Communication Breakdown
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Wake Vortex Encounter
Air Traffic Control Issued New Clearance
Environment - Non Weather Related; Human Factors; Procedure
We were filed and cleared via the SITTH 2 arrival into Atlanta. TCAS was deferred per MEL. Enroute ATIS for ATL was obtained and stated PRM approaches landing east were in use. After contacting Dispatch and consulting the Flight Manual; it was determined PRM approaches could not be conducted due to TCAS inoperative. ATL Approach Control was notified on initial contact and we were told to expect runway 9R. Approach then cleared us to descend via the SITTH 2 arrival. Shortly after; we received a runway change and were assigned runway 8L for landing and accomplished the required runway change items. Approach Control then cleared us direct GAASS (fix on SITTH 2 for 8L) and told us to descend and maintain 8000'. Both pilots acknowledged instruction and verified descent to 8000'. Approach Control handed us off to a different Approach frequency. Upon checking in on the new frequency; we were immediately told to stop our descent and climb to 11;000' and fly an assigned heading. We read back and complied with these instructions. We then explained to the Controller that the previous Controller had cleared us to descend to 8;000'. The Controller then cleared us direct KLOWD on the SITTH arrival. During downwind; we subsequently encountered moderate wake turbulence resulting in 40 degrees of bank left and right. ATC was notified of this event and no further turbulence was encountered. The arrival and approach were also completed with no further events. TCAS inoperative prevented PRM approaches and required ATC modified clearances; which eventually resulted in ATC miscommunication. Wake turbulence was an unrelated event to the TCAS inoperative; but resulted in an [upset situation]. The MEL for TCAS does not indicate PRM approaches may be affected. Additionally; neither the approach plates nor PRM notice to all users page indicate TCAS is required for PRM approaches. Only after consulting Dispatch and the FOM were we able to determine that we could not conduct a PRM approach without TCAS. We suggest a note be added to the MEL that indicates PRM approaches are not authorized per the Flight Manual.
CRJ-200 First Officer reported a clearance misunderstanding which resulted in an altitude overshoot during arrival into ATL.