Timing an ILS Approach or Not?

^^^ that's friggin' amazing, man. Thanks for sharing that.
 
#2 - The threshold lights are an element of the runway environment (defined in 91.175, so further descent is permissible), provided that you have the minimum visibility for the approach, and are in a position to descend to a landing using "normal procedures," If you arrive at the approach end of the runway at 100' and would have to force the airplane down to land on the available runway or risk an over-run, then it would be advisable to execute the missed approach. If you are 100' above the TDZE and have, say a mile of visibility, to the threshold and can safely land with a normal descent rate and maneuvers, then it would be permissible to land. As a side-bar, I haven't timed $h!t from an FAF since I got my IFR rating in 2004.
 
#2...the threshold lights allow descent to 100' above TDZE. If you have the visibility, and can land with a normal rate of descent, then you can proceed to a landing. However, it you find yourself 100' above TDZE at the threshold and would have to force the plane down and/or risk an over-run, then you's best go missed.
 
Threshold lights allow you TO LAND. The threshold lights are as good as seeing the runway as far as the regs are concerned. The DA/MDA/100' stuff only applies to approach lights (and their terminating bars).
 
flyingron said:
Threshold lights allow you TO LAND. The threshold lights are as good as seeing the runway as far as the regs are concerned. The DA/MDA/100' stuff only applies to approach lights (and their terminating bars).
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Of course having seen an approach where one actually needs that extra 100' down, it's cutting things really really thin to worry about terminating bars vs threshold lights.

That last 100' happens pretty fast and you really need to go around right-frickin-now if what you're seeing 100' above the touchdown zone isn't looking good. You're down where you're going to start playing with light poles and other structures up close and personal if you screw anything up that that point.

Thankfully with so little IMC out here, I got to see that in the fog with @jesse during training and another one which was almost that low, and there's really no time to be screwing around down there.

See approach lights, okay... you get 100' more... but don't be dallying if it doesn't improve. If the runway doesn't appear... Get up and out. Now.

And don't be farting around going below 100', be ready with that throttle.

And if you go missed and things THEN appear, unless you're literally out of gas, don't try it. Go missed.

It happens quick. If you're single pilot, I joke that you get about "two looks", one at 150' and one right before 100' and you either land or go. Not much time for anything else.

And in your head, you're really planning to go missed. The runway showing up is a tiny welcome surprise and you transition to landing immediately.

And in those kind of conditions, it might disappear again before you land. You're still prepped mentally to go missed.

I really appreciated that experience in very controlled conditions. (River fog, all surrounding airports were severe clear and VFR.) It showed a little bit of how silly that reg is, single-pilot, in many ways.

You might not even really want to avail yourself of that extra 100' depending on conditions of environment, aircraft, and pilot. A whole lot of stuff can go wrong at 100' AGL in soup. Just sayin'.
 
That is dramatic. I remember when we certified the first HUD units for BA 737 and C2/C3 auto-land systems when I worked at Boeing Commercial Flight Test in the early 80's. Certainly have come a long way since then.
 
Lots of confused/twisted terminology here, which has been mostly discussed by now, but it's hard to answer the question precisely as a result.

I think a cleaned-up version of the question would be:

You're on an ILS approach to an airport whose minimums are 200' ILS approach with a published Decision Altitude of 200 feet MSL. The Touchdown Zone Elevation is 0' MSL. At approximately or above 200' 200 feet MSL, you see the threshold approach lights so you continue to descend to 100' 100 feet above the touchdown zone elevation.

I'm unable to be sure I understand what you mean here despite reading it multiple times:

Given that you do not make visual contact with the required markings/lights prescribed in 91.175(l), when do you go missed?

I think what you're getting at here is that this scenario involves being able to make out the approach lights (specifically per 91.175(c)(i)) at 200 feet MSL but unable to identify the required runway elements for landing. If that's the case you're missing a sentence to make it all come together. Did you mean this?

Upon reaching 100 feet AGL, you are unable to make out any of the visual elements listed in 91.175(c)(ii-x). Given that you do not make visual contact with the required markings/lights prescribed in 91.175(l) 91.175(c)(ii-x), when do you go missed?

If I've parsed this out correctly, then the answer is very simple. The pilot goes missed immediately upon reaching 100 feet above TDZE in that scenario, although it's hard to imagine why that would happen unless there was an obstruction on the runway, or the ATCT instructed the pilot to make an immediate go-around. If you see approach lights at DA, there's no reason you shouldn't be able to see the threshold, runway, lights, etc. a few seconds later. As it stands it's kind of a so-so hypothetical, but if the question is simply "where do I go missed?" the answer is "immediately upon reaching 100 feet above TDZE and being unable to acquire the visual references required by 91.175(c)(ii-x)."
 
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Sluggo63 said:
Just for demonstration, I took a couple of pictures through the HUD last night. EVS on and off.
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I like it mostly on the ground in low-vis taxi situations, too. It's only marginally useful in flight, in my experience, because it really can't see through clouds. But it has been handy here and there.
 
... and yes, I just realized I answered a 3+ year old question because I didn't bother checking the date. <smacks forehead>
 
Ryan F. said:
Lots of confused/twisted terminology here, which has been mostly discussed by now, but it's hard to answer the question precisely as a result.

I think a cleaned-up version of the question would be:

You're on an ILS approach to an airport whose minimums are 200' ILS approach with a published Decision Altitude of 200 feet MSL. The Touchdown Zone Elevation is 0' MSL. At approximately or above 200' 200 feet MSL, you see the lights of the threshold red terminating bars or the red side row bars are distinctly visible and identifiable, so you continue to descend to 100' 100 feet above the touchdown zone elevation.

I'm unable to be sure I understand what you mean here despite reading it multiple times:

Given that you do not make visual contact with the required markings/lights prescribed in 91.175(l), when do you go missed?
Click to expand...

Even with your corrections, the post makes no more sense than the original. The red terminating bars, just as the threshold lights, are sufficient to go ahead and land. The only way this question makes sense is if this reads "you see the approach lights, but not the red terminating bars" and you continue to 100 feet...
 
You're 100% correct. I quoted the wrong part of the regulation. I'll correct the post.
 
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