoff and failure to open the pneumatic bleeds; resulting in the aircraft's failure to pressurize. When bleeds were opened; normal operation resumed.

Narrative: After [bleeds-off] takeoff while performing the after takeoff items; we received a clearance to 'resume the arrival'. We got this clearance just before I turned on the bleeds. I then reached across to program the First Officer's FMS. I then made a mistake during the programming; and had to take a little more time to rectify the error. Once I had gotten that corrected; I reprogrammed my FMS. We then received another climb clearance; which I promptly put into the alerter. At this point we were about to enter the clouds and icing conditions; so I selected on the icing equipment. Needless to say; I never got the bleeds selected on; and apparently never finished the checklist. On descent at about 10;000 ft we received a cabin altitude warning light. We immediately realized the bleeds were off; and selected them on. We were already in the descent to 7;000 ft; and before we could complete the emergency checklist; the light extinguished.

Data retrieved from NASA's ASRS site as of July 2013 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	1020649
Time
Date	201207
Local Time Of Day	0001-0600
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Q400
Operating Under FAR Part	Part 121
Flight Phase	Climb Initial Climb
Flight Plan	IFR
Component
Aircraft Component	Pneumatic System
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Flying First Officer
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

A Q400 captain reported high workload after takeoff and failure to open the pneumatic bleeds; resulting in the aircraft's failure to pressurize. When bleeds were opened; normal operation resumed.