ATC radar lack of reception of transponder within 10 mi of dfw radar antenna.

Attributes
ACN	202501
Time
Date	199202
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : dfw
State Reference	TX
Altitude	msl bound lower : 4000 msl bound upper : 4000
Environment
Flight Conditions	Marginal
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : dfw
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Qualification	controller : radar
Experience	controller radar : 8
ASRS Report	202501
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	other controllera
Resolutory Action	none taken : unable
Consequence	faa : investigated
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Air carrier X an medium large transport was on approach to runway 13R at dfw. At approximately 8 mi final air carrier X's transponder was lost and did not return. No other transponder problems were noted with other aircraft. There appears to be a consistent problem with transponders on air carrier company aircraft. We receive their transponders normally far from the airport (20 plus mi) but the closer they are to the airport, the worse the reception. This occurs on both arrival and departure and on both radar systems. The problem at this facility appears to be limited to air carrier company medium large transport's aircraft.

Original NASA ASRS Text

Title: ATC RADAR LACK OF RECEPTION OF TRANSPONDER WITHIN 10 MI OF DFW RADAR ANTENNA.

Narrative: ACR X AN MLG WAS ON APCH TO RWY 13R AT DFW. AT APPROX 8 MI FINAL ACR X'S TRANSPONDER WAS LOST AND DID NOT RETURN. NO OTHER TRANSPONDER PROBLEMS WERE NOTED WITH OTHER ACFT. THERE APPEARS TO BE A CONSISTENT PROBLEM WITH TRANSPONDERS ON ACR COMPANY ACFT. WE RECEIVE THEIR TRANSPONDERS NORMALLY FAR FROM THE ARPT (20 PLUS MI) BUT THE CLOSER THEY ARE TO THE ARPT, THE WORSE THE RECEPTION. THIS OCCURS ON BOTH ARR AND DEP AND ON BOTH RADAR SYSTEMS. THE PROBLEM AT THIS FACILITY APPEARS TO BE LIMITED TO ACR COMPANY MLG'S ACFT.

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.