Large Transport
Flight Crew Last 90 Days 170; Flight Crew Type 5500
Situational Awareness; Confusion; Communication Breakdown; Distraction
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure
While 'descending via' on EMZOH2 into OAK; ATC vectored us off arrival and assigned various speed; heading; and altitudes.  Altitude assignments; not crossing restrictions; were challenging in icing conditions while complying with the MEL for a wired open engine anti-ice valve that requires a minimum of 60 percent N1 on that engine.  Again; they were all complied with and ATC said nothing. After quite a while and while level at 7;000 feet; ATC issued us a 'direct to' LOGHN clearance and 'resume the arrival.'  No altitude revision was issued; including 'descend via.'  A Controller or frequency change occurred and at approximately three miles from LOGHN; the new Controller asked if we were 'descending via' the arrival.  We replied that we were rejoining the arrival; but our last clearance was to 'maintain' 7;000 feet.  He seemed confused and issued a heading and a decent.  Nothing else was mentioned and there was no deviation at all. We were at 7;000 feet at LOGHN and the cross at that fix; had we been cleared to descend via; was 6;000A; above 6;000 feet.  I guess this report is just a precaution against any unknown issue that ATC may have.  I feel that it was a non-event; however.
Aircraft had an MEL for anti-ice valve wired open; had to maintain 60 percent N1 on it while in icing conditions.  While descending on the EMZOH2 Arrival into OAK; we were given a heading off the arrival and told to stop the descent at 7;000 feet.  We were then given direct LOHGN and to resume the arrival.  Then we were switched to final Approach Control. At LOHGN at 7; 000 feet; ATC wanted to know our altitude.  We responded with 7;000 feet assigned.  He said no; we should be descending on the arrival.  He then gave us an altitude to descend to.  We joined final and landed in OAK.
Pilots reported of being taken off an arrival; vectored; and given an altitude to maintain. ATC then gave the crew a direct to and maintain an altitude. The crew was issued a frequency change and the new controller wanted to know why they were not descending on the arrival. The crew replied they were given direct to a point and to maintain an altitude. ATC was confused.