Air carrier aircraft deviated from assigned altitude in response to a TCASII RA.

Attributes
ACN	231634
Time
Date	199301
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : ord
State Reference	IL
Altitude	msl bound lower : 4000 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	descent : approach
Route In Use	approach : straight in arrival other
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 4
ASRS Report	231634
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Workload was high, ord was running simultaneous 27 visual approachs. Air carrier flight had been cleared for the visual approach around 18 DME. Air carrier flight says he has an 'RA' to climb which he did to 4500 ft. He was asked where the traffic was because there wasn't anyone closer than 3-4 mi in any direction. His response was the 'RA' told me to climb so we did. There was a clearance deviation of 500 ft. Communication was initiated by the TCASII aircraft, however, the communication was initiated after the maneuver. The controller was not aware this aircraft was TCASII equipped.

Original NASA ASRS Text

Title: ACR ACFT DEVIATED FROM ASSIGNED ALT IN RESPONSE TO A TCASII RA.

Narrative: WORKLOAD WAS HIGH, ORD WAS RUNNING SIMULTANEOUS 27 VISUAL APCHS. ACR FLT HAD BEEN CLRED FOR THE VISUAL APCH AROUND 18 DME. ACR FLT SAYS HE HAS AN 'RA' TO CLB WHICH HE DID TO 4500 FT. HE WAS ASKED WHERE THE TFC WAS BECAUSE THERE WASN'T ANYONE CLOSER THAN 3-4 MI IN ANY DIRECTION. HIS RESPONSE WAS THE 'RA' TOLD ME TO CLB SO WE DID. THERE WAS A CLRNC DEV OF 500 FT. COM WAS INITIATED BY THE TCASII ACFT, HOWEVER, THE COM WAS INITIATED AFTER THE MANEUVER. THE CTLR WAS NOT AWARE THIS ACFT WAS TCASII EQUIPPED.

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.