Q400 first officer reported loss of hydraulic system 1 fluid quantity resulted in a precautionary la...

Narrative:

During initial descent into ZZZ from ZZZ1; the #1 hydraulic iso vlv and inboard roll spoilers caution lights illuminated. We then began running the #1 hydraulic iso vlv east&a checklist while the captain assumed the radios. While running the checklist; the #1 hydraulic qty dropped down to 20% and slowly ran down to zero; but the hydraulic pressure remained adequate. We requested a hold with ATC and decided to request priority handling. When the caution lights extinguished; we then ran the #1 hydraulic qty low checklist in the east&a checklist. Once all checklists were completed and all parties were informed; we then proceeded to ZZZ to land. We opened up the flap power caution checklist in case our flaps did not extend. We made sure to configure early; in case the flaps did not deploy; and because the flaps were going to operate slower than usual. We were able to land without incident; and taxi to the gate with minimal normal breaking and the use of the emergency break. We had crash fire rescue and a tug standing by in case we needed any assistance. As stated in event narrative.

Original NASA ASRS Text

Title: Q400 First Officer reported loss of Hydraulic System 1 Fluid Quantity resulted in a precautionary landing.

Narrative: During initial descent into ZZZ from ZZZ1; the #1 HYD ISO VLV and Inboard Roll Spoilers caution lights illuminated. We then began running the #1 HYD ISO VLV E&A checklist while the Captain assumed the radios. While running the checklist; the #1 HYD QTY dropped down to 20% and slowly ran down to zero; but the HYD pressure remained adequate. We requested a hold with ATC and decided to request priority handling. When the caution lights extinguished; we then ran the #1 HYD QTY LOW Checklist in the E&A checklist. Once all checklists were completed and all parties were informed; we then proceeded to ZZZ to land. We opened up the Flap Power caution checklist in case our flaps did not extend. We made sure to configure early; in case the flaps did not deploy; and because the flaps were going to operate slower than usual. We were able to land without incident; and taxi to the gate with minimal normal breaking and the use of the emergency break. We had crash fire rescue and a tug standing by in case we needed any assistance. As stated in event narrative.

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	1756872
Time
Date	202008
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Q400
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Hydraulic System
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy

Q400 first officer reported loss of hydraulic system 1 fluid quantity resulted in a precautionary landing.