ILS question

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wind_shear

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on an ILS after reaching DA and having all the required items to descend below DA do you still fly the GS and LOC all the way to the runway or use the VASI/PAPI if available?
 
Once you have visually secured the runway environment and passed the DA, then you are by definition visual. You could still make secondary reference to your in-cockpit guidance, but your head should be out the window using the runway itself and its lighting systems.

* Orest
 
If you have the runway in sight upon reaching DA, than it essentially just becomes visual at that point.
 
I'm not IFR rated but if I understand the lingo and the question ...

DA is for decision altitude ... so make a decision! :p
 
If you descending to 100' above TDZ in accordance with 91.175(c)(3)(i), you don't yet have enough visual references to land so the aircraft attitude, LOC, and GS should be carefully monitored until you do have enough visual reference to complete the landing visually.
 
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wind_shear said:
on an ILS after reaching DA and having all the required items to descend below DA do you still fly the GS and LOC all the way to the runway or use the VASI/PAPI if available?
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You could meet the requirements to descend below the DA before getting the VASI/PAPI in sight. Paying attention to the needles is probably a good idea until you do. Once acquiring the VASI/PAPI keeping your eyes outside is not a bad idea

EDIT: :yeahthat:
 
Both. Keep monitoring the LOC/GS and make your transition to the outside. Even though you have the VASI/PAPI in sight, if you’re shooting an approach down mins at 1/2 mile vis it’s a good idea to stay on your instruments in case you lose the runway or get disoriented.
 
wind_shear said:
on an ILS after reaching DA and having all the required items to descend below DA do you still fly the GS and LOC all the way to the runway or use the VASI/PAPI if available?
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Once you have the runway in sight, eyes outside and adjust for the landing visually. Whether that be vasi/papi, or pick your landing spot.
 
Rick Durden wrote an article about this exact topic:

https://www.avweb.com/flight-safety/technique/the-last-400-feet/

Not sure I agree: if I have good visual contact with the runway after breaking out, I don't want to cross the threshold in my PA-28 at 90 knots or 110 knots or whatever my approach speed was, even if I do have a 10,000 foot runway ahead of me. But still, lots of good points.
 
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Larry in TN said:
If you descending to 100' above TDZ in accordance with 91.175(c)(i), you don't yet have enough visual references to land so the aircraft attitude, LOC, and GS should be carefully monitored until you do have enough visual reference to complete the landing visually.
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I think you mean 91.175(c)(3)(i).
 
wind_shear said:
on an ILS after reaching DA and having all the required items to descend below DA do you still fly the GS and LOC all the way to the runway or use the VASI/PAPI if available?
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On an IFR flight in VMC, do you look outside, or do you use the instruments to maintain level flight?
 
One thing to consider is that the ILS may not be certified below your standard mins (cat II and III being exceptions).

That being said, I follow them further.

In a sim I take them to the flare because visuals aren’t great (even the really good ones).

I’ve seen plenty of ILSs not jive well with visual glide path indicators.
 
One call out maybe baked into this thread is this:

Approach plates are to guide you down to a position where you should be able to make a successful landing visually.

That’s it.

I think there is a belief that IAPs are to guide you all the way down to the runway but in reality they guide you to a point in space, which given a category of aircraft, should be in an acceptable position to land visually.

That’s why in-flight visibility requirements are part of every approach’s minima.
 
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The goal of flying the approach is to get you at the right speed and direction so that when you get low enough to see the runway you can land. If you can't see the runway at DA, you go missed. So yes, you land visually. The PAPI and the glide slope in the plane should be in alignment BTW.
 
Trogdor said:
That’s why in-flight visibility requirements are part of every approach’s minima.
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I've flown ILS Cat3 approaches where the mains touched about 3 seconds after I picked up the runway CL lights.
 
Greg Bockelman said:
Being on an IFR flight plan does not absolve you of the responsibility to maintain a lookout for any other traffic, VFR or IFR when in VMC.
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That was my point. Why would you fly the LOC/GS when you have the runway in sight?
 
sarangan said:
That was my point. Why would you fly the LOC/GS when you have the runway in sight?
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Oh, stuff like guaranteed obstacle clearance in low viz or night conditions. Continued lateral guidance to ensure it's the correct runway and not a parallel runway or taxiway you see. Standard set of visual illusions which makes us see ourselves higher than we are and have led pilots to dive into the ground short of the runway. 1/2 mile viz is not severe clear and can change back to zero in a flash.

I guess there are some pro and con arguments on this one, but none I can see giving a good reason splitting attention between instruments and outside when flying instruments is a bad SOP. If you didn't, how would you know you broke out?
 
sarangan said:
That was my point. Why would you fly the LOC/GS when you have the runway in sight?
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You should never be fixated CDI or HSI, because they're not primary control instruments — you pick an attitude, heading, and power setting, and then just glance at the CDI occasionally to see if they're keeping you on the LOC and GS.

In IMC, you're using the attitude indicator; in VMC, you're looking out the window to maintain attitude. But the rest is the same.
 
Tools said:
One thing to consider is that the ILS may not be certified below your standard mins (cat II and III being exceptions).

That being said, I follow them further.

In a sim I take them to the flare because visuals aren’t great (even the really good ones).

I’ve seen plenty of ILSs not jive well with visual glide path indicators.
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And there are many, many Approach Charts that tell you just that.
 
David Megginson said:
You should never be fixated CDI or HSI, because they're not primary control instruments — you pick an attitude, heading, and power setting, and then just glance at the CDI occasionally to see if they're keeping you on the LOC and GS.

In IMC, you're using the attitude indicator; in VMC, you're looking out the window to maintain attitude. But the rest is the same.
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I agree with you about not being fixated - on anything. I don't know what definitions you are using for "primary" and "control" (i.e., the formal definitions of the two main methods of instrument interpretation or something more generic), but I can't agree that the CDI/VDI isn't "primary" for maintenance of lateral and vertical course guidance on a approach, particularly since not prioritizing those is one of the most common errors I see.
 
midlifeflyer said:
I agree with you about not being fixated - on anything. I don't know what definitions you are using for "primary" and "control" (i.e., the formal definitions of the two main methods of instrument interpretation or something more generic), but I can't agree that the CDI/VDI isn't "primary" for maintenance of lateral and vertical course guidance on a approach, particularly since not prioritizing those is one of the most common errors I see.
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The AI is a control instrument — you use it to decide where to move the controls. The CDI is a monitoring instrument: you use it to see if the attitude and power you've chosen are giving you the result you want, but you (should) never chase the needles by moving the controls while looking at the CDI. If you're high on the glideslope, then you go back and adjust your pitch and power (using AI and MP/RPM as primary), then take another glance to see if they've put you where you need to be.

The point of all this is that there should not be a big difference staying on the LOC and GS whether you're in IMC or VMC. In IMC, you're scanning your primary control instruments most of the time, and just occasionally glancing at the CDI to see if your chosen attitude and power are putting you in the right place; in VMC, you're looking out the window most of the time, and just occasionally glancing at the CDI to see if your chosen attitude andpower are putting you in the right place. If it seems like a big deal both scanning outside the window and staying on the ILS after you break out, then you're probably fixating on the CDI while you're in real or simulated IMC (something I used to do, and had to work hard to get over).

Another symptom of chasing the needles is that it becomes increasingly difficult to keep them centred as you get closer and the tolerances become tighter. You can get away with chasing the needles at 5 miles final over the FAF, because the lag isn't enough to keep you from very gentle (barely noticeable) oscillation up and down and side to side; at 1 mile final or closer, you'll really struggle to stay on the LOC and GS if you're chasing them instead of flying by attitude, heading, and power, because you'll always be a second or two behind them, and they'll be dancing up-and-down and side-to-side as you make increasingly abrupt control movements trying in vain to catch up.
 
David Megginson said:
The AI is a control instrument — you use it to decide where to move the controls. The CDI is a monitoring instrument: you use it to see if the attitude and power you've chosen are giving you the result you want, but you (should) never chase the needles by moving the controls while looking at the CDI. If you're high on the glideslope, then you go back and adjust your pitch and power (using AI and MP/RPM as primary), then take another glance to see if they've put you where you need to be.
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I agree with never chasing a needle. But making a 2-3 degree turn on the AI because you detected a small movement of the CDI does not equal chasing any more than you are visually chasing a gusting crosswind when you make small corrections to maintain centerline during a visual landing. What I often see in practice is a failure to prioritize the CDI/VDI (actually to recognize that scan priorities can change with phase of flight) in a way that deviations are not caught and corrected immediately. That leads to larger deviations, which in turn leads to overcorrections. Its fun to watch a pilot hold heading and attitude perfectly while the CDI slides slowly but continuously to the left or right. On the other hand, it's just as much fun to fly with an ATP skill level pilot and watch the needles seemingly not move at all. The needles are moving of course, but the pilot sees those movement so early (much earlier than I can on my best day) and corrects them so quickly, it's barely noticeable.
 
midlifeflyer said:
I agree with never chasing a needle. But making a 2-3 degree turn on the AI because you detected a small movement of the CDI does not equal chasing any more than you are visually chasing a gusting crosswind when you make small corrections to maintain centerline during a visual landing. What I often see in practice is a failure to prioritize the CDI/VDI (actually to recognize that scan priorities can change with phase of flight) in a way that deviations are not caught and corrected immediately. That leads to larger deviations, which in turn leads to overcorrections. Its fun to watch a pilot hold heading and attitude perfectly while the CDI slides slowly but continuously to the left or right. On the other hand, it's just as much fun to fly with an ATP skill level pilot and watch the needles seemingly not move at all. The needles are moving of course, but the pilot sees those movement so early (much earlier than I can on my best day) and corrects them so quickly, it's barely noticeable.
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Agree that the CDI still needs to be in the scan regularly — neglecting it is even worse than fixating on it. Ditto for other secondary (performance/monitoring) instruments like the ALT or ASI.
 
OK, this thread and my posts are getting misinterpreted. The OP asked if he should "still fly the GS and LOC" after the runway environment is in sight. The answer is no; not unless you are under the hood for training.
On a similar vein, I posed a rhetorical quesiton if a pilot in VMC should use the flight instruments to maintain level flight. Again, the answer is no, unless you are under the hood for training.
 
sarangan said:
OK, this thread and my posts are getting misinterpreted. The OP asked if he should "still fly the GS and LOC" after the runway environment is in sight. The answer is no; not unless you are under the hood for training.
On a similar vein, I posed a rhetorical quesiton if a pilot in VMC should use the flight instruments to maintain level flight. Again, the answer is no, unless you are under the hood for training.
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Why are the answers “no”?
 
I think the answer is "it depends". I was taught to stay on the GS and LOC even after the runway is in sight. It is possible for the field to disappear from view after you think you have it made. Being on the GS and Localizer could save your life. There are examples and reasoning for why you may be able to see a runway at altitude because you are looking down through a layer, but when you get lower your horizontal view through the layer increases and you lose the runway. There is a video of jet pilots in a larger jet, flying an approach, the runway is in plain sight, but when they get a few hundred feet above the runway, a fog bank blows in and they have to go around. It can happen.
 
Daleandee said:
I'm not IFR rated but if I understand the lingo and the question ...

DA is for decision altitude ... so make a decision! :p
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DA (Decision Altitude) is the altitude at which you decide you can go visual and land or "go missed". If you go visual, then you are VFR. If you go missed then you follow the published "missed" procedure, or whatever ATC instructs you to do.

(that is the serious explanation, even though you put a smiley on you comment denoting that you already knew that).
 
Summed up a few times already. IFR approach is to get you lined up at the right speed to get you low enough below the ceiling so that you can see to land. You land by seeing the runway. You decide if you can see the runway at the DA.

On landing your eyesight is better and more accurate than looking at the instruments. Why handicap yourself?



(Uber exotic auto land CAT 3 landing systems and whatnot aside).
 
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