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Flight crew of large transport on ILS approach descends below the published altitude. A low altitude alert results.
| Attributes | |
| ACN | 405779 |
| Time | |
| Date | 199806 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : phl |
| State Reference | PA |
| Altitude | msl bound lower : 1200 msl bound upper : 1800 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : phl |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 65 flight time total : 17000 flight time type : 65 |
| ASRS Report | 405779 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | non adherence : clearance non adherence : published procedure other spatial deviation |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : became reoriented other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
On an ILS approach to phl we were cleared for the runway 9R approach, I set the aad for 2000 ft. When we were inside 14 DME I set the aad for 1800 ft (our procedure). The captain reset the aad to 3100 ft. This confused me so I looked at the approach plate to make sure what I had done was correct. We were inside 13 DME so I reset the aad to 1800 ft. The captain then told me he did not want to hear the aad tone go off so he reset the aad to 3100 ft. All this time he was descending. I should have caught his descending but I did not. At this same time we were handed off to phl tower. They must have tried to call us the same time I was calling them. They told us they had a low altitude warning. This was the first time I noticed how low we were. The captain started climbing (we were 1400 ft AGL). I told him to increase his climb rate and he did. We were at 1800 ft at the OM. We had both been on duty for about 12 hours or longer and were tired. The aad confusion added to the error.
Original NASA ASRS Text
Title: FLC OF LGT ON ILS APCH DSNDS BELOW THE PUBLISHED ALT. A LOW ALT ALERT RESULTS.
Narrative: ON AN ILS APCH TO PHL WE WERE CLRED FOR THE RWY 9R APCH, I SET THE AAD FOR 2000 FT. WHEN WE WERE INSIDE 14 DME I SET THE AAD FOR 1800 FT (OUR PROC). THE CAPT RESET THE AAD TO 3100 FT. THIS CONFUSED ME SO I LOOKED AT THE APCH PLATE TO MAKE SURE WHAT I HAD DONE WAS CORRECT. WE WERE INSIDE 13 DME SO I RESET THE AAD TO 1800 FT. THE CAPT THEN TOLD ME HE DID NOT WANT TO HEAR THE AAD TONE GO OFF SO HE RESET THE AAD TO 3100 FT. ALL THIS TIME HE WAS DSNDING. I SHOULD HAVE CAUGHT HIS DSNDING BUT I DID NOT. AT THIS SAME TIME WE WERE HANDED OFF TO PHL TWR. THEY MUST HAVE TRIED TO CALL US THE SAME TIME I WAS CALLING THEM. THEY TOLD US THEY HAD A LOW ALT WARNING. THIS WAS THE FIRST TIME I NOTICED HOW LOW WE WERE. THE CAPT STARTED CLBING (WE WERE 1400 FT AGL). I TOLD HIM TO INCREASE HIS CLB RATE AND HE DID. WE WERE AT 1800 FT AT THE OM. WE HAD BOTH BEEN ON DUTY FOR ABOUT 12 HRS OR LONGER AND WERE TIRED. THE AAD CONFUSION ADDED TO THE ERROR.
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.