Dash 8-100
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Critical; Inflight Event / Encounter Other / Unknown
Flight Crew Returned To Departure Airport; General Maintenance Action; General Flight Cancelled / Delayed
Aircraft; Manuals
After gear retraction; the Captain noted that the Number 2 Hydraulic Quantity was low. We continued to climb out and requested a clearance to circle the airport so that we could run checklist. Note that the Preflight Inspection showed no signs of a hydraulic leak. Also; the checklist prior to takeoff; indicated that the hydraulic quantities were appropriate. The Captain; who was the pilot not flying; noted that the Number 2 Hydraulic Quantity was one quart; with no associated caution lights. Upon gear retraction; a hydraulic line in the Nose Wheel Well began leaking.We completed all checklist after takeoff and requested a right traffic pattern on Runway 34. Then; we ran the loss of Number 2 Hydraulic Quantity Emergency Checklist and stopped prior to the Alternate Gear Extension Checklist. We contacted Maintenance. We asked if we should do a Normal Gear Extension or the Alternate Extension. We were instructed to complete a Normal Gear Extension. We decided to transfer controls in the event that we lost all [hydraulic] quantity and had to complete an Alternate Gear Extension; which should be done from the right seat. Upon selecting Gear 'Down'; the gear came down normally; but the Number 2 Hydraulic Quantity went to .7. Two Caution lights illuminated: the Number 2 ISO Valve and Outboard Roll Spoilers. The Landing Gear Doors also remained open. We landed on Runway 34 due to favorable winds (Runway 9 had only 6;500 FT of usable runway). [Incident] unavoidable per Maintenance; the [Hydraulic] Flex Line was within its cycle limitation. Loss of Number 2 Hydraulic Quantity. Operated in degraded conditions. Air Turnback. Flight cancelled.
After gear retraction I; (pilot not flying); noticed the Number 2 Hydraulic Quantity was one quart with 3;000 PSI and no associated caution lights. We continued normally until completion of the After Takeoff Checklist. We then requested right traffic pattern over Runway 34 at 3;000 FT. I contacted Dispatch and Maintenance. We were instructed by Maintenance that a Normal Gear Extension was fine and an Alternate (Alt) Extension wasn't required. We talked to the Flight Attendant and passengers. I discussed with the First Officer the hydraulic services we may lose and the possibility of an Alternate Extension. We decided to transfer controls so I was pilot flying. Upon gear extension we received the Number 2 Isolation (Iso) Valve and Outboard Roll Spoiler Caution lights. The gear came down; three green [lights] and the gear doors stayed open. We discussed that we lost Nose Wheel Steering; [no] ability to recharge Emergency (E) Brake; Gear retraction; and Outboard Spoilers. Returned to ZZZ. We landed on Runway 34 due to favorable wind and Runway 9 was only 500 FT longer due to runway construction.
A Captain and First Officer return to a departure airport after noticing the Number 2 Hydraulic Quantity was down to one quart on their DHC-8-100 aircraft and no caution lights had illuminated. After Normal Gear Extension the Number 2 Hydraulic Quantity went to .7; Caution lights illuminated. Maintenance noticed a hydraulic flex line had failed in the Nose wheel well; even though the line was still within duty cycle limitations.