Three Approaches in IFR/LIFR, Visionjet Demo. LIFL returns!

Jon, I actually had to pause watching when you were calculating your potential max altitude for glidepath intercept crossing CACAS into JYO at the beginning. Couldn't figure out the HAT part. Why not just apply the 300 FPNM rule of thumb to the 7 miles between CACAS and DANMO to say that you expect to intercept the glidepath at CACAS at 4200? (And yes, I'd want a buffer)

After wondering, returned to the video and loved it!
 
midlifeflyer said:
Why not just apply the 300 FPNM rule of thumb to the 7 miles between CACAS and DANMO to say that you expect to intercept the glidepath at CACAS at 4200? (And yes, I'd want a buffer)!
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GREAT question. First, as a general matter, I find math in the cockpit difficult. Am I the only one? Simple stuff that I can do in my sleep on the ground becomes a struggle when Im flying solo IFR in IMC. Second, your approach is exactly correct and I confess I hadn't thought of that! In other words, why measure the distance from the IAF/IF to the MAP as the multiplier and instead just measure the distance from the FAF to the IAF/IF and use that? I guess I've always done it my way as force of habit and because it makes me reckon with the overall length of the approach. However, I am going to try it your way next time for sure. THANK YOU!
 
Jon Weiswasser said:
GREAT question. First, as a general matter, I find math in the cockpit difficult. Am I the only one? Simple stuff that I can do in my sleep on the ground becomes a struggle when Im flying solo IFR in IMC. Second, your approach is exactly correct and I confess I hadn't thought of that! In other words, why measure the distance from the IAF/IF to the MAP as the multiplier and instead just measure the distance from the FAF to the IAF/IF and use that? I guess I've always done it my way as force of habit and because it makes me reckon with the overall length of the approach. However, I am going to try it your way next time for sure. THANK YOU!
Click to expand...
You are not alone. Heck, GPS was a godsend for me just so I didn't have to use my fingers and toes to count the degrees to turn for partial panel! That's why I mentioned it. I think it's a much easier calculation.

Actually, I usually don't consider it at all :D So far, I've never been given a transition or IF altitude which was so much higher than the minimum for the fix that I was even concerned about being above the glidepath. I realize that "normal" is different for different aircraft, but ATC is supposed to "Assign an altitude ... that will permit a normal descent to the FAF." And it goes on to say that "Controllers should expect aircraft to descend at approximately 150-300 feet per nautical mile ..." Basically no more than a 3°descent.

So, all I do is look for the glidepath when the FAF becomes the active waypoint. If it's above me (it always has been), I hold altitude until intercept. If it turned out to be below me, I'd head down toward intercept altitude at a good rate until I caught up. If I got a crossing altitude which really seemed out of whack, I'd activate the leg to the FAF to make the glidepath come in early.
 
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Another great video. Thank you!
 
“... First, as a general matter, I find math in the cockpit difficult. Am I the only one? ...”

BWAHAHAHAHA BWAHAHAHAHA BWAHAHAHAHA

Hey guys, looky what he asked! BWAHAHAHAHA
BWWWWAHAHAHAHA BWWWWWWAHAHAHAHA

Uh no. You’re NOT the only one. I can do a mathematical proof of the quadratic equation using the complete the square method... in a cockpit, if it ain’t divisible by 6, easily, I’m done. DONE.

In the Navy we would choose air speeds and fuel flows specifically to make the public math easier. 360 kts on a low level. Fuel flow of 3600 lbs/hr. Etc. At idle on a bingo descent the jet burned 900 lbs/hr, that was problematic...
 
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