A321 flight crew reported overshooting a crossing restriction on the TYSSN3 arrival to las; with a w...

Attributes
ACN	1144391
Time
Date	201401
Local Time Of Day	0601-1200
Place
Locale Reference	LAS.Airport
State Reference	NV
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	A321
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR TYSSN
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	Descent
Person 1
Function	Pilot Not Flying First Officer
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Deviation - Altitude Crossing Restriction Not Met Deviation - Altitude Overshoot Deviation - Procedural Published Material / Policy Deviation - Track / Heading All Types Inflight Event / Encounter Wake Vortex Encounter

Narrative:

We were descending on the TYSSN3 arrival into las vegas. The kaddy intersection has a crossing restriction of 12;000 ft and 250 KTS. The automation was used and we were meeting all altitude crossings accordingly. Prior to reaching kaddy we began picking up moderate wake turbulence from the preceding aircraft. The captain (pilot flying) overrode the aircraft and shallowed the descent and it was now in a non-managed configuration. Also the aircraft was put into heading for maybe 5 seconds and he rearmed the navigation. The kaddy fix showed magenta and we were clearly going to make the restriction no problem.I was watching the descent and was waiting for it to level at the alt constraint of 12;000 ft before continuing down after kaddy. What happened is it went below 12;000 ft; I said to the captain to watch his altitude; kaddy has a 12;000 ft restriction. At this time we were at 11;600 ft and ATC gave us direct to prino essentially deleting the kaddy crossing. ATC never said anything about going below 12;000 ft but we clearly descended early. We talked about what happened and realized the aircraft was not put back into managed descent so it didn't honor the constraint. We needed to make sure we continue to use our cami procedures especially in those high workload environments.

Original NASA ASRS Text

Title: A321 flight crew reported overshooting a crossing restriction on the TYSSN3 arrival to LAS; with a wake vortex encounter cited as contributing to the workload.

Narrative: We were descending on the TYSSN3 arrival into Las Vegas. The KADDY Intersection has a crossing restriction of 12;000 FT and 250 KTS. The automation was used and we were meeting all altitude crossings accordingly. Prior to reaching KADDY we began picking up moderate wake turbulence from the preceding aircraft. The Captain (pilot flying) overrode the aircraft and shallowed the descent and it was now in a non-managed configuration. Also the aircraft was put into heading for maybe 5 seconds and he rearmed the NAV. The KADDY fix showed magenta and we were clearly going to make the restriction no problem.I was watching the descent and was waiting for it to level at the alt constraint of 12;000 FT before continuing down after KADDY. What happened is it went below 12;000 FT; I said to the Captain to watch his altitude; KADDY has a 12;000 FT restriction. At this time we were at 11;600 FT and ATC gave us direct to PRINO essentially deleting the KADDY crossing. ATC never said anything about going below 12;000 FT but we clearly descended early. We talked about what happened and realized the aircraft was not put back into managed descent so it didn't honor the constraint. We needed to make sure we continue to use our CAMI procedures especially in those high workload environments.

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.

A321 flight crew reported overshooting a crossing restriction on the TYSSN3 arrival to las; with a wake vortex encounter cited as contributing to the workload.