DA50 reporter on ILS approach runway 4R receives red flags for localizer and GS on very short final ...

Attributes
ACN	370345
Time
Date	199705
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : mdw
State Reference	IL
Altitude	msl bound lower : 1340 msl bound upper : 1340
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : mdw
Operator	other
Make Model Name	Falcon 50
Operating Under FAR Part	Part 91
Flight Phase	descent : approach landing : missed approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	370345
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Navigational Facility
Air Traffic Incident	other

Narrative:

I was on the ILS approach to runway 4R at mdw and right after my arrival the airport was going to be switching arrs to runway 31C. I intercepted both the localizer and the GS as planned and began the descent. All indications were normal until reaching 400 ft above minimums at which time both the localizer and the GS became 'red flagged.' we executed a missed approach and later used the ILS to runway 31C and landed. After landing I questioned ATC regarding the status of the ILS to runway 4R and was told it had shut down on its own. The reason for this report is that I believe that since they were switching approach and runways, the ILS to runway 4 was shut down prematurely and if this is true it is a potentially dangerous situation. If I had missed seeing the 'red flags' and continued the approach this could easily have resulted in an aircraft accident. Let an aircraft inside the OM finish the approach before shutting it off and switching to another runway. Callback conversation with reporter revealed the following information: reporter sated he was about 1 1/2 mi on final when he did the missed approach. Reporter said that it was the ground controller he had talked with after landing about the shutdown of the ILS. Analyst conferred with person at mdw and learned that there have been some reported problems with the runway 4R ILS. Spokesperson indicated they would not turn off the runway 4R ILS when switching to the runway 31C ILS.

Original NASA ASRS Text

Title: DA50 RPTR ON ILS APCH RWY 4R RECEIVES RED FLAGS FOR LOC AND GS ON VERY SHORT FINAL AND EXECUTES MISSED APCH. ATC SAYS IT SHUT DOWN ON ITS OWN. AFTER THIS ACFT APCH, ATC WAS SWITCHING APCHS TO RWY 31C.

Narrative: I WAS ON THE ILS APCH TO RWY 4R AT MDW AND RIGHT AFTER MY ARR THE ARPT WAS GOING TO BE SWITCHING ARRS TO RWY 31C. I INTERCEPTED BOTH THE LOC AND THE GS AS PLANNED AND BEGAN THE DSCNT. ALL INDICATIONS WERE NORMAL UNTIL REACHING 400 FT ABOVE MINIMUMS AT WHICH TIME BOTH THE LOC AND THE GS BECAME 'RED FLAGGED.' WE EXECUTED A MISSED APCH AND LATER USED THE ILS TO RWY 31C AND LANDED. AFTER LNDG I QUESTIONED ATC REGARDING THE STATUS OF THE ILS TO RWY 4R AND WAS TOLD IT HAD SHUT DOWN ON ITS OWN. THE REASON FOR THIS RPT IS THAT I BELIEVE THAT SINCE THEY WERE SWITCHING APCH AND RWYS, THE ILS TO RWY 4 WAS SHUT DOWN PREMATURELY AND IF THIS IS TRUE IT IS A POTENTIALLY DANGEROUS SIT. IF I HAD MISSED SEEING THE 'RED FLAGS' AND CONTINUED THE APCH THIS COULD EASILY HAVE RESULTED IN AN ACFT ACCIDENT. LET AN ACFT INSIDE THE OM FINISH THE APCH BEFORE SHUTTING IT OFF AND SWITCHING TO ANOTHER RWY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SATED HE WAS ABOUT 1 1/2 MI ON FINAL WHEN HE DID THE MISSED APCH. RPTR SAID THAT IT WAS THE GND CTLR HE HAD TALKED WITH AFTER LNDG ABOUT THE SHUTDOWN OF THE ILS. ANALYST CONFERRED WITH PERSON AT MDW AND LEARNED THAT THERE HAVE BEEN SOME RPTED PROBS WITH THE RWY 4R ILS. SPOKESPERSON INDICATED THEY WOULD NOT TURN OFF THE RWY 4R ILS WHEN SWITCHING TO THE RWY 31C ILS.

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.

DA50 reporter on ILS approach runway 4R receives red flags for localizer and GS on very short final and executes missed approach. ATC says it shut down on its own. After this aircraft approach, ATC was switching approachs to runway 31C.