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Reporter states that when DC10, B747 type freighters roll to the end of runway 4R and turn sideways exiting the runway, the localizer is deflected to the left for a short period of time. Reporter had previously been on an autoplt coupled approach and got a hard left turn to chase the localizer.
| Attributes | |
| ACN | 377764 |
| Time | |
| Date | 199708 |
| Day | Mon |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : ord |
| State Reference | IL |
| Altitude | agl bound lower : 600 agl bound upper : 600 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tower : ord |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent : approach |
| Route In Use | arrival other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground other : taxi |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 377764 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | none taken : unable |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Navigational Facility |
| Air Traffic Incident | other |
| Situations | |
| ATC Facility | other physical facility |
Narrative:
I was expecting this to happen last night since I've experienced this very thing before on this runway. Following a DC10 on runway 4R at ord, with instructions to roll to the end. When the preceding widebody transport aircraft rolls to the end of runway 4R and turns sideways exiting the runway, it deflects the localizer to the left about 1/2 DOT for a short period of time. Last night it was a DC10, I've experienced the same thing following a B747. Maybe it has to do with the fact that these aircraft were freighters and their fuselages were full of freight which might block the localizer beam more than a passenger aircraft would. We should get this ILS flight tested with a widebody transport aircraft blocking the localizer as if it was turning off at the end. I'm sure the result will be that the localizer is deflected significantly to the left. Last night I was hand- flying with the runway in sight so I just watched the localizer swing to the left and then come back. In the previous incident the autoplt was coupled in VMC and I got a hard left turn to chase the localizer -- not fun.
Original NASA ASRS Text
Title: RPTR STATES THAT WHEN DC10, B747 TYPE FREIGHTERS ROLL TO THE END OF RWY 4R AND TURN SIDEWAYS EXITING THE RWY, THE LOC IS DEFLECTED TO THE L FOR A SHORT PERIOD OF TIME. RPTR HAD PREVIOUSLY BEEN ON AN AUTOPLT COUPLED APCH AND GOT A HARD L TURN TO CHASE THE LOC.
Narrative: I WAS EXPECTING THIS TO HAPPEN LAST NIGHT SINCE I'VE EXPERIENCED THIS VERY THING BEFORE ON THIS RWY. FOLLOWING A DC10 ON RWY 4R AT ORD, WITH INSTRUCTIONS TO ROLL TO THE END. WHEN THE PRECEDING WDB ACFT ROLLS TO THE END OF RWY 4R AND TURNS SIDEWAYS EXITING THE RWY, IT DEFLECTS THE LOC TO THE L ABOUT 1/2 DOT FOR A SHORT PERIOD OF TIME. LAST NIGHT IT WAS A DC10, I'VE EXPERIENCED THE SAME THING FOLLOWING A B747. MAYBE IT HAS TO DO WITH THE FACT THAT THESE ACFT WERE FREIGHTERS AND THEIR FUSELAGES WERE FULL OF FREIGHT WHICH MIGHT BLOCK THE LOC BEAM MORE THAN A PAX ACFT WOULD. WE SHOULD GET THIS ILS FLT TESTED WITH A WDB ACFT BLOCKING THE LOC AS IF IT WAS TURNING OFF AT THE END. I'M SURE THE RESULT WILL BE THAT THE LOC IS DEFLECTED SIGNIFICANTLY TO THE L. LAST NIGHT I WAS HAND- FLYING WITH THE RWY IN SIGHT SO I JUST WATCHED THE LOC SWING TO THE L AND THEN COME BACK. IN THE PREVIOUS INCIDENT THE AUTOPLT WAS COUPLED IN VMC AND I GOT A HARD L TURN TO CHASE THE LOC -- NOT FUN.
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.