16-01-2006, 03:56 AM
Over the years I have noted that most large aircraft maintain 120-140 (scopes only show the 12-14 so it could be 120 or 129,) on final inside the FAF
to touchdown. We also on occasion conduct what is called an ASR approach which is like a radar guided LOC approach without the LOC. In any case, we
try to match up with a 3* descent which works out to about 300 feet per mile. If you figure that you're travelling a little over 2 miles per minute
you can pick a point on the approach, do the math, and plot out where you need to start your descent with a rate of 700 fpm. I did this today
actually when I was assigned a VIS approach into KBOI RY28L. Looking in my approach plates I saw that 28L has a BC approach and thought why not try
this. I used the BC function on the autopilot and programmed the altitude hold to lvl out 200' agl, (3100 msl.) It would have worked perfectly if I
hadn't of started down a mile late. As it was, I landed long but didn't have to go around. FYI: I was flying a Boeing 733 on this flight. Give this
a go, I think you'll find it works well, just remember to give yourself the 1-200 foot buffer to lvl out, flair and touchdown.
to touchdown. We also on occasion conduct what is called an ASR approach which is like a radar guided LOC approach without the LOC. In any case, we
try to match up with a 3* descent which works out to about 300 feet per mile. If you figure that you're travelling a little over 2 miles per minute
you can pick a point on the approach, do the math, and plot out where you need to start your descent with a rate of 700 fpm. I did this today
actually when I was assigned a VIS approach into KBOI RY28L. Looking in my approach plates I saw that 28L has a BC approach and thought why not try
this. I used the BC function on the autopilot and programmed the altitude hold to lvl out 200' agl, (3100 msl.) It would have worked perfectly if I
hadn't of started down a mile late. As it was, I landed long but didn't have to go around. FYI: I was flying a Boeing 733 on this flight. Give this
a go, I think you'll find it works well, just remember to give yourself the 1-200 foot buffer to lvl out, flair and touchdown.

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