B717-200 first officer reported loss of right hydraulic system fluid; resulting in the crew declarin...

Narrative:

[On a previous flight we] had a hydraulic right qty lo alert. The next day; we operated the same aircraft. The aircraft hydraulics had been serviced and the logbook was signed off by maintenance. After we departed; at about FL180; the hydraulic quantity was noted as decreasing below 9 units. Approximately 40 minutes into the flight; the hydraulic quantity was decreasing to below 7 units. Contact was made with dispatch and maintenance via commercial radio. Maintenance recommended that we land in [a nearby suitable airport]. As we approached [destination] the hydraulic qty lo alert illuminated; and an emergency was declared the QRH was run; and checklists completed. We landed uneventfully.after arriving at the gate I had a chance to talk with maintenance and see what caused the loss of hydraulic fluid. The right main gear hydraulic actuator line for retracting the gear was leaking and seeping through the line. This would not have been noticed with the gear extended and difficult to identify on a walk around preflight inspection.

Original NASA ASRS Text

Title: B717-200 First Officer reported loss of right hydraulic system fluid; resulting in the crew declaring an emergency and diverting to the nearest suitable airport. First Officer mentioned the system had been serviced by Maintenance the day before following a loss of fluid.

Narrative: [On a previous flight we] had a HYD R QTY Lo alert. The next day; we operated the same aircraft. The aircraft hydraulics had been serviced and the logbook was signed off by Maintenance. After we departed; at about FL180; the hydraulic quantity was noted as decreasing below 9 units. Approximately 40 minutes into the flight; the hydraulic quantity was decreasing to below 7 units. Contact was made with Dispatch and Maintenance via Commercial Radio. Maintenance recommended that we land in [a nearby suitable airport]. As we approached [destination] the HYD QTY LO alert illuminated; and an emergency was declared the QRH was run; and checklists completed. We landed uneventfully.After arriving at the gate I had a chance to talk with Maintenance and see what caused the loss of hydraulic fluid. The right main gear hydraulic actuator line for retracting the gear was leaking and seeping through the line. This would not have been noticed with the gear extended and difficult to identify on a walk around preflight inspection.

Data retrieved from NASA's ASRS site as of July 2013 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	1025218
Time
Date	201207
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	B717 (Formerly MD-95)
Operating Under FAR Part	Part 121
Flight Phase	Climb
Component
Aircraft Component	Hydraulic Main System
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

B717-200 first officer reported loss of right hydraulic system fluid; resulting in the crew declaring an emergency and diverting to the nearest suitable airport. First officer mentioned the system had been serviced by maintenance the day before following a loss of fluid.