An air carrier flight crew was distraction by a TCASII alert, and descended through clearance altitu...

Attributes
ACN	296627
Time
Date	199502
Day	Sun
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : den
State Reference	CO
Altitude	msl bound lower : 13700 msl bound upper : 14000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : den
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	enroute airway : den
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp pilot : cfi
Experience	flight time last 90 days : 120 flight time total : 11000 flight time type : 2700
ASRS Report	296627
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 20000 flight time type : 1400
ASRS Report	296630
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While approaching denver at 15000 ft MSL, we were given a descent to 14000 ft. Received a TCASII TA during descent and saw an unidented target on the display. (Altitude not depicted.) we were both looking out the window when the altitude alert sounded. The first officer had descended through 14000-13700 ft. He immediately stopped the descent and was correcting back to 14000 ft when we were given a descent to 11000 ft and a turn to 080 degrees. Shortly thereafter, we received a frequency change. The rest of the approach/landing was uneventful. Supplemental information from acn 296630: 'out of 15000 ft for 14000 ft' call made by PNF and acknowledged by myself PF. TCASII 'traffic, traffic' TCASII display showed non-radar transponder traffic 11:30-12 O'clock at less than 5 mi.

Original NASA ASRS Text

Title: AN ACR FLC WAS DISTR BY A TCASII ALERT, AND DSNDED THROUGH CLRNC ALT.

Narrative: WHILE APCHING DENVER AT 15000 FT MSL, WE WERE GIVEN A DSCNT TO 14000 FT. RECEIVED A TCASII TA DURING DSCNT AND SAW AN UNIDENTED TARGET ON THE DISPLAY. (ALT NOT DEPICTED.) WE WERE BOTH LOOKING OUT THE WINDOW WHEN THE ALT ALERT SOUNDED. THE FO HAD DSNDED THROUGH 14000-13700 FT. HE IMMEDIATELY STOPPED THE DSCNT AND WAS CORRECTING BACK TO 14000 FT WHEN WE WERE GIVEN A DSCNT TO 11000 FT AND A TURN TO 080 DEGS. SHORTLY THEREAFTER, WE RECEIVED A FREQ CHANGE. THE REST OF THE APCH/LNDG WAS UNEVENTFUL. SUPPLEMENTAL INFO FROM ACN 296630: 'OUT OF 15000 FT FOR 14000 FT' CALL MADE BY PNF AND ACKNOWLEDGED BY MYSELF PF. TCASII 'TFC, TFC' TCASII DISPLAY SHOWED NON-RADAR XPONDER TFC 11:30-12 O'CLOCK AT LESS THAN 5 MI.

Data retrieved from NASA's ASRS site as of July 2007 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.

An air carrier flight crew was distraction by a TCASII alert, and descended through clearance altitude.