Narrative:

We were established inbound on the runway 22R localizer at ord in VMC at 240 KTS, flaps 9 degrees, when we received our ILS runway 22R approach clearance. The first officer was the PF. We suddenly experienced a split GS with left side fly-up and right side fly-down commands. There were no flags displayed. The autoplt which was coupled to the left side pitched the aircraft down significantly, my first officer disconnected the autoplt and initiated the recovery during which the aircraft exceeded 250 KTS, flaps 9 degrees speed. A visual approach clearance was obtained and an uneventful landing followed. The left GS flag appeared below 500 ft. Altitude of incident was approximately 4000 ft. Maintenance was notified of GS problem and flap overspd. Maintenance entry was made.

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Original NASA ASRS Text

Title: EMJ FLT CREW EXPERIENCES AN ILS GS MALFUNCTION DURING A VISUAL APCH TO ORD.

Narrative: WE WERE ESTABLISHED INBOUND ON THE RWY 22R LOC AT ORD IN VMC AT 240 KTS, FLAPS 9 DEGS, WHEN WE RECEIVED OUR ILS RWY 22R APCH CLRNC. THE FO WAS THE PF. WE SUDDENLY EXPERIENCED A SPLIT GS WITH L SIDE FLY-UP AND R SIDE FLY-DOWN COMMANDS. THERE WERE NO FLAGS DISPLAYED. THE AUTOPLT WHICH WAS COUPLED TO THE L SIDE PITCHED THE ACFT DOWN SIGNIFICANTLY, MY FO DISCONNECTED THE AUTOPLT AND INITIATED THE RECOVERY DURING WHICH THE ACFT EXCEEDED 250 KTS, FLAPS 9 DEGS SPD. A VISUAL APCH CLRNC WAS OBTAINED AND AN UNEVENTFUL LNDG FOLLOWED. THE L GS FLAG APPEARED BELOW 500 FT. ALT OF INCIDENT WAS APPROX 4000 FT. MAINT WAS NOTIFIED OF GS PROB AND FLAP OVERSPD. MAINT ENTRY WAS MADE.

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.