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B737-300 crew on automatic ILS approach to runway 27L at ord intercept a false GS and cross wavie intersection about 1000 ft low.
| Attributes | |
| ACN | 482987 |
| Time | |
| Date | 200008 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | intersection : wavie |
| State Reference | IL |
| Altitude | msl bound lower : 4000 msl bound upper : 5000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | ils localizer & glide slope : 27l other |
| 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 : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 17000 flight time type : 4000 |
| ASRS Report | 482987 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : instrument pilot : commercial |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : published procedure other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented |
| Supplementary | |
| Problem Areas | Navigational Facility Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were on a vector to intercept the runway 27L ILS. We were told to maintain 5000 ft until crossing wavie and then cleared for the approach. The autoplt captured a false GS and we crossed wavie at about 4000 ft. The controller saw it and then cleared us to 3000 ft and for the approach. There was no conflict. You have to be aware that false GS capture happens and watch the DME at all times.
Original NASA ASRS Text
Title: B737-300 CREW ON AUTO ILS APCH TO RWY 27L AT ORD INTERCEPT A FALSE GS AND CROSS WAVIE INTXN ABOUT 1000 FT LOW.
Narrative: WE WERE ON A VECTOR TO INTERCEPT THE RWY 27L ILS. WE WERE TOLD TO MAINTAIN 5000 FT UNTIL XING WAVIE AND THEN CLRED FOR THE APCH. THE AUTOPLT CAPTURED A FALSE GS AND WE CROSSED WAVIE AT ABOUT 4000 FT. THE CTLR SAW IT AND THEN CLRED US TO 3000 FT AND FOR THE APCH. THERE WAS NO CONFLICT. YOU HAVE TO BE AWARE THAT FALSE GS CAPTURE HAPPENS AND WATCH THE DME AT ALL TIMES.
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.