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Reverse sensing noted by cpr flight crew as they attempt an ILS to yip runway 23L. After some confusion the aircraft is vectored back for another approach. Flight crew correctly judged that the tower controller had set up the wrong ILS for their approach.
| Attributes | |
| ACN | 394720 |
| Time | |
| Date | 199802 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : yip |
| State Reference | MI |
| Altitude | msl bound lower : 2500 msl bound upper : 3000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : dtw tower : yip |
| Operator | general aviation : corporate |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | ils localizer & glide slope : lsw Other |
| Flight Phase | descent : approach landing : missed approach |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : cfi pilot : atp pilot : instrument |
| Experience | flight time last 90 days : 80 flight time total : 3675 flight time type : 18 |
| ASRS Report | 394720 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 70 flight time total : 11150 flight time type : 350 |
| ASRS Report | 394878 |
| Events | |
| Anomaly | non adherence : clearance non adherence : published procedure other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | other |
| Situations | |
| ATC Facility | procedure or policy : unspecified |
Narrative:
Inbound to yip we were northwest of the localizer for ILS runway 23L approach on an easterly heading to intercept the localizer. The HSI indication was wrong for our position as the CDI needle showed that we were southeast of the localizer, while we were actually northeast. We waited for the needle on the CDI to change presuming we were too far to the northwest to get a good signal for a correct display. However we did rechk the localizer frequency to make sure it was correct. We thought there was a chance we were getting a reverse sensing indication on the HSI even with the correct course set in on the HSI. Finally the needle centered and then moved full deflection to the northeast showing we were southeast of course. The aircraft has a GPS, a king KLN90B approach certified with a moving map display that we were using to back up our position on the approach. We had carrs final approach fix indicated on the GPS so we had a good reference for our course. The tower called as we were turning west to correct our course even though the localizer needle said to turn east. The tower called and said we were southeast of the localizer and at that time the localizer needle went from full left (southeast) to full right (northeast) deflection. We stated to the tower that something was wrong as we turned wbound to recapture the localizer. The tower made a statement to the effect that they were changing some switches and that all should be okay. We descended from 3000 ft to 2500 ft as we were above the GS to try and capture the ILS but by this time we decided we did not trust the localizer even though it had centered, we just felt uneasy. We stated to the tower we were not sure if the gauges were showing us the correct display. The tower gave us a 230 degree heading and told to maintain 3000 ft. We took the heading and climbed to 3000 ft. Then we were given a right turn to 360 degrees and sent back to approach controller for another approach. On the second approach all navigation gauges functioned correctly (normally) and we completed the ILS runway 23L approach. The approach controller mentioned that maybe the tower had turned on the ILS runway 5R approach for a moment. That is our conclusion as to why our gauges were reading as they were. We had reverse sensing as we were swbound northeast of the ILS antenna for runway 5. Fortunately no other traffic was affected. The tower should never change ILS approachs while an aircraft's trying to use one.
Original NASA ASRS Text
Title: REVERSE SENSING NOTED BY CPR FLC AS THEY ATTEMPT AN ILS TO YIP RWY 23L. AFTER SOME CONFUSION THE ACFT IS VECTORED BACK FOR ANOTHER APCH. FLC CORRECTLY JUDGED THAT THE TWR CTLR HAD SET UP THE WRONG ILS FOR THEIR APCH.
Narrative: INBOUND TO YIP WE WERE NW OF THE LOC FOR ILS RWY 23L APCH ON AN EASTERLY HEADING TO INTERCEPT THE LOC. THE HSI INDICATION WAS WRONG FOR OUR POS AS THE CDI NEEDLE SHOWED THAT WE WERE SE OF THE LOC, WHILE WE WERE ACTUALLY NE. WE WAITED FOR THE NEEDLE ON THE CDI TO CHANGE PRESUMING WE WERE TOO FAR TO THE NW TO GET A GOOD SIGNAL FOR A CORRECT DISPLAY. HOWEVER WE DID RECHK THE LOC FREQ TO MAKE SURE IT WAS CORRECT. WE THOUGHT THERE WAS A CHANCE WE WERE GETTING A REVERSE SENSING INDICATION ON THE HSI EVEN WITH THE CORRECT COURSE SET IN ON THE HSI. FINALLY THE NEEDLE CTRED AND THEN MOVED FULL DEFLECTION TO THE NE SHOWING WE WERE SE OF COURSE. THE ACFT HAS A GPS, A KING KLN90B APCH CERTIFIED WITH A MOVING MAP DISPLAY THAT WE WERE USING TO BACK UP OUR POS ON THE APCH. WE HAD CARRS FINAL APCH FIX INDICATED ON THE GPS SO WE HAD A GOOD REF FOR OUR COURSE. THE TWR CALLED AS WE WERE TURNING W TO CORRECT OUR COURSE EVEN THOUGH THE LOC NEEDLE SAID TO TURN E. THE TWR CALLED AND SAID WE WERE SE OF THE LOC AND AT THAT TIME THE LOC NEEDLE WENT FROM FULL L (SE) TO FULL R (NE) DEFLECTION. WE STATED TO THE TWR THAT SOMETHING WAS WRONG AS WE TURNED WBOUND TO RECAPTURE THE LOC. THE TWR MADE A STATEMENT TO THE EFFECT THAT THEY WERE CHANGING SOME SWITCHES AND THAT ALL SHOULD BE OKAY. WE DSNDED FROM 3000 FT TO 2500 FT AS WE WERE ABOVE THE GS TO TRY AND CAPTURE THE ILS BUT BY THIS TIME WE DECIDED WE DID NOT TRUST THE LOC EVEN THOUGH IT HAD CTRED, WE JUST FELT UNEASY. WE STATED TO THE TWR WE WERE NOT SURE IF THE GAUGES WERE SHOWING US THE CORRECT DISPLAY. THE TWR GAVE US A 230 DEG HDG AND TOLD TO MAINTAIN 3000 FT. WE TOOK THE HEADING AND CLBED TO 3000 FT. THEN WE WERE GIVEN A R TURN TO 360 DEGS AND SENT BACK TO APCH CTLR FOR ANOTHER APCH. ON THE SECOND APCH ALL NAV GAUGES FUNCTIONED CORRECTLY (NORMALLY) AND WE COMPLETED THE ILS RWY 23L APCH. THE APCH CTLR MENTIONED THAT MAYBE THE TWR HAD TURNED ON THE ILS RWY 5R APCH FOR A MOMENT. THAT IS OUR CONCLUSION AS TO WHY OUR GAUGES WERE READING AS THEY WERE. WE HAD REVERSE SENSING AS WE WERE SWBOUND NE OF THE ILS ANTENNA FOR RWY 5. FORTUNATELY NO OTHER TFC WAS AFFECTED. THE TWR SHOULD NEVER CHANGE ILS APCHS WHILE AN ACFT'S TRYING TO USE ONE.
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.