Narrative:

We were in cruise on our filed route. The master caution light came on and I told the captain to identify the problem. It was a number 1 hydraulic iso vlv light. We both looked down at the hydraulic panel and noticed the number 1 hydraulic quantity gauge was showing approximately 1. I asked him to pull out the checklist and run the number 1 hydraulic system failure checklist. We determined that we had no quantity and no pressure. We ran the checklist. I continued to fly the airplane and run the radios while the captain went off to call dispatch on the satcom. After talking to dispatch; it was decided that we were not going to continue to our destination; but instead were going to divert where they had a 10;001 ft runway where we could safely land without flaps and normal brakes that were lost with the hydraulic system failure. I continued to fly the aircraft and [notified ATC]; telling them our souls on board; amount of fuel on board; the nature of our [situation]; and that we wanted direct to the airport and [assistance] standing by. The captain was still off the radio and called the flight attendant and notified the passengers of our situation. Center started us on a slow decent out of 16;000 ft and I pulled back the power to stay under 200 kts as is required by some of the new caution lights that began to appear on the caution panel (rudder full press). Captain came back after briefing the flight attendant and passengers and we transferred flight controls to him. We ran through the checklist a second time to make sure everything was done correctly and we were fully aware of all the systems we had lost due to the failure. We discussed the flapless landing and the new ref and approach speeds that were required by the situation. We landed at 127 kts and captain put the plane into full reverse to stop it. He put the parking brake on and we had vehicles enter the runway and check us for fire or damage; nothing was noted by them.master caution light illuminated and number 1 hydraulic iso vlv light illuminated on the caution panel. Alerted us to look down to the hydraulic panel. Number 1 hydraulic system failure due to loss of hydraulic fluid. Maintenance personnel would know exact cause.

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Original NASA ASRS Text

Title: During flight; in a De Havilland DHC-8-102; Number 1 Hydraulic System Failed due to loss of hydraulic fluid.

Narrative: We were in cruise on our filed route. The Master Caution light came on and I told the Captain to identify the problem. It was a Number 1 HYD ISO VLV light. We both looked down at the Hydraulic panel and noticed the Number 1 Hydraulic Quantity gauge was showing approximately 1. I asked him to pull out the checklist and run the Number 1 Hydraulic system failure checklist. We determined that we had no quantity and no pressure. We ran the checklist. I continued to fly the airplane and run the radios while the Captain went off to call Dispatch on the SatCom. After talking to Dispatch; it was decided that we were not going to continue to our destination; but instead were going to divert where they had a 10;001 ft runway where we could safely land without flaps and normal brakes that were lost with the hydraulic system failure. I continued to fly the aircraft and [notified ATC]; telling them our souls on board; amount of fuel on board; the nature of our [situation]; and that we wanted direct to the airport and [assistance] standing by. The Captain was still off the radio and called the Flight Attendant and notified the passengers of our situation. Center started us on a slow decent out of 16;000 ft and I pulled back the power to stay under 200 kts as is required by some of the new caution lights that began to appear on the caution panel (Rudder Full Press). Captain came back after briefing the flight attendant and passengers and we transferred flight controls to him. We ran through the checklist a second time to make sure everything was done correctly and we were fully aware of all the systems we had lost due to the failure. We discussed the flapless landing and the new Ref and approach speeds that were required by the situation. We landed at 127 kts and Captain put the plane into full reverse to stop it. He put the Parking Brake on and we had vehicles enter the runway and check us for fire or damage; nothing was noted by them.Master Caution light illuminated and Number 1 HYD ISO VLV light illuminated on the Caution Panel. Alerted us to look down to the Hydraulic Panel. Number 1 Hydraulic System Failure due to loss of hydraulic fluid. Maintenance personnel would know exact cause.

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.