A319 flight crew experiences an FMGC anomaly during descent on the kooly 3 RNAV arrival to phx; resu...

Narrative:

We were cleared to descend on the kooly 3 arrival runway 25L into phoenix. The aircraft was in managed descent mode and had been on speed and making all altitude restrictions. We had just been switched from abq center to phoenix approach. We had descended through 10;000 ft and were at 250 KTS. I was setting the phx approach frequency for the first officer; but I could not get .65 to display; only .75 or .55. We were both distracted by number 1 radio not displaying the .6 for about 45 seconds or so. When I looked at the aircraft profile; I saw that we had passed the deceleration point and the FMGC was commanding a speed reduction to approach speed. I pulled the speed knob to stop the aircraft form slowing; but I noticed the aircraft was actually accelerating through 280 KTS. I saw that the aircraft had gone into vertical speed and was descending at 3;600 FPM. I turned off the autopilot and stopped the descent at 7;100 ft and realized we were below the 8;000 ft altitude restriction at pukre. I climbed up to 8;000 ft and slowed the aircraft to 210 KTS. We contacted phx approach and the controller did not question our altitude; but did say to slow to 210 KTS; which we had already done. There had been no changes to the mcdu or the FCU. I have no idea why the aircraft went into vertical speed. If I had not been distracted by the radio display; I may have been able to stop the aircraft form going into vertical speed or at least not allowed the aircraft to continue to descend in vertical speed.

Original NASA ASRS Text

Title: A319 flight crew experiences an FMGC anomaly during descent on the KOOLY 3 RNAV arrival to PHX; resulting in descent below profile and speed above 280 KTS at 7;400 FT.

Narrative: We were cleared to descend on the KOOLY 3 arrival Runway 25L into Phoenix. The aircraft was in managed descent mode and had been on speed and making all altitude restrictions. We had just been switched from ABQ Center to Phoenix Approach. We had descended through 10;000 FT and were at 250 KTS. I was setting the PHX Approach frequency for the First Officer; but I could not get .65 to display; only .75 or .55. We were both distracted by number 1 radio not displaying the .6 for about 45 seconds or so. When I looked at the aircraft profile; I saw that we had passed the deceleration point and the FMGC was commanding a speed reduction to approach speed. I pulled the speed knob to stop the aircraft form slowing; but I noticed the aircraft was actually accelerating through 280 KTS. I saw that the aircraft had gone into vertical speed and was descending at 3;600 FPM. I turned off the autopilot and stopped the descent at 7;100 FT and realized we were below the 8;000 FT altitude restriction at PUKRE. I climbed up to 8;000 FT and slowed the aircraft to 210 KTS. We contacted PHX Approach and the Controller did not question our altitude; but did say to slow to 210 KTS; which we had already done. There had been no changes to the MCDU or the FCU. I have no idea why the aircraft went into vertical speed. If I had not been distracted by the radio display; I may have been able to stop the aircraft form going into vertical speed or at least not allowed the aircraft to continue to descend in vertical speed.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	967232
Time
Date	201108
Local Time Of Day	1201-1800
Place
Locale Reference	P50.TRACON
State Reference	AZ
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR KOOLY 3
Flight Plan	IFR
Component
Aircraft Component	FMS/FMC
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Deviation - Speed All Types

A319 flight crew experiences an FMGC anomaly during descent on the kooly 3 RNAV arrival to phx; resulting in descent below profile and speed above 280 KTS at 7;400 ft.