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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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On ILS intercept, autoplt coupled for the approach, it captured a false GS signal and commenced descent prior to the descent point. Reporter captain recognized the discrepancy, disconnected the autoplt and, after climbing to the correct altitude, recoupled the autoplt. All normal thereafter. A new hotel on the approach path is causing the false GS, according to a sju approach controller who was on the flight.
| Attributes | |
| ACN | 344493 |
| Time | |
| Date | 199608 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : sju |
| State Reference | PR |
| Altitude | msl bound lower : 1300 msl bound upper : 1600 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : sju |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 23800 flight time type : 5000 |
| ASRS Report | 344493 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
| Situations | |
| Airport | other physical facility |
| Navigational Aid | Unspecified |
Narrative:
Inbound on radar vector to intercept sju runway 8 ILS level at 1600 ft to cross OM at 1600 ft. Approach gave us a turn to intercept and called VFR traffic in the turn. While in the turn I felt autoplt capture ILS localizer and GS and start down. Upon coming back into cockpit I noticed we were approaching 1300 ft altitude and not yet to the OM. I disconnected the autoplt and climbed back to 1600 ft, reset flight director, and recoupled the autoplt. Rest of approach was uneventful. Autoplt had captured false GS outside the OM. On this flight we had an FAA sju approach controller on a familiarization flight. After this incident she informed us that sju approach control was aware of the problem. It is being caused by a new hotel in the approach path off sju runway 8, but they (sju approach control) can't get anything done as it will raise the runway 8 minimums.
Original NASA ASRS Text
Title: ON ILS INTERCEPT, AUTOPLT COUPLED FOR THE APCH, IT CAPTURED A FALSE GS SIGNAL AND COMMENCED DSCNT PRIOR TO THE DSCNT POINT. RPTR CAPT RECOGNIZED THE DISCREPANCY, DISCONNECTED THE AUTOPLT AND, AFTER CLBING TO THE CORRECT ALT, RECOUPLED THE AUTOPLT. ALL NORMAL THEREAFTER. A NEW HOTEL ON THE APCH PATH IS CAUSING THE FALSE GS, ACCORDING TO A SJU APCH CTLR WHO WAS ON THE FLT.
Narrative: INBOUND ON RADAR VECTOR TO INTERCEPT SJU RWY 8 ILS LEVEL AT 1600 FT TO CROSS OM AT 1600 FT. APCH GAVE US A TURN TO INTERCEPT AND CALLED VFR TFC IN THE TURN. WHILE IN THE TURN I FELT AUTOPLT CAPTURE ILS LOC AND GS AND START DOWN. UPON COMING BACK INTO COCKPIT I NOTICED WE WERE APCHING 1300 FT ALT AND NOT YET TO THE OM. I DISCONNECTED THE AUTOPLT AND CLBED BACK TO 1600 FT, RESET FLT DIRECTOR, AND RECOUPLED THE AUTOPLT. REST OF APCH WAS UNEVENTFUL. AUTOPLT HAD CAPTURED FALSE GS OUTSIDE THE OM. ON THIS FLT WE HAD AN FAA SJU APCH CTLR ON A FAMILIARIZATION FLT. AFTER THIS INCIDENT SHE INFORMED US THAT SJU APCH CTL WAS AWARE OF THE PROB. IT IS BEING CAUSED BY A NEW HOTEL IN THE APCH PATH OFF SJU RWY 8, BUT THEY (SJU APCH CTL) CAN'T GET ANYTHING DONE AS IT WILL RAISE THE RWY 8 MINIMUMS.
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.