This is not quite the same though. I am told by airline pilots that most big jets don’t fly the ILS as published i.e. level flight at the platform altitude, until LOC and then pick up the GS. They fly a long continuous descent and intercept the LOC and GS at some point within some documented range. We had some previous threads on this; there is a lot of detail involved. In some cases the GS is intercepted from above.
6nm is a long way out.
I suppose the obvious answer for “GA” is to follow the normal procedure i.e. drop the gear and Flap 1 at GS intercept, and achieve the 160kt with ample power, then reduce power at 4nm or whatever the inner speed limit expiry is. I don’t see any other way (unless you have speed brakes) which also involves flying the published procedure (obviously).
Timothy’s method is interesting but a dip below the GS will pick up speed, which you don’t want. So the whole ILS would have to be flown below the GS, which isn’t going to happen unless you are hand flying the whole thing, which most people don’t do especially when under pressure.
Peter wrote:
Timothy’s method is interesting but a dip below the GS will pick up speed, which you don’t want. So the whole ILS would have to be flown below the GS, which isn’t going to happen unless you are hand flying the whole thing, which most people don’t do especially when under pressure.
I suppose you could still fly it on AP but i/o being in GS mode you fly it in VS mode as per the plates? (edited for completeness) – Sorry that is on an STEC55
The way I am training it (I am doing the CB-IR right now) is
The gear could technically be put out earlier at VLO 130kts to help with slowing down, but SOP is to do all at once.
When trained last week I was re-configured and re-trimmed by 3.3 DME ie above 1000ft AGL (for a standard descent angle), still on the GS, all hand flown.
So much for stabilised approaches
Let’s look at some detail……….
What I believe is the standard ILS training, what I had, is: fly at Vlo (130kt for a TB20) all the way to the GS intercept, then drop gear, Flap 1. Adjust power for the desired speed. It is easy to slow down as needed further down the GS. That is the standard “GA” profile which is to get descents to the IAP platform and then intercept the LOC in level flight. This is not how big jets fly AFAIK.
If your Vlo is 160kt, then you can maintain 160kt as requested by ATC.
According to this local copy the Extra 400 Vlo is about 140kt
so I don’t see how you can do the GS intercept and fly a part of the GS at 160kt with the gear UP and then drop the gear, because losing 20kt while descending, without speed brakes, is not going to work.
Extending flaps is not going to work; they have unusually low speed limits:
So Flyingfish is consigned to flying the GS at 120kt max, unless he can do something drastic to lose 40kt at 4D or whatever, but that is way above the DA so may still be in IMC, and you don’t want to be hand flying doing sideslips or s-turns in IMC, while nominally tracking the ILS 
What am I missing?
Aviathor wrote:
So much for stabilised approachesI understood the question as “How do you do high-speed approaches when requested so by ATC?”, and this is what I described in my post above. A normal approach is much less dramatic and stabilized long before.
In our line of business when operating the DA62, we fly clean to Decision Altitude at up to 200kts and take things from there. At times, I will keep 200kts to threshold, especially if I’m aiming for a fast exit some 7000ft down the runway.
HOWEVER, we’re used to doing that sort of profile and more (190kts down the length of the runway at 12ft).
Answering the OP question, most airports only insist on 160-to-4 and I think most SEPs are capable of managing energy between 4 and DA/DH which, personally, I think is the point where you decide to add the last bit of drag. I’m not a fan of flying alternative glide slopes.
a dip below the GS will pick up speed
That is the point. You use the dip to increase speed then lose the momentum in the climb.
Standing on one’s high horse and saying “ATC has a duty…” will only result in more bannings from big airports, probably for all of us except Jason, so that is not the best approach.
I agree with Dave that messing with the glidepath is not ideal, but equally there is no way that an aircraft as described can do a stabilised approach. Stabilisation means in speed, configuration and RoD, and one or more of those is clearly out of the window, so we have to determine which element of stability we are going to sacrifice (unless we decide to sacrifice the ability to take little aeroplanes into big airports.)
All I am saying is that I have done literally hundreds of “160 (or even 180) knots to 4nm” in aircraft with a gear speed of 130kts and I have tried all sorts of ways of dealing with it, without risking the engines, and converting kinetic energy into potential, putting out the washing at its limits, works best for me.
I assume that the DA62 has a gear speed of Vne, like the 42, in which case there is no problem. Similarly the Chieftain is 152 kts and also not much of a problem, but speeds of 120-130 have to be dealt with somehow.
Peter wrote:
losing 20kt while descending, without speed brakes, is not going to work.It works just fine on a draggy tin-can like a Warrior or Arrow, just remove power. The Extra is probably more slippery though.
The DA42/62 have no problem to slow down. You just cut the power and the two propeller disks will act as speedbrakes, and they also have a very high Vlo.
My current ride has Vfe of 127 and 117 KIAS, but starting down at 160 KIAS and 800 fpm I have little chance of slowing down below 127 KIAS by 4 NM unless I use speedbrakes. And use of speedbrakes requires a big pitch (up) change in order to remain on the glideslope, and another pitch (down) change when retracting. Not something I fancy to do in IMC. And I have no gear to extend.
Until now, with the Columbia I have not been to any airport with such speed requirements. But just like Flyingfish, I know I need to get this figured out before I am forced to do so somewhere.
