An air carrier medium large transport climbed in response to a TCASII command.

Attributes
ACN	224189
Time
Date	199210
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : den
State Reference	CO
Altitude	msl bound lower : 12000 msl bound upper : 12300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : den
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : instrument pilot : flight engineer
Experience	flight time last 90 days : 230 flight time total : 6000 flight time type : 230
ASRS Report	224189
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 150 flight time type : 730
ASRS Report	224007
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance non adherence : required legal separation other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : took evasive action flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation other

Narrative:

We were level at 12000 ft, our assigned altitude. We were on assigned heading and airspeed. We received a TCASII alert on traffic at 1 O'clock position and 13000 ft. We spotted the aircraft visually. It appeared to fly above and behind our position. (The aircraft was an airline jet). We then received a climb RA. We notified ATC of our climb RA, turned off the autoplt and climbed approximately 2 or 300 ft as instructed by the RA. We then received a 'clear of conflict' message and returned to 12000 ft. We were told by ATC that the RA steered us toward another aircraft above. The TCASII tested ok both before and after the flight. It seems like TCASII tolerance is more restrictive than ATC separation tolerance. ATC sometimes vector aircraft near each other and RA's result. Perhaps TCASII tolerance should be taken into account in ATC vector separation.

Original NASA ASRS Text

Title: AN ACR MLG CLBED IN RESPONSE TO A TCASII COMMAND.

Narrative: WE WERE LEVEL AT 12000 FT, OUR ASSIGNED ALT. WE WERE ON ASSIGNED HDG AND AIRSPD. WE RECEIVED A TCASII ALERT ON TFC AT 1 O'CLOCK POS AND 13000 FT. WE SPOTTED THE ACFT VISUALLY. IT APPEARED TO FLY ABOVE AND BEHIND OUR POS. (THE ACFT WAS AN AIRLINE JET). WE THEN RECEIVED A CLB RA. WE NOTIFIED ATC OF OUR CLB RA, TURNED OFF THE AUTOPLT AND CLBED APPROX 2 OR 300 FT AS INSTRUCTED BY THE RA. WE THEN RECEIVED A 'CLR OF CONFLICT' MESSAGE AND RETURNED TO 12000 FT. WE WERE TOLD BY ATC THAT THE RA STEERED US TOWARD ANOTHER ACFT ABOVE. THE TCASII TESTED OK BOTH BEFORE AND AFTER THE FLT. IT SEEMS LIKE TCASII TOLERANCE IS MORE RESTRICTIVE THAN ATC SEPARATION TOLERANCE. ATC SOMETIMES VECTOR ACFT NEAR EACH OTHER AND RA'S RESULT. PERHAPS TCASII TOLERANCE SHOULD BE TAKEN INTO ACCOUNT IN ATC VECTOR SEPARATION.

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.