Originally Posted by
Capn Bloggs
Aterpster, I think I read somewhere that they didn't have GPS. Is the Airbus non-GPS RNAV system so accurate that it would be "perfectly aligned"? Further, I doubt their SOP would have allowed autoflight, in LNAV, down to 100ft, especially at night.
They didn't have GPS. When the lead carrier flight inspected the procedure before it was approved, they did it with and without GPS. The DME/DME environment on the entire approach was very good.
So, yes, a D/D/I airplane should be in as good as shape as a GPS/I airplane. 100 feet was to make a point. The rollout on final is at F101D at 1,200 msl. 3.5 miles from the AER. And, keep in mind this procedure is approved for IMC to as low as 1,000 and 3 with or without GPS provided:
SFO Ceiling 1000' - VIS 3 With VIS 5 in Eastern Quadrant (030^ Clockwise 120^) and San Mateo AWOS Ceiling 2400' - VIS 5 [San Mateo AWOS info available from SFO Tower. If San Mateo AWOS inop, use San Carlos (KSQL) ceiling of 2400'-VIS 5; San Carlos ATIS on 125.9]