Light transport accepts visual but follows wrong aircraft when turning base.

Attributes
ACN	248002
Time
Date	199307
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iah
State Reference	TX
Altitude	msl bound lower : 4000 msl bound upper : 5000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iah tower : msy
Operator	common carrier : air carrier
Make Model Name	Light Transport
Navigation In Use	Other Other
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	IFR
Aircraft 2
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 200 flight time total : 5000 flight time type : 3500
ASRS Report	248002
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	conflict : airborne less severe non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : became reoriented flight crew : took evasive action other
Consequence	Other
Miss Distance	horizontal : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were vectored for a right downwind and slowed to 210 KTS at 6000 ft. The controller was very busy, on the verge of overload, with several aircraft complaining about multiple runway changes, runways 26 and 27, multiple vectors, turns, airspeed changes, etc. The WX was 2500 ft scattered to broken with building cumulus clouds through 6000 ft. The WX precluded our seeing any traffic at 12 O'clock. The controller with no warning or explanation called 'the traffic you're following is turning final for runway 26, a company medium large transport.' we looked at our 3 O'clock position and saw an medium large transport inbound for the runway. My first officer without asking me called the traffic in sight. The controller then cleared us 'follow that traffic cleared for the visual runway 26.' my first officer again answered without consultation 'follow him, cleared for the visual.' this took about 4-5 seconds from the initial traffic call. I was concerned about the clouds and our ability to maintain the visual. My first officer assured me he could keep the traffic in sight on his side of the aircraft. During this the radio continued at a nonstop, overloaded clip. I started a descent and turned onto right base. We were able to maintain visual with the medium large transport at our 2-3 O'clock position. At approximately 4000 ft and just prior to our turn to final the controller called with a frantic 'you followed the wrong aircraft, turn right heading 270 degrees and climb to 5000 ft.' he then continued his continuous litany with other aircraft. We were unable to answer him due to radio congestion. I immediately went to maximum power and entered a 45 degree bank right turn with a 20 degree pitch up climb since all I knew was there was another medium large transport headed toward me at 9 O'clock. My first officer saw the other medium large transport about 1-2 mi away also on base as we turned. The controller turned us again to 360 degrees and again did not wait for an answer. I feel this was caused by improper controller phraseology and procedures, heavy traffic, crew fatigue, 12TH leg in 27 hours, and a breakdown in cockpit communications.

Original NASA ASRS Text

Title: LTT ACCEPTS VISUAL BUT FOLLOWS WRONG ACFT WHEN TURNING BASE.

Narrative: WE WERE VECTORED FOR A R DOWNWIND AND SLOWED TO 210 KTS AT 6000 FT. THE CTLR WAS VERY BUSY, ON THE VERGE OF OVERLOAD, WITH SEVERAL ACFT COMPLAINING ABOUT MULTIPLE RWY CHANGES, RWYS 26 AND 27, MULTIPLE VECTORS, TURNS, AIRSPD CHANGES, ETC. THE WX WAS 2500 FT SCATTERED TO BROKEN WITH BUILDING CUMULUS CLOUDS THROUGH 6000 FT. THE WX PRECLUDED OUR SEEING ANY TFC AT 12 O'CLOCK. THE CTLR WITH NO WARNING OR EXPLANATION CALLED 'THE TFC YOU'RE FOLLOWING IS TURNING FINAL FOR RWY 26, A COMPANY MLG.' WE LOOKED AT OUR 3 O'CLOCK POS AND SAW AN MLG INBOUND FOR THE RWY. MY FO WITHOUT ASKING ME CALLED THE TFC IN SIGHT. THE CTLR THEN CLRED US 'FOLLOW THAT TFC CLRED FOR THE VISUAL RWY 26.' MY FO AGAIN ANSWERED WITHOUT CONSULTATION 'FOLLOW HIM, CLRED FOR THE VISUAL.' THIS TOOK ABOUT 4-5 SECONDS FROM THE INITIAL TFC CALL. I WAS CONCERNED ABOUT THE CLOUDS AND OUR ABILITY TO MAINTAIN THE VISUAL. MY FO ASSURED ME HE COULD KEEP THE TFC IN SIGHT ON HIS SIDE OF THE ACFT. DURING THIS THE RADIO CONTINUED AT A NONSTOP, OVERLOADED CLIP. I STARTED A DSCNT AND TURNED ONTO R BASE. WE WERE ABLE TO MAINTAIN VISUAL WITH THE MLG AT OUR 2-3 O'CLOCK POS. AT APPROX 4000 FT AND JUST PRIOR TO OUR TURN TO FINAL THE CTLR CALLED WITH A FRANTIC 'YOU FOLLOWED THE WRONG ACFT, TURN R HDG 270 DEGS AND CLB TO 5000 FT.' HE THEN CONTINUED HIS CONTINUOUS LITANY WITH OTHER ACFT. WE WERE UNABLE TO ANSWER HIM DUE TO RADIO CONGESTION. I IMMEDIATELY WENT TO MAX PWR AND ENTERED A 45 DEG BANK R TURN WITH A 20 DEG PITCH UP CLB SINCE ALL I KNEW WAS THERE WAS ANOTHER MLG HEADED TOWARD ME AT 9 O'CLOCK. MY FO SAW THE OTHER MLG ABOUT 1-2 MI AWAY ALSO ON BASE AS WE TURNED. THE CTLR TURNED US AGAIN TO 360 DEGS AND AGAIN DID NOT WAIT FOR AN ANSWER. I FEEL THIS WAS CAUSED BY IMPROPER CTLR PHRASEOLOGY AND PROCS, HVY TFC, CREW FATIGUE, 12TH LEG IN 27 HRS, AND A BREAKDOWN IN COCKPIT COMS.

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.