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B727-200 crew had erroneous position indications while on vectors for the ILS DME 09 approach at svmi.
| Attributes | |
| ACN | 511381 |
| Time | |
| Date | 200105 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : svmi.airport |
| State Reference | FO |
| Altitude | msl single value : 2000 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | other |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : svmi.tracon artcc : zau.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B727-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer & glide slope : 9 other other Other other vortac |
| Flight Phase | descent : approach |
| Route In Use | approach : instrument precision arrival : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : commercial pilot : instrument |
| ASRS Report | 511381 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | inflight encounter : weather inflight encounter other other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : glideslope bar, wx radar, cps other flight crewa other flight crewb |
| Resolutory Action | flight crew : returned to intended or assigned course |
| Consequence | other |
| Supplementary | |
| Problem Areas | Navigational Facility Weather |
| Primary Problem | Ambiguous |
Narrative:
On approach to miq the night of tue may we were cleared on a 130 degree heading to intercept localizer for ILS 09 to miq at initial altitude of 2000 ft. First officer was flying and had ILS. Monitoring VOR 272 degree radial. Aircraft was in clouds. VOR showed aircraft still north of 280 radial-ILS needle still pegged to the right, but GS needle showed aircraft beginning to go above GS. As VOR showed aircraft still on 280 radial-ILS needle immediately swung full scale to the left. Began immediate turn to left,broke out of clouds and saw the aircraft was well to right of centerline of runway. Crew felt that both ILS and VOR radial information was unreliable based on needle movements and subsequent position of aircraft. We were on the verge of going around to north when we broke out and were able to land. Identifiers for both ILS and VOR were good. Callback conversation with reporter revealed the following information: the no.2 navigation receiver was on the localizer, with 096 in the course window. And the no. 1 navigation receiver on the miq VOR with the 272 radial selected. The so was the first to notice the anomaly. The crew was also monitoring position with the GPS and aircraft WX radar. They have no idea why the problem occurred. Nothing was wrong with the aircraft navigation systems and no problems were reported with ground navigation aids. The crew flew into svmi all month and had no further problems.
Original NASA ASRS Text
Title: B727-200 CREW HAD ERRONEOUS POS INDICATIONS WHILE ON VECTORS FOR THE ILS DME 09 APCH AT SVMI.
Narrative: ON APCH TO MIQ THE NIGHT OF TUE MAY WE WERE CLRED ON A 130 DEG HEADING TO INTERCEPT LOC FOR ILS 09 TO MIQ AT INITIAL ALTITUDE OF 2000 FT. FO WAS FLYING AND HAD ILS. MONITORING VOR 272 DEG RADIAL. ACFT WAS IN CLOUDS. VOR SHOWED ACFT STILL N OF 280 RADIAL-ILS NEEDLE STILL PEGGED TO THE R, BUT GS NEEDLE SHOWED ACFT BEGINNING TO GO ABOVE GS. AS VOR SHOWED ACFT STILL ON 280 RADIAL-ILS NEEDLE IMMEDIATELY SWUNG FULL SCALE TO THE L. BEGAN IMMEDIATE TURN TO L,BROKE OUT OF CLOUDS AND SAW THE ACFT WAS WELL TO R OF CENTERLINE OF RWY. CREW FELT THAT BOTH ILS AND VOR RADIAL INFO WAS UNRELIABLE BASED ON NEEDLE MOVEMENTS AND SUBSEQUENT POS OF ACFT. WE WERE ON THE VERGE OF GOING AROUND TO N WHEN WE BROKE OUT AND WERE ABLE TO LAND. IDENTIFIERS FOR BOTH ILS AND VOR WERE GOOD. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE NO.2 NAV RECEIVER WAS ON THE LOC, WITH 096 IN THE COURSE WINDOW. AND THE NO. 1 NAV RECEIVER ON THE MIQ VOR WITH THE 272 RADIAL SELECTED. THE SO WAS THE FIRST TO NOTICE THE ANOMALY. THE CREW WAS ALSO MONITORING POS WITH THE GPS AND ACFT WX RADAR. THEY HAVE NO IDEA WHY THE PROB OCCURRED. NOTHING WAS WRONG WITH THE ACFT NAV SYSTEMS AND NO PROBS WERE RPTED WITH GND NAV AIDS. THE CREW FLEW INTO SVMI ALL MONTH AND HAD NO FURTHER PROBS.
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.