Narrative:

While enroute to mem we were cleared to descend via the tammy RNAV STAR; north transition. I read back the clearance and then the captain questioned ATC about the speed and altitude restrictions over tammy and rocab. ATC verified the fixes/altitudes/speeds on the arrival and we completed our briefing. Since the captain had already questioned ATC himself; I understood that he had heard the 'descend via' instruction and was complying. (The captain had not participated in any RNAV arrivals into mem before but we had gone over them the day before.)as I was about to question him; ATC came back and was asking what we were assigned. I responded that we were assigned the descend via tammy 4. She questioned repeatedly and I answered and then we were reassigned a heading. We continued into mem with no other complications and were asked to call ATC when we got on the ground. The call was placed and they just wanted to go over what had happened and were requesting further information since the RNAV arrivals have had problems.we should always confirm the 'descend via' read back. Also the RNAV's into mem plates are very small and jumbled. I think having the pull out pages and more to scale spacing would help greatly. I know I am constantly cross-checking with the FMS and plate when I fly the RNAV's because there are so many different options and routes crammed into the small page. Also; maybe hard altitudes [should be charted] instead of all the [above/below] variances. We were at an appropriate speed and altitude at tammy but with rocab only two miles away; I did not have time to correct the captain.

Google
 

Original NASA ASRS Text

Title: A CRJ-200 Flight Crew addressed their concerns about ATC phraseology and their aircraft's autoflight system's capability to cope with the more complex aspects of the TAMMY RNAV STAR to MEM.

Narrative: While enroute to MEM we were cleared to descend via the TAMMY RNAV STAR; North transition. I read back the clearance and then the Captain questioned ATC about the speed and altitude restrictions over TAMMY and ROCAB. ATC verified the fixes/altitudes/speeds on the arrival and we completed our briefing. Since the Captain had already questioned ATC himself; I understood that he had heard the 'descend via' instruction and was complying. (The Captain had not participated in any RNAV arrivals into MEM before but we had gone over them the day before.)As I was about to question him; ATC came back and was asking what we were assigned. I responded that we were assigned the descend via Tammy 4. She questioned repeatedly and I answered and then we were reassigned a heading. We continued into MEM with no other complications and were asked to call ATC when we got on the ground. The call was placed and they just wanted to go over what had happened and were requesting further information since the RNAV arrivals have had problems.We should always confirm the 'descend via' read back. Also the RNAV's into MEM plates are very small and jumbled. I think having the pull out pages and more to scale spacing would help greatly. I know I am constantly cross-checking with the FMS and plate when I fly the RNAV's because there are so many different options and routes crammed into the small page. Also; maybe hard altitudes [should be charted] instead of all the [above/below] variances. We were at an appropriate speed and altitude at TAMMY but with ROCAB only two miles away; I did not have time to correct the Captain.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.