During the B1900 maintenance first flight run up the dump valve was mistakenly left on. After takeof...

Narrative:

My first officer and I accepted a plane that had been used by maintenance earlier that day to perform the first flight of the day run up. We did not realize it at the time but maintenance had left the dump valve on from their run up. As it is not part of the run up SOP to leave the dump valve on; we were later confused at it being on. As it is not part of any flows; checklists; or even emergency procedures (for cabin decompression) to check the valve; I did not check it until it sparked in my brain on final approach. By that time we had already called air return to dispatch and did not think it wise to cancel my landing and just continue on. There should be at least one checklist/ flow checking the dump valve. The emergency checklist for cabin decompression should reference it.

Original NASA ASRS Text

Title: During the B1900 maintenance first flight run up the Dump Valve was mistakenly left ON. After takeoff when the cabin would not pressurize; the flight crew returned to the departure airport and just before landing realized the Valve was ON but its position is not referenced in any checklist or flow.

Narrative: My First Officer and I accepted a plane that had been used by Maintenance earlier that day to perform the first flight of the day run up. We did not realize it at the time but Maintenance had left the Dump Valve ON from their run up. As it is not part of the run up SOP to leave the Dump Valve ON; we were later confused at it being ON. As it is not part of any Flows; Checklists; or even Emergency procedures (for cabin decompression) to check the valve; I did not check it until it sparked in my brain on final approach. By that time we had already called air return to Dispatch and did not think it wise to cancel my landing and just continue on. There should be at least one checklist/ flow checking the dump valve. The emergency checklist for cabin decompression should reference it.

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	1201727
Time
Date	201409
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	Beech 1900
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Pressurization System
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Commercial
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Commercial
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy

During the B1900 maintenance first flight run up the dump valve was mistakenly left on. After takeoff when the cabin would not pressurize; the flight crew returned to the departure airport and just before landing realized the valve was on but its position is not referenced in any checklist or flow.