Near midair collision occurs after heading track deviation. See and avoid concept not exercised.

Attributes
ACN	222665
Time
Date	199209
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : dtw
State Reference	MI
Altitude	msl bound lower : 3000 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : dtw tower : pub
Operator	general aviation : corporate
Make Model Name	Small Transport
Flight Phase	cruise other 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	cruise other descent : approach
Route In Use	approach : visual enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 13500 flight time type : 4500
ASRS Report	222665
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : clearance non adherence : far other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Miss Distance	vertical : 300
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

My aircraft was cleared for a visual approach to runway 21R at dtw. This involved a right turn in from the north to the runway. We were issued traffic information on 2 aircraft. One, the traffic we were to follow to 21R and two, an medium large transport 11 O'clock 5 mi on a left base to runway 21C. Initially, I saw the traffic I was to follow. I then looked to find the second aircraft. I saw an aircraft that I believed was the 11 O'clock traffic and when I looked back I was unable to see the aircraft I was to follow. My attention was diverted while looking for the issued traffic and I overshot the extended centerline for 21R. Before I could react to the overshoot, an air carrier medium large transport Y appeared to my right and 300 ft or so below our aircraft. It was obvious that he had just passed underneath us on what would have been a collision course if we had been at the same altitude. I was in a slight right turn and the medium large transport appeared to be wings level or nearly so. How close we actually came when he passed beneath me I do not know. I do not know if the medium large transport was in fact the issued traffic I saw and assumed to be the issued could not have been the one with which we had just had our 'close encounter.' again, him to land on 21C and me to land on 21R.

Original NASA ASRS Text

Title: NMAC OCCURS AFTER HDG TRACK DEV. SEE AND AVOID CONCEPT NOT EXERCISED.

Narrative: MY ACFT WAS CLRED FOR A VISUAL APCH TO RWY 21R AT DTW. THIS INVOLVED A R TURN IN FROM THE N TO THE RWY. WE WERE ISSUED TFC INFO ON 2 ACFT. ONE, THE TFC WE WERE TO FOLLOW TO 21R AND TWO, AN MLG 11 O'CLOCK 5 MI ON A L BASE TO RWY 21C. INITIALLY, I SAW THE TFC I WAS TO FOLLOW. I THEN LOOKED TO FIND THE SECOND ACFT. I SAW AN ACFT THAT I BELIEVED WAS THE 11 O'CLOCK TFC AND WHEN I LOOKED BACK I WAS UNABLE TO SEE THE ACFT I WAS TO FOLLOW. MY ATTN WAS DIVERTED WHILE LOOKING FOR THE ISSUED TFC AND I OVERSHOT THE EXTENDED CTRLINE FOR 21R. BEFORE I COULD REACT TO THE OVERSHOOT, AN ACR MLG Y APPEARED TO MY R AND 300 FT OR SO BELOW OUR ACFT. IT WAS OBVIOUS THAT HE HAD JUST PASSED UNDERNEATH US ON WHAT WOULD HAVE BEEN A COLLISION COURSE IF WE HAD BEEN AT THE SAME ALT. I WAS IN A SLIGHT R TURN AND THE MLG APPEARED TO BE WINGS LEVEL OR NEARLY SO. HOW CLOSE WE ACTUALLY CAME WHEN HE PASSED BENEATH ME I DO NOT KNOW. I DO NOT KNOW IF THE MLG WAS IN FACT THE ISSUED TFC I SAW AND ASSUMED TO BE THE ISSUED COULD NOT HAVE BEEN THE ONE WITH WHICH WE HAD JUST HAD OUR 'CLOSE ENCOUNTER.' AGAIN, HIM TO LAND ON 21C AND ME TO LAND ON 21R.

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.