EMB ERJ 140 ER/LR
Flight Crew Air Transport Pilot (ATP)
Human-Machine Interface; Confusion; Communication Breakdown; Situational Awareness
ATC Issue All Types; Deviation - Altitude Crossing Restriction Not Met; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Flight Crew Requested ATC Assistance / Clarification
Chart Or Publication; Human Factors; Procedure
We were cleared to cross GUMMA at FL230. Upon reaching GUMMA we were cleared to descend via the RYYMN RNAV STAR. The layout on the STAR plate is very confusing. So I was looking through our course trying to find an altitude to set and came up with 4;000 feet. I started descending and my First Officer asked if we were cleared to descend. I said 'yes; [we're] cleared via the STAR.' So I decided to ask ATC what altitude they wanted and [whether] we were cleared to descend. He said 'yes; you are cleared to descend via the STAR.' I again asked what altitude they wanted and he said 'I don't know the altitude just descend via the STAR.' So we had slowed our descent and missed [RYYMN] between FL190 and 11;000 feet MSL by around a thousand feet. The rest was uneventful. The event occurred because of the horrible way this STAR is set up and worded. And the fact that ATC was of no help at all. There was not a lot of traffic around. We did not understand why this guy couldn't help us out. Also; my First Officer was questioning the clearance which made me question it also. By that time we were just too high.
The flight crew of an EMB-140 was confused by the formatting of the RYYMN RNAV STAR to BNA; when 'cleared via' the STAR they were unable to determine what altitude should be selected in the altitude alert window; an appropriate setting for which is required to allow VNAV functions to be performed by the autoflight system.