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False low altitude warning causes air carrier go around with 25 minutes extra flight time to reposition for second approach. ATCT local controller says false warnings are frequent on this approach.
| Attributes | |
| ACN | 98749 |
| Time | |
| Date | 198811 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : phl |
| State Reference | PA |
| Altitude | agl bound lower : 500 agl bound upper : 500 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : phl |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent : approach landing : go around |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 8000 flight time type : 5000 |
| ASRS Report | 98749 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 16000 flight time type : 2500 |
| ASRS Report | 98777 |
| Events | |
| Anomaly | other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | other other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Navigational Facility |
| Air Traffic Incident | other |
| Situations | |
| ATC Facility | other physical facility |
Narrative:
On approach to phl runway 27R, 11/sun/88, at 500' with aircraft instrumentation indicating on course and glide path, the female tower controller advised twice in serious tone to check our altitude immediately that she had an altitude alert that we were 1 mi and 500'. Our indications agreed with the warning. Visibility was 1/4 mi with 6000 RVR on 27R. Because we were at the exact point she said we were and we could not assess if we had a problem, we executed missed approach procedures to assess problem. She asked if we needed any assistance. We replied no, because all our indications, after checking and identifying all radios, appeared to be normal. We were then told by controller that false alerts were common in that particular area, but they were required to issue them anyway. This issuance of false alert was very disconcerting, to say the least. We were then vectored for another approach, being about #15, it took about 25 minutes. We were in heavy turbulence and windshear conditions. A closely monitored approach and landing were made, everything being normal. Fuel was not a problem as we had taken full tanks from tampa. I feel this false alert created an unnecessarily bad situation.
Original NASA ASRS Text
Title: FALSE LOW ALT WARNING CAUSES ACR GO AROUND WITH 25 MINUTES EXTRA FLT TIME TO REPOSITION FOR SECOND APCH. ATCT LCL CTLR SAYS FALSE WARNINGS ARE FREQUENT ON THIS APCH.
Narrative: ON APCH TO PHL RWY 27R, 11/SUN/88, AT 500' WITH ACFT INSTRUMENTATION INDICATING ON COURSE AND GLIDE PATH, THE FEMALE TWR CTLR ADVISED TWICE IN SERIOUS TONE TO CHECK OUR ALT IMMEDIATELY THAT SHE HAD AN ALT ALERT THAT WE WERE 1 MI AND 500'. OUR INDICATIONS AGREED WITH THE WARNING. VISIBILITY WAS 1/4 MI WITH 6000 RVR ON 27R. BECAUSE WE WERE AT THE EXACT POINT SHE SAID WE WERE AND WE COULD NOT ASSESS IF WE HAD A PROBLEM, WE EXECUTED MISSED APCH PROCEDURES TO ASSESS PROBLEM. SHE ASKED IF WE NEEDED ANY ASSISTANCE. WE REPLIED NO, BECAUSE ALL OUR INDICATIONS, AFTER CHECKING AND IDENTIFYING ALL RADIOS, APPEARED TO BE NORMAL. WE WERE THEN TOLD BY CTLR THAT FALSE ALERTS WERE COMMON IN THAT PARTICULAR AREA, BUT THEY WERE REQUIRED TO ISSUE THEM ANYWAY. THIS ISSUANCE OF FALSE ALERT WAS VERY DISCONCERTING, TO SAY THE LEAST. WE WERE THEN VECTORED FOR ANOTHER APCH, BEING ABOUT #15, IT TOOK ABOUT 25 MINUTES. WE WERE IN HEAVY TURB AND WINDSHEAR CONDITIONS. A CLOSELY MONITORED APCH AND LNDG WERE MADE, EVERYTHING BEING NORMAL. FUEL WAS NOT A PROBLEM AS WE HAD TAKEN FULL TANKS FROM TAMPA. I FEEL THIS FALSE ALERT CREATED AN UNNECESSARILY BAD SITUATION.
Data retrieved from NASA's ASRS site as of August 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.