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DC10 captain descended below the MSA during a visual approach due to the night lighting conditions caused him to believe that he was at the appropriate altitude during his 8 mi visual approach.
| Attributes | |
| ACN | 512232 |
| Time | |
| Date | 200105 |
| Day | Fri |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : iah.airport |
| State Reference | TX |
| Altitude | agl single value : 1200 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Thunderstorm |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tower : iah.tower |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Route In Use | approach : visual |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : commercial pilot : atp pilot : multi engine pilot : instrument |
| Experience | flight time last 90 days : 20 flight time total : 11000 flight time type : 1500 |
| ASRS Report | 512232 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | other anomaly other other spatial deviation |
| Independent Detector | atc equipment : msaw other controllera |
| Resolutory Action | controller : issued alert flight crew : became reoriented flight crew : took precautionary avoidance action |
| Supplementary | |
| Problem Areas | Weather Environmental Factor Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Arrived in the terminal area and was vectored for an ILS runway 26. Discontinued approach due to thunderstorms on final approach, accepted delay vectors, then was advised runway 33R was available. While entering approach into the FMS (first officer flying), approach control asked if we had a visual on the airport. Runway was in sight about 8 mi and we were cleared for a visual approach, ILS to runway 33R not working (no electronic GS). Runway 33R has no VASI, PAPI, etc. We appeared to be on a 'normal sight picture' for a visual approach when tower advised of a low altitude alert. I leveled off the descent rate, recomputed a distance to runway versus radar altitude, then resumed a corrected visual glide path to the runway. Vectoring in the local area, WX avoidance, loading multiple approachs in the FMS (ILS runway 26, then ILS runway 33, then VOR 33) and ATC communications led to 'task saturation' and a visual descent point which began slightly earlier than desired. Also, the 'dark ground' between our aircraft and the runway produced the illusion of being higher than required for the optimum visual glide path. From handoff from approach to touchdown (with tower) flight conditions were night VMC, visibility approximately 8+ NM.
Original NASA ASRS Text
Title: DC10 CAPT DSNDED BELOW THE MSA DURING A VISUAL APCH DUE TO THE NIGHT LIGHTING CONDITIONS CAUSED HIM TO BELIEVE THAT HE WAS AT THE APPROPRIATE ALT DURING HIS 8 MI VISUAL APCH.
Narrative: ARRIVED IN THE TERMINAL AREA AND WAS VECTORED FOR AN ILS RWY 26. DISCONTINUED APCH DUE TO TSTMS ON FINAL APCH, ACCEPTED DELAY VECTORS, THEN WAS ADVISED RWY 33R WAS AVAILABLE. WHILE ENTERING APCH INTO THE FMS (FO FLYING), APCH CTL ASKED IF WE HAD A VISUAL ON THE ARPT. RWY WAS IN SIGHT ABOUT 8 MI AND WE WERE CLRED FOR A VISUAL APCH, ILS TO RWY 33R NOT WORKING (NO ELECTRONIC GS). RWY 33R HAS NO VASI, PAPI, ETC. WE APPEARED TO BE ON A 'NORMAL SIGHT PICTURE' FOR A VISUAL APCH WHEN TWR ADVISED OF A LOW ALT ALERT. I LEVELED OFF THE DSCNT RATE, RECOMPUTED A DISTANCE TO RWY VERSUS RADAR ALT, THEN RESUMED A CORRECTED VISUAL GLIDE PATH TO THE RWY. VECTORING IN THE LCL AREA, WX AVOIDANCE, LOADING MULTIPLE APCHS IN THE FMS (ILS RWY 26, THEN ILS RWY 33, THEN VOR 33) AND ATC COMS LED TO 'TASK SATURATION' AND A VISUAL DSCNT POINT WHICH BEGAN SLIGHTLY EARLIER THAN DESIRED. ALSO, THE 'DARK GND' BTWN OUR ACFT AND THE RWY PRODUCED THE ILLUSION OF BEING HIGHER THAN REQUIRED FOR THE OPTIMUM VISUAL GLIDE PATH. FROM HDOF FROM APCH TO TOUCHDOWN (WITH TWR) FLT CONDITIONS WERE NIGHT VMC, VISIBILITY APPROX 8+ NM.
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.