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

Attributes
ACN	233917
Time
Date	199302
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : iah
State Reference	TX
Altitude	msl bound lower : 4000 msl bound upper : 4600
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iah tower : whp
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 7000 flight time type : 1000
ASRS Report	233917
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 250 flight time total : 11400
ASRS Report	234098
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance 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	faa : reviewed incident with flight crew
Miss Distance	horizontal : 3000 vertical : 500
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were approaching kiah to land -- assigned a westerly heading and an altitude of 4000 ft on a modified downwind. There were 8-10 aircraft in the immediate area. Approach control frequency was very congested. We were advised of an aircraft ahead about 4-5 mi, northbound at 3500 ft and maneuvering VFR at 3500 ft. We had no visual contact, but had a target 400 ft below us at 12 O'clock on TCASII. As we flew closer, the target turned yellow -- no visual contact (unable to contact approach). The target turned to red, an RA was given, i.e., 'climb, climb.' we climbed to plus/minus 4600 ft and noticed a high wing single engine land aircraft at our 3 O'clock position about 1/2 mi away. We told approach control and descended back to 4000 ft. After landing, we called ATC and their response was that they denied responsibility since they 'told' us about the traffic. They didn't fault us for climbing to 4600 ft since we had a valid RA and responded in the correct way in accordance with our training standards. The main 'trigger' in this situation is that the small aircraft was 400 ft below us on TCASII which is what our TCASII and we responded to (regardless of his 'actual' altitude).

Original NASA ASRS Text

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

Narrative: WE WERE APCHING KIAH TO LAND -- ASSIGNED A WESTERLY HDG AND AN ALT OF 4000 FT ON A MODIFIED DOWNWIND. THERE WERE 8-10 ACFT IN THE IMMEDIATE AREA. APCH CTL FREQ WAS VERY CONGESTED. WE WERE ADVISED OF AN ACFT AHEAD ABOUT 4-5 MI, NBOUND AT 3500 FT AND MANEUVERING VFR AT 3500 FT. WE HAD NO VISUAL CONTACT, BUT HAD A TARGET 400 FT BELOW US AT 12 O'CLOCK ON TCASII. AS WE FLEW CLOSER, THE TARGET TURNED YELLOW -- NO VISUAL CONTACT (UNABLE TO CONTACT APCH). THE TARGET TURNED TO RED, AN RA WAS GIVEN, I.E., 'CLB, CLB.' WE CLBED TO PLUS/MINUS 4600 FT AND NOTICED A HIGH WING SINGLE ENG LAND ACFT AT OUR 3 O'CLOCK POS ABOUT 1/2 MI AWAY. WE TOLD APCH CTL AND DSNDED BACK TO 4000 FT. AFTER LNDG, WE CALLED ATC AND THEIR RESPONSE WAS THAT THEY DENIED RESPONSIBILITY SINCE THEY 'TOLD' US ABOUT THE TFC. THEY DIDN'T FAULT US FOR CLBING TO 4600 FT SINCE WE HAD A VALID RA AND RESPONDED IN THE CORRECT WAY IN ACCORDANCE WITH OUR TRAINING STANDARDS. THE MAIN 'TRIGGER' IN THIS SIT IS THAT THE SMA WAS 400 FT BELOW US ON TCASII WHICH IS WHAT OUR TCASII AND WE RESPONDED TO (REGARDLESS OF HIS 'ACTUAL' ALT).

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.