A C172 has an near midair collision with an EMB120 4 mi east of runway 26L at iah, tx.

Attributes
ACN	453078
Time
Date	199910
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iah.airport
State Reference	TX
Altitude	msl single value : 1150
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : iah.tower
Operator	general aviation : corporate
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : enroute altitude change
Route In Use	enroute : on vectors
Flight Plan	None
Aircraft 2
Controlling Facilities	tower : iah.tower
Operator	common carrier : air carrier
Make Model Name	Brasilia EMB-120 All Series
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 26l
Flight Phase	descent : vacating altitude descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : commercial
Experience	flight time last 90 days : 95 flight time total : 1390 flight time type : 400
ASRS Report	453078
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	conflict : nmac non adherence : far non adherence : required legal separation
Independent Detector	other controllerb other flight crewa
Resolutory Action	controller : issued alert flight crew : took precautionary avoidance action
Miss Distance	horizontal : 350 vertical : 350
Supplementary
Problem Areas	Airspace Structure Flight Crew Human Performance ATC Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft X had just passed south of the runway 26 and runway 27 approach courses at 1500 ft MSL as instructed by tower. Aircraft X, while on a heading of 150 degrees as instructed by tower, requested to proceed north along united states highway 59. During the turn, at tower's request, aircraft X was descending to at or below 1400 ft MSL. Aircraft X was advised of aircraft Y, who was on final to runway 26. Aircraft X advised traffic was in sight and continued a descent toward 1000 ft MSL to provide vertical separation from aircraft Y. Aircraft Y passed approximately 350 ft above and ahead of aircraft X from right to left. Although class B separation criteria had been met, future vectors for traffic watch aircraft that would place them close to the approach ends of runway 26 and runway 27, would place them above the final approach traffic rather than underneath.

Original NASA ASRS Text

Title: A C172 HAS AN NMAC WITH AN EMB120 4 MI E OF RWY 26L AT IAH, TX.

Narrative: ACFT X HAD JUST PASSED S OF THE RWY 26 AND RWY 27 APCH COURSES AT 1500 FT MSL AS INSTRUCTED BY TWR. ACFT X, WHILE ON A HDG OF 150 DEGS AS INSTRUCTED BY TWR, REQUESTED TO PROCEED N ALONG UNITED STATES HWY 59. DURING THE TURN, AT TWR'S REQUEST, ACFT X WAS DSNDING TO AT OR BELOW 1400 FT MSL. ACFT X WAS ADVISED OF ACFT Y, WHO WAS ON FINAL TO RWY 26. ACFT X ADVISED TFC WAS IN SIGHT AND CONTINUED A DSCNT TOWARD 1000 FT MSL TO PROVIDE VERT SEPARATION FROM ACFT Y. ACFT Y PASSED APPROX 350 FT ABOVE AND AHEAD OF ACFT X FROM R TO L. ALTHOUGH CLASS B SEPARATION CRITERIA HAD BEEN MET, FUTURE VECTORS FOR TFC WATCH ACFT THAT WOULD PLACE THEM CLOSE TO THE APCH ENDS OF RWY 26 AND RWY 27, WOULD PLACE THEM ABOVE THE FINAL APCH TFC RATHER THAN UNDERNEATH.

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.