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Old 07-01-2014, 03:50 AM   #811
Scooby Newbie
Member#: 30640
Join Date: Dec 2002
Location: on someone else's vacation
2013 WRX 5dr


You can do an autoland on a CAT1 signal, it may not be too pretty though (since glidepath/localizer antennae margins are not respected and can scallop the signal).

During that time at SFO the ILS and PAPIs (visual glidepath aids) were offline so arrivals were flying raw data visuals. That said, they would still have had a distance to touchdown generated by on board sources (gps/ins) and that is all your really need to cobble together some basic backup figures for a visual approach. Rule of thumb is your altitude should be 3x the distance plus a hundred feet (ie: for 5 miles: 53=15 hundred feet plus a hundred =1600'). Another one for vertical speed to maintain glidepath is half your groundspeed (then x10) so 200kt groundspeed should be 200/2=100 10= 1000feet per min to maintain a 3 descent path. These are basic sanity checks that you do at 15, 10, 5, 3 miles on a visual and you can see the pilot in the video never makes corrections in a way that indicates he understands how he is doing relative to the descent path he should be doing. The inappropriate FLCH mode change was just hand-over-eyes bad to watch but we've all done bonehead moves like that, esp when new on type... sometimes trying to salvage an approach isn't the best option though.
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dorikin is offline   Reply With Quote