Large transport intercepts runway 21R rather than runway 21L localizer.

Attributes
ACN	250118
Time
Date	199308
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : dtw
State Reference	MI
Altitude	msl bound lower : 5000 msl bound upper : 5000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dtw
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 4000
ASRS Report	250118
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	other

Narrative:

Approaching detroit from the northeast. Airport was using runway 21. We were expecting runway 21L, initial contact with approach they told us runway 21R. We were surprised and happy because runway 21R would mean a shorter taxi to the gate. The approach controller gave us some heading and altitude changes and handed us off. Next approach controller gave us heading and altitude changes, and handed us off. Next approach controller cleared us down to 5000 ft and told us to intercept the localizer. At 5000 ft, on the runway 21R localizer we were above the GS, approximately 15 mi out so we requested a lower altitude. Response was something like turn left 10 degrees, descend to 4000 ft, intercept the localizer runway 21L. This was confusing. We asked confirm we are at runway 21R. This brought a negative response that we were never cleared for runway 21R, should be on runway 21L which we intercepted and had a normal landing. Believe that even if the airport is VFR the controllers should always say runway 21L localizer or runway 21R localizer when they clear aircraft to intercept. First controller told us runway 21R, next controller didn't change it or say anything about the runway. Next controller says intercept the localizer. I know dtw vectors aircraft in for the parallel's at 1000 ft separation. Excellent safety, probably that procedure prevented a conflict.

Original NASA ASRS Text

Title: LGT INTERCEPTS RWY 21R RATHER THAN RWY 21L LOC.

Narrative: APCHING DETROIT FROM THE NE. ARPT WAS USING RWY 21. WE WERE EXPECTING RWY 21L, INITIAL CONTACT WITH APCH THEY TOLD US RWY 21R. WE WERE SURPRISED AND HAPPY BECAUSE RWY 21R WOULD MEAN A SHORTER TAXI TO THE GATE. THE APCH CTLR GAVE US SOME HDG AND ALT CHANGES AND HANDED US OFF. NEXT APCH CTLR GAVE US HDG AND ALT CHANGES, AND HANDED US OFF. NEXT APCH CTLR CLRED US DOWN TO 5000 FT AND TOLD US TO INTERCEPT THE LOC. AT 5000 FT, ON THE RWY 21R LOC WE WERE ABOVE THE GS, APPROX 15 MI OUT SO WE REQUESTED A LOWER ALT. RESPONSE WAS SOMETHING LIKE TURN L 10 DEGS, DSND TO 4000 FT, INTERCEPT THE LOC RWY 21L. THIS WAS CONFUSING. WE ASKED CONFIRM WE ARE AT RWY 21R. THIS BROUGHT A NEGATIVE RESPONSE THAT WE WERE NEVER CLRED FOR RWY 21R, SHOULD BE ON RWY 21L WHICH WE INTERCEPTED AND HAD A NORMAL LNDG. BELIEVE THAT EVEN IF THE ARPT IS VFR THE CTLRS SHOULD ALWAYS SAY RWY 21L LOC OR RWY 21R LOC WHEN THEY CLR ACFT TO INTERCEPT. FIRST CTLR TOLD US RWY 21R, NEXT CTLR DIDN'T CHANGE IT OR SAY ANYTHING ABOUT THE RWY. NEXT CTLR SAYS INTERCEPT THE LOC. I KNOW DTW VECTORS ACFT IN FOR THE PARALLEL'S AT 1000 FT SEPARATION. EXCELLENT SAFETY, PROBABLY THAT PROC PREVENTED A CONFLICT.

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.