A320 flight crew reported receiving a TA after the autopilot overshot a crossing restriction on desc...

Attributes
ACN	1350803
Time
Date	201604
Local Time Of Day	0601-1200
Place
Locale Reference	PHX.Airport
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR HYDRR1
Flight Plan	IFR
Aircraft 2
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Conflict Airborne Conflict Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy

Narrative:

Received two tas; reduced range on navigation display; visually identified first TA off aircraft right side and visually identified aircraft behind and below left side of aircraft. We both noticed that automatic pilot did not honor the 9000 ft restriction at chavo intersection; as PF; I intervened at 8700 ft and climbed back to 9000 ft. After landing; we were notified of a possible deviation.the aircraft did not honor the 9000 ft altitude restriction at chavo combined with two tas resulted in my having to intervene at 8700 ft and climb back to 9000 ft.

Original NASA ASRS Text

Title: A320 flight crew reported receiving a TA after the autopilot overshot a crossing restriction on descent into PHX.

Narrative: Received two TAs; reduced range on NAV Display; visually identified first TA off aircraft right side and visually identified aircraft behind and below left side of aircraft. We both noticed that automatic pilot did not honor the 9000 ft restriction at CHAVO intersection; as PF; I intervened at 8700 ft and climbed back to 9000 ft. After landing; we were notified of a possible deviation.The aircraft did not honor the 9000 ft altitude restriction at CHAVO combined with two TAs resulted in my having to intervene at 8700 ft and climb back to 9000 ft.

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.

A320 flight crew reported receiving a TA after the autopilot overshot a crossing restriction on descent into phx.