B757-200
Situational Awareness; Training / Qualification; Troubleshooting
Aircraft Equipment Problem Less Severe
Flight Crew Landed in Emergency Condition; Flight Crew FLC complied w / Automation / Advisory; General Declared Emergency; General Maintenance Action
Aircraft
During Descent and going through FL220; EICAS showed a R HYD QTY and also RSVR light on the overhead panel.  Status page of engine showed an 'RF' on the right system and also a QTY indication between .04 and .09. QRH was checked and landed the aircraft without incident.  Emergency was declared.
The Reporter stated that all quantity indications returned to normal after landing and maintenance determined that the hydraulic quantity sensor failed.
A B757 EICAS alerted R HYD QTY; the RSVR light illuminated and the quantity indicating 0.09 so the QRH procedure was completed; an emergency declared followed by a normal landing after which all quantity indications returned to normal.