Narrative:

We were on the ziggy 3 arrival at ont, cleared down to 4000 ft to intercept runway 26L localizer and cleared for the approach, went through GS descending to 4000 ft, on localizer descended to 2800 ft inside petis. This was a typical slam dunk approach at ont trying to slow down and go down at the same time. Visibility was low due to fires on the hills east of ont and the usual smog, haze in the los angeles basin. Visibility was at most 4 mi. The GS came off of top of scale, it showed us constantly 2 dots low. Finally we saw runway, we were too high to make landing. We asked 360 degree turn/descent from ont tower, we were in final landing confign, flaps 25 degrees gear down, and weighed 545000 pounds (maximum landing weight), with the 360 degree turn and descent completed and established on the visual approach to runway 26L. At approximately 200 ft AGL, we noticed a helicopter had taken off and was crossing our flight path left to right at our altitude and heading towards us at a 45 degree angle. We executed a maximum bank/power/climbing turn to avoid the potential midair. (A normal go around didn't seem appropriate as our wake and thrust wash could have potentially downed the helicopter had we flown right over him.) we re-established on final for runway 26L and landed. The tower controller apologized for the conflict. He felt it was his doing. He also told us there had been several gars recently but nobody had mentioned the GS error. A B747 should not have to make maximum climbs and bank turns at 200 ft AGL unless they are in an airshow. None was scheduled for that day, we checked the NOTAMS again when we landed.

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Original NASA ASRS Text

Title: B747 CREW INBOUND TO ONT COMPLETING A 360 DEG TURN ON FINAL BECAUSE OF ALT TOOK EVASIVE ACTION AT 200 FT TO AVOID A HELI XING THE APCH END OF THE RWY.

Narrative: WE WERE ON THE ZIGGY 3 ARR AT ONT, CLRED DOWN TO 4000 FT TO INTERCEPT RWY 26L LOC AND CLRED FOR THE APCH, WENT THROUGH GS DSNDING TO 4000 FT, ON LOC DSNDED TO 2800 FT INSIDE PETIS. THIS WAS A TYPICAL SLAM DUNK APCH AT ONT TRYING TO SLOW DOWN AND GO DOWN AT THE SAME TIME. VISIBILITY WAS LOW DUE TO FIRES ON THE HILLS E OF ONT AND THE USUAL SMOG, HAZE IN THE LOS ANGELES BASIN. VISIBILITY WAS AT MOST 4 MI. THE GS CAME OFF OF TOP OF SCALE, IT SHOWED US CONSTANTLY 2 DOTS LOW. FINALLY WE SAW RWY, WE WERE TOO HIGH TO MAKE LNDG. WE ASKED 360 DEG TURN/DSCNT FROM ONT TWR, WE WERE IN FINAL LNDG CONFIGN, FLAPS 25 DEGS GEAR DOWN, AND WEIGHED 545000 LBS (MAX LNDG WT), WITH THE 360 DEG TURN AND DSCNT COMPLETED AND ESTABLISHED ON THE VISUAL APCH TO RWY 26L. AT APPROX 200 FT AGL, WE NOTICED A HELI HAD TAKEN OFF AND WAS XING OUR FLT PATH L TO R AT OUR ALT AND HDG TOWARDS US AT A 45 DEG ANGLE. WE EXECUTED A MAX BANK/PWR/CLBING TURN TO AVOID THE POTENTIAL MIDAIR. (A NORMAL GAR DIDN'T SEEM APPROPRIATE AS OUR WAKE AND THRUST WASH COULD HAVE POTENTIALLY DOWNED THE HELI HAD WE FLOWN RIGHT OVER HIM.) WE RE-ESTABLISHED ON FINAL FOR RWY 26L AND LANDED. THE TWR CTLR APOLOGIZED FOR THE CONFLICT. HE FELT IT WAS HIS DOING. HE ALSO TOLD US THERE HAD BEEN SEVERAL GARS RECENTLY BUT NOBODY HAD MENTIONED THE GS ERROR. A B747 SHOULD NOT HAVE TO MAKE MAX CLBS AND BANK TURNS AT 200 FT AGL UNLESS THEY ARE IN AN AIRSHOW. NONE WAS SCHEDULED FOR THAT DAY, WE CHKED THE NOTAMS AGAIN WHEN WE LANDED.

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.