B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 223; Flight Crew Type 10000
Communication Breakdown
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Requested ATC Assistance / Clarification
Procedure
While attempting to fly the RNAV RNP to Runway 13C; Approach Control vectored us toward the IAF but never clear us to the IAF. The phraseology used was 'intercept the approach course; maintain 180 KTS'. At this point; we were still restricted to 4;000 and not cleared the approach. Pilot not flying queried ATC asking; 'Are we cleared the RNAV RNP 13C approach?' ATC stated that we were cleared the RNAV RNP 13C approach. ATC should have cleared us initially to the IAF with subsequent clearance for the approach. Instead; we received confusing instructions and a speed restriction which was counter to the speeds directed in the RNP system. We missed the 2;500 altitude restriction because of the confusion of the ATC instruction. Unfortunately; we see Approach Control too often attempt to use the RNP approaches but use improper terminology; add additional non-standard altitude and speed instructions overlapping the directives of the published RNP approaches. These approaches do not work if ATC insists on overriding the details of the approaches.
A B737-700 flight crew took exception to the phraseology utilized by Approach Control when clearing their flight to intercept and fly the RNAV (GPS) Z Runway 13C approach to MDW.