B757 TCASII RA descent into ord.

Attributes
ACN	439966
Time
Date	199906
Day	Fri
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : ord.airport
State Reference	IL
Altitude	msl bound lower : 10800 msl bound upper : 11300
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : c90.tracon
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	descent : vacating altitude
Route In Use	arrival star : bradford.arr
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : c90.tracon
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	439966
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : multi engine pilot : instrument
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter other non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : took precautionary avoidance action
Supplementary
Problem Areas	Environmental Factor ATC Human Performance
Primary Problem	Ambiguous

Narrative:

Ord approach. Location: bradford arrival to ord. Received descent from 11000 ft to 8000 ft. Descending through 10800 ft, received TCASII RA showing traffic 400 ft below with command to climb. Started climb and informed ATC. Received clear traffic at 11300 ft. Resumed descent to 8000 ft with ATC approval.

Original NASA ASRS Text

Title: B757 TCASII RA DSCNT INTO ORD.

Narrative: ORD APCH. LOCATION: BRADFORD ARR TO ORD. RECEIVED DSCNT FROM 11000 FT TO 8000 FT. DSNDING THROUGH 10800 FT, RECEIVED TCASII RA SHOWING TFC 400 FT BELOW WITH COMMAND TO CLB. STARTED CLB AND INFORMED ATC. RECEIVED CLR TFC AT 11300 FT. RESUMED DSCNT TO 8000 FT WITH ATC APPROVAL.

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.