Twin Bonanza 50
Air Traffic Control Fully Certified
Situational Awareness; Training / Qualification
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Airspace Structure; Chart Or Publication; Human Factors; Weather
Aircraft X checked onto my frequency from Seattle Approach and was looking for the lowest altitude possible for icing. At first I told him I could only get him down to 8;400 feet; which was the Minimum Enroute Altitude (MEA) on V2. My Minimum IFR Altitude was lower in the area but I would have lost radar contact with him and did not want him to be on vectors. Aircraft X advised me that he was GPS equipped and requesting the GPS MEA of 7;700 feet which I did not even realize was an option on the airway.I gave it a quick glance to confirm and I issued him a descent to 7;700 feet. He did indeed go non-radar for a portion and reported BEEZR at which point I had him back an re-identified him. At that point it was questioned by my Assist controller about the MEA after BEEZR. I quickly realized the GPS MEA was no longer valid and needed him up to 8;000 feet by BEEZR. I issued him a climb to regain compliance with the MEA on the airway. It might just be me; but since I learned how to read maps and charts and there was a few moments of panic as myself and my Assist were trying to determine what all the numbers were. We were confused by the MEA and also the Minimum Obstruction Clearance Altitude (MOCA); about what we could use and how to apply it. At least in our area; we don't do very much low altitude work and getting refreshed on what everything means again would be beneficial. I will definitely take the time to re-learn on my own. With more and more younger controllers coming in that have never used it at all before; it might be good to either clean up our maps if there are numbers that aren't even applicable or to have some of that included in our annual refresher.
A Center Controller was not familiar with the lowest altitudes he could approve for an aircraft experiencing icing and allowed the aircraft to fly below their Minimum Vectoring Altitude.