Dtw airport radio blind spot.

Attributes
ACN	180128
Time
Date	199106
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dtw
State Reference	MI
Altitude	agl bound lower : 0 agl bound upper : 1500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : dtw
Operator	general aviation : corporate
Make Model Name	Light Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach landing other
Flight Plan	IFR
Aircraft 2
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	ground : holding
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 60 flight time total : 11000 flight time type : 3000
ASRS Report	180128
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other
Situations
ATC Facility	other physical facility

Narrative:

On final for runway 21L at dtw, we had been cleared to land. The tower cleared aircraft Y into position on the runway. Aircraft Y did not respond. We could see aircraft Y on the taxiway on the east side of the runway. After several attempts by the tower, it sounded like a different transmitter was used since the quality of the transmission was different. At that point aircraft Y acknowledged the transmission, and was told to hold short of the runway since we were on short final at this point. There was never a point where there was a conflict. We have had similar situations in the past on the ground at dtw on the east side of runway 3R-21L during the past several yrs. Where it has not caused us a problem, I see this as a potential safety hazard. I spoke with the acting facility manager, who has been on the job for only 30 days. He was unaware of the situation. Callback conversation with reporter revealed the following: reporter stated the blind area east of the runway 3R/21L is a known radio blind. This happens when the tower is transmitting ont he primary transmitters. When the tower changes to the backup transmitters, the aircraft can heard the tower. The reporter said this problem has been happening for yrs.

Original NASA ASRS Text

Title: DTW ARPT RADIO BLIND SPOT.

Narrative: ON FINAL FOR RWY 21L AT DTW, WE HAD BEEN CLRED TO LAND. THE TWR CLRED ACFT Y INTO POS ON THE RWY. ACFT Y DID NOT RESPOND. WE COULD SEE ACFT Y ON THE TXWY ON THE E SIDE OF THE RWY. AFTER SEVERAL ATTEMPTS BY THE TWR, IT SOUNDED LIKE A DIFFERENT XMITTER WAS USED SINCE THE QUALITY OF THE XMISSION WAS DIFFERENT. AT THAT POINT ACFT Y ACKNOWLEDGED THE XMISSION, AND WAS TOLD TO HOLD SHORT OF THE RWY SINCE WE WERE ON SHORT FINAL AT THIS POINT. THERE WAS NEVER A POINT WHERE THERE WAS A CONFLICT. WE HAVE HAD SIMILAR SITUATIONS IN THE PAST ON THE GND AT DTW ON THE E SIDE OF RWY 3R-21L DURING THE PAST SEVERAL YRS. WHERE IT HAS NOT CAUSED US A PROB, I SEE THIS AS A POTENTIAL SAFETY HAZARD. I SPOKE WITH THE ACTING FAC MGR, WHO HAS BEEN ON THE JOB FOR ONLY 30 DAYS. HE WAS UNAWARE OF THE SITUATION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATED THE BLIND AREA E OF THE RWY 3R/21L IS A KNOWN RADIO BLIND. THIS HAPPENS WHEN THE TWR IS XMITTING ONT HE PRIMARY XMITTERS. WHEN THE TWR CHANGES TO THE BACKUP XMITTERS, THE ACFT CAN HEARD THE TWR. THE RPTR SAID THIS PROB HAS BEEN HAPPENING FOR YRS.

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.