Q400
Flight Crew Air Transport Pilot (ATP)
Troubleshooting; Workload; Distraction; Time Pressure
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification; General Maintenance Action
Aircraft; Chart Or Publication; Procedure
After being cleared for a visual approach to Runway 7; the ROLL SPLR INBD HYD and #1 HYD ISO VLV caution lights illuminated intermittently.  I referenced the ROLL SPLR INBD HYD checklist while the First Officer (FO) continued to set up for the approach.  Hydraulic pressures were normal.  I completed the checklist; just as the FO called for flaps and gear for landing.  We configured normally and landed the aircraft; but did not have normal braking available after landing.  Did not have any trouble slowing and stopping the aircraft with props and parking brake.  Nosewheel steering was still operable; so we cleared the runway; shutdown; and called for a tow to the gate.After landing we realized that we hadn't completed the #1 HYD ISO VLV checklist prior to landing.  That checklist would have alerted us to the loss of normal braking prior to landing; which would have been nice to know; and would have motivated us to declare an emergency; which we hadn't done.I had originally intended to address both caution lights; and chose to do the ROLL SPLR INBD HYD checklist first.  I should have asked the FO to delay the approach so we would have had more time to assess the problem; (which; it turns out; was a leak in the #1 hydraulic system) and complete all appropriate checklists.  By the time I had completed the ROLL SPLR INBD HYD checklist; it was time to configure for landing; which completely distracted me from my initial intention of addressing the #1 HYD ISO VLV checklist.  In reviewing the checklist after landing; we could see that the only difference it would have made is that we would have been alerted to the loss of normal braking beforehand; and could have declared an emergency prior to landing. So I would say that task saturation would be a contributing cause to our not addressing the #1 HYD ISO VLV checklist prior to landing.
A Q400 ROLL SPLR INBD HYD and #1 HYD ISO VLV caution lights illuminated intermittently so the QRH was partially completed prior to landing. After landing with no brakes or nose wheel steering; the crew realized they had not completed the checklists which would have alerted a hydraulic system leak.