Medium large transport crew had altitude bust on descent, and received a TCASII TA warning.

Attributes
ACN	405180
Time
Date	199804
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : esl
State Reference	WV
Altitude	msl bound lower : 6700 msl bound upper : 7000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	other : unknown
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 6500 flight time type : 1580
ASRS Report	405180
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Miss Distance	vertical : 700
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

During descent on arrival the captain descended approximately 200-300 ft below leveloff altitude of 7000 ft. We received a TA below us showing 700 ft of separation. He immediately corrected. At that same time ATC contacted us to correct our altitude, and he did. The captain was given many altitude and heading changes on our descent. At one point they gave us an altitude of 11000 ft and then changed it back to 12000 ft and also gave us a different runway, so the captain had to brief two approachs. I was finishing the approach descent check as well as looking over our new approach as well as working the radios when the deviation occurred. I think the distractions of so many changes is the reason for the minor altitude deviation.

Original NASA ASRS Text

Title: MLG CREW HAD ALT BUST ON DSCNT, AND RECEIVED A TCASII TA WARNING.

Narrative: DURING DSCNT ON ARR THE CAPT DSNDED APPROX 200-300 FT BELOW LEVELOFF ALT OF 7000 FT. WE RECEIVED A TA BELOW US SHOWING 700 FT OF SEPARATION. HE IMMEDIATELY CORRECTED. AT THAT SAME TIME ATC CONTACTED US TO CORRECT OUR ALT, AND HE DID. THE CAPT WAS GIVEN MANY ALT AND HEADING CHANGES ON OUR DSCNT. AT ONE POINT THEY GAVE US AN ALT OF 11000 FT AND THEN CHANGED IT BACK TO 12000 FT AND ALSO GAVE US A DIFFERENT RWY, SO THE CAPT HAD TO BRIEF TWO APCHS. I WAS FINISHING THE APCH DSCNT CHK AS WELL AS LOOKING OVER OUR NEW APCH AS WELL AS WORKING THE RADIOS WHEN THE DEV OCCURRED. I THINK THE DISTRACTIONS OF SO MANY CHANGES IS THE REASON FOR THE MINOR ALTDEV.

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.