A320 flight crew reports missing the crossing restriction at trtle during descent on the baset 3 to ...

Narrative:

Crossed konzl at 17;000 ft. ATC cleared us to descend via the baset 3 arrival and expect ILS 7R; we had briefed and programmed ILS 6L in FMS. I was pilot flying and dialed in 10;000 ft in the altitude window and pushed altitude; and then changed the runway to 7R in FMS. We were briefing the new runway when ATC said to maintain 14;000 ft as we missed our crossing restriction at trtle and he said he didn't want us to go below his airspace. We were at 14;500 ft at that time. No other aircraft were within 15 miles of us. We continued our descent to 14;000 ft and that was the end of the altitude deviation. I think the crossing restriction dropped out when I changed runways or went into open descent when the new runway was inserted and I didn't notice it. Then we were briefing the new approach we had just been assigned when we flew through the altitude. Task saturation and unfamiliarity with landing on the 6's and 7's in lax as we almost always land on 24's and 25's contributed to this deviation.

Original NASA ASRS Text

Title: A320 flight crew reports missing the crossing restriction at TRTLE during descent on the BASET 3 to LAX. The aircraft went into open descent while entering an ATC assigned runway change into the FMGC and was not detected by the flight crew.

Narrative: Crossed KONZL at 17;000 FT. ATC cleared us to descend via the BASET 3 Arrival and expect ILS 7R; we had briefed and programmed ILS 6L in FMS. I was pilot flying and dialed in 10;000 FT in the altitude window and pushed altitude; and then changed the runway to 7R in FMS. We were briefing the new runway when ATC said to maintain 14;000 FT as we missed our crossing restriction at TRTLE and he said he didn't want us to go below his airspace. We were at 14;500 FT at that time. No other aircraft were within 15 miles of us. We continued our descent to 14;000 FT and that was the end of the altitude deviation. I think the crossing restriction dropped out when I changed runways or went into open descent when the new runway was inserted and I didn't notice it. Then we were briefing the new approach we had just been assigned when we flew through the altitude. Task saturation and unfamiliarity with landing on the 6's and 7's in LAX as we almost always land on 24's and 25's contributed to this deviation.

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	984117
Time
Date	201112
Local Time Of Day	1801-2400
Place
Locale Reference	SCT.TRACON
State Reference	CA
Aircraft 1
Make Model Name	A320
Operating Under FAR Part	Part 121
Flight Phase	Descent
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance

A320 flight crew reports missing the crossing restriction at trtle during descent on the baset 3 to lax. The aircraft went into open descent while entering an ATC assigned runway change into the FMGC and was not detected by the flight crew.