An A321 captain and the ZDV controller involved both describe an altitude deviation while the A321 c...

Attributes
ACN	1063027
Time
Date	201301
Local Time Of Day	1201-1800
Place
Locale Reference	ZDV.ARTCC
State Reference	CO
Aircraft 1
Make Model Name	A321
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Airway JAGGR1
Flight Plan	IFR
Component
Aircraft Component	MCP
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Airspace Violation All Types Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

The A321 checked on at FL300 and was flying the JAGGR1 arrival. Cheyenne MOA/atcaa was active FL290 and below. Descending via the JAGGR1 ensures separation with cys atcaa by using altitude (requires aircraft to be FL300-340 after clear of cys). I gave the A321 a clearance to descend via the JAGGR1 arrival. He was vertically above cys but laterally within the confines. I noticed him start to descend while still in the lateral confines (I noticed at FL296) of cys by approximately 4 miles. I amended his altitude to FL290 and explained to him that he started his descent too early; as he was required to cross jaggr waypoint between FL300-340. Pilots [need] to understand fully the RNAV arrivals and clearances. Also; I am no longer going to issue the descend via clearance while the aircraft are laterally within the confines of cys atcaa anymore even though it ensures separation. I will wait until they are clear so if they start down early by mistake they won't bust military space.

Original NASA ASRS Text

Title: An A321 Captain and the ZDV Controller involved both describe an altitude deviation while the A321 crew is attempting to comply with the altitude restrictions of the JAGGR 1 RNAV arrival into DEN. The aircraft had responded to an MCP input in an unexpected way.

Narrative: The A321 checked on at FL300 and was flying the JAGGR1 arrival. Cheyenne MOA/ATCAA was active FL290 and below. Descending via the JAGGR1 ensures separation with CYS ATCAA by using altitude (requires aircraft to be FL300-340 after clear of CYS). I gave the A321 a clearance to descend via the JAGGR1 arrival. He was vertically above CYS but laterally within the confines. I noticed him start to descend while still in the lateral confines (I noticed at FL296) of CYS by approximately 4 miles. I amended his altitude to FL290 and explained to him that he started his descent too early; as he was required to cross JAGGR waypoint between FL300-340. Pilots [need] to understand fully the RNAV arrivals and clearances. Also; I am no longer going to issue the descend via clearance while the aircraft are laterally within the confines of CYS ATCAA anymore even though it ensures separation. I will wait until they are clear so if they start down early by mistake they won't bust military space.

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.

An A321 captain and the ZDV controller involved both describe an altitude deviation while the A321 crew is attempting to comply with the altitude restrictions of the jaggr 1 RNAV arrival into den. The aircraft had responded to an MCP input in an unexpected way.