Narrative:

While commencing the Eagul6 arrival into phx after experiencing heavy weather; moderate turbulence; multiple deviations; changed altitude crossing restrictions; and a late top of descent clearance; we were cleared to descend via the STAR. As the pilot flying I selected 'managed descent' and ensured the FMA agreed with my input. As we broke out of the weather and turbulence in the vicinity of homer intersection; I was somewhat relieved and newly complacent about our; now; easier path to the airport. The captain and I had a short discussion about the fact that we had not been handed over to phx approach yet; which seemed to be late. Our focus was somewhat shifted to that issue and may have distracted us from the fact that the aircraft's vertical model had somehow shifted into 'open descent' from 'managed descent.' I realized this when the floor of the crossing restriction window was not be honored at esdee intersection. I then intervened by disconnecting the autopilot and leveling off at 8;100 feet. The captain and I noticed at the time that the descent mode no longer agreed with the previous selection. The captain agreed that he verified 'managed descent' was previously verified by him on the FMA at the time the descent via clearance was received.in retrospect; neither of us are certain that the 'at or above' at vnnom intersection was honored due to the missed mode change during our multiple flight deck distractions (weather; deviations; late handoff; etc.) from the top of descent point. As a result; I can only endeavor to be less complacent; despite flight deck distractions; when arriving at a familiar airport via a commonly used arrival to ensure that all restrictions are actually being met on the profile.

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Original NASA ASRS Text

Title: A320 First Officer reported becoming distracted by weather challenges and did not notice the autopilot had switched from managed descent to open descent.

Narrative: While commencing the Eagul6 arrival into PHX after experiencing heavy weather; moderate turbulence; multiple deviations; changed altitude crossing restrictions; and a late top of descent clearance; we were cleared to descend via the STAR. As the pilot flying I selected 'managed descent' and ensured the FMA agreed with my input. As we broke out of the weather and turbulence in the vicinity of HOMER intersection; I was somewhat relieved and newly complacent about our; now; easier path to the airport. The captain and I had a short discussion about the fact that we had not been handed over to PHX approach yet; which seemed to be late. Our focus was somewhat shifted to that issue and may have distracted us from the fact that the aircraft's vertical model had somehow shifted into 'open descent' from 'managed descent.' I realized this when the floor of the crossing restriction window was not be honored at ESDEE intersection. I then intervened by disconnecting the Autopilot and leveling off at 8;100 feet. The Captain and I noticed at the time that the descent mode no longer agreed with the previous selection. The Captain agreed that he verified 'managed descent' was previously verified by him on the FMA at the time the descent via clearance was received.In retrospect; neither of us are certain that the 'At or above' at VNNOM intersection was honored due to the missed mode change during our multiple flight deck distractions (weather; deviations; late handoff; etc.) from the top of descent point. As a result; I can only endeavor to be less complacent; despite flight deck distractions; when arriving at a familiar airport via a commonly used arrival to ensure that all restrictions are actually being met on the profile.

Data retrieved from NASA's ASRS site 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.