ILS question

dmspilot said:
No you aren't.
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You are still under IFR rules, but you are flying in VMC. As you’re in VMC - look out the window.

IFR ends when you close the plan or cancel in the air.
 
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MauleSkinner said:
The primary control instrument is the AI. The supporting control instruments are the other five flight instruments. ;)
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That's why I asked. I didn't know if he was using it that way or some more generic way. Besides, neither Primary/Supporting nor Control/Performance are scan techniques.
 
WDD said:
You are still under IFR rules, but you are flying in VMC. As you’re in VMC - look at the window.
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The OP’s question doesn’t seem to me to be about where you look so much as where you fly.

But “VMC” technically means weather that allows VFR flight, so in the context of this discussion you probably aren’t VMC.
 
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luvflyin said:
Not necessarily VMC either. And given the conditions we’ve been discussing here, very unlikely VMC.
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Exactly. Even if you can see portions of the runway or all of it, 1/2 mile visibility is not VMC,p. Of course, if we fly an approach and break out at pattern altitude in VFR conditions, we absolutely need to get our eyes off the gauges.never mind the runway. We have VFR traffic to consider
 
True, you’re right - not VMC. ISTDR conditions.

I See The Damn Runway.

It still doesn’t change the fact that you look out the window when landing.
 
Maybe not. If I have good visual on the runway why would I divert my attention? If I loose the runway I should have gone missed before DA. If I’m below DA and the lose the runway I go missed.
 
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WDD said:
Maybe not. If I have good visual on the runway why would I divert my attention? If I loose the runway I should have gone missed before DA. If I’m below DA and the loose the runway I go missed.
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And there's nothing worse than a loose runway.
 
PaulS said:
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.
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I agree with the "it depends" part. For example, the Monterey ILS chart says "ILS unusable from 1.7 DME inbound."
 

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WDD said:
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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It depends on the circumstances. At night or in foggy weather or heavy rain/snow (you might not see the PAPI or VASI clearly in the last cases, even if there is one), following the ILS a little further down past DH — when not forbidden by a note on the approach plate — might help avoid falling victim to some deadly optical illusions, even though you have the runway in view continually. Note, too, that you don't actually have to see the runway to continue past DH with an ILS or any other approach; you just have to be able to see the approach lights leading up to the runway or the approach-slope indicator, at least under Canadian regs, and I assume, US regs as well (I've landed from an ILS after seeing only two of the approach lights leading to the runway at DH, but not the runway itself).

Also — let's be realistic — outside of training or an IPC, the vast majority of us will be flying the ILS or LPV approaches coupled to an IFR approach-certified autopilot most of the time (except when we're deliberately practicing). Obviously, don't use the autopilot below its minimum altitude AGL limitation (if there's one published), but if you're allowed to keep it engaged — at least in lateral mode — why make things harder for yourself at the highest-risk moment of an instrument approach, the transition from instruments to visual? And usually, that transition will be happening at 600–1,000 ft AGL, not right at 200 ft AGL (a real approach isn't like when you lift the foggles at DH or MDA and go from nothing to everything), so even if you have (say) a 400 ft AGL operating limitation on your A/P, you can still let it keep helping you for a while and reducing the workload. Make the most of all the resources available to you.
 
midlifeflyer said:
That's why I asked. I didn't know if he was using it that way or some more generic way. Besides, neither Primary/Supporting nor Control/Performance are scan techniques.
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Certainly they are — see, for example, page 76 of the Canadian Instrument Procedures Manual, 5th edition. Perhaps the FAA uses different jargon for the same idea.

Control Instruments
Control instruments indicate attitude of the aircraft and power (thrust/drag) being applied to the aircraft. These instruments are calibrated to permit adjustments in definite amounts. They include the attitude indicator and engine control instruments (tachometer, manifold pressure, RPM, EPR, N1, Torque).

Performance Instruments
Performance instruments indicate the actual performance of the aircraft which can be determined from the airspeed/mach indicators, turn-and-bank (or turn co-ordinator), VSI, altimeters, heading indicator, and magnetic compass.

Navigation Instruments
Navigation instruments indicate the position of the aircraft in relation to a particular navigational aid or RNAV system that has been selected. These can include NDB, VOR, ILS, GPS, INS, IRS and FMS.
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The idea is that you spend less time on the instruments as you move down the groups. The control instruments are how you actually … um … control the aircraft, so they're what you should be looking at whenever you move the controls. The performance instruments show you how you're doing, so they still deserve a fair bit of attention in the scan (e.g. you should have chosen a specific heading and vertical descent rate to keep the CDI centred, not just be chasing the needles left and right, up and down), but you look at them after you've moved the controls, to see if you got the results you hoped for (and are maintaining them). The navigation instruments like the CDI should get the least attention of the three groups, but it's still important to keep them in the scan often enough that you can make timely corrections in the first two groups, especially during an approach.

What does the FAA call these groups?
 
WDD said:
True, you’re right - not VMC. ISTDR conditions.

I See The Damn Runway.

It still doesn’t change the fact that you look out the window when landing.
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Certainly, but during the 1/2 mile to 3+ miles before that, once you've broken out, you're probably still scanning your panel (at least the ASI) in addition to looking out the window; it's just that it's more like 80:20 outside:inside now. This isn't an either-or choice.

If I break out at 800 ft and it's glorious, 3-mile visibility and bright daylight underneath, sure, I'll approach and land the same as if I were flying VFR. But we don't always have that kind of luck when we're flying IFR. Sometimes you can just sort-of make out the runway lights, or the approach lights, or else it's night and the driving rain is obscuring the approach-slope indicator. Then I'll devote a bit of my attention to the AI and CDI as well as scanning outside, and will stick with the approach path that's served me well up to that point until the runway threshold passes below my wheels (at around 50 ft AGL).
 
Sounds about right. I’m just using outside as my “primary instrument”
 
JOhnH said:
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.
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You don't need VFR weather to fly a visual approach under IFR.
 
David Megginson said:
Certainly they are — see, for example, page 76 of the Canadian Instrument Procedures Manual, 5th edition. Perhaps the FAA uses different jargon for the same idea.
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Same idea. But that's not a scan technique, it is a methodology for instrument interpretation and cross-referencing for errors. Theory. Scan techniques - radial, hub and spoke, inverted V, roll your own whatever - are implementations of those theoretical constructs.

Don't know about you but the technique I use to scan the relevant instruments changes with the phase of flight. The underlying theory of which instruments provide the most relevant information for a flight action and conflict resolution remains the same.
 
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sarangan said:
You don't need VFR weather to fly a visual approach under IFR.
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Not quite that simple. Yeah, you don’t have to comply with Cloud Clearance Requirements. But the field must be reported VFR. Ceiling 1000 or greater and Visibility 3 or more.
 
luvflyin said:
Not quite that simple. Yeah, you don’t have to comply with Cloud Clearance Requirements. But the field must be reported VFR. Ceiling 1000 or greater and Visibility 3 or more.
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Yes, very true. But I was responding to "If you go visual, then you are VFR". Below the MDA/DA you are flying visual. That doesn't mean your IFR has been cancelled and you are VFR.
 
Tools said:
I’ve seen plenty of ILSs not jive well with visual glide path indicators.
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They are two different systems and not always set to the same glidepath angles. Even when they are tolerances in both systems can make them not coincide with each other. However, both are flight check certified to guarantee obstacle clearance one dot (or light) below path. In the case of VGSI this guarantee doesn't extend out as far, but on short final either system will work. Once I'm outside, I prefer to stay outside to the maximum extent practical so I use VGSI when I have it.
 
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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VGSI and Descent angles may not be the same. Fly the ILS to DA, the follow the VGSI. The VGSI may take in to account obstacles. If both are 3 degrees, then you could use both. The other day, I flew the ILS 25R in to Livermore, CA and flew the GS all the way down. Both were 3 degrees.

The above are my views on the matter. I'm no CFII.
 
pb172 said:
The above are my views on the matter. I'm no CFII.
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Not sure if it would make a big difference if you were — a CFII isn't necessarily an authority on anything but teaching students to pass flight tests.

A lawyer specialised in aviation law, maybe, or an FAA official might be able to appeal to personal credentials to back what they're saying. But otherwise, we're all legal and regulatory laypeople here, whether we fly for fun or fly for money, and any credibility comes from the sources we cite rather than who we are.
 
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David Megginson said:
A lawyer specialised in aviation law ... might be able to appeal to personal credentials
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I wouldn't believe a lawyer who did that in a public forum.

any credibility comes from the sources we cite rather than who we are
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One can only hope.
 
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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Be aware that on a CAT I ILS, that is not used below 200' DA, the glide slope is required to meet FAA flight inspection tolerances (refer to FAA Order 8200.1) between "ILS Point C" (about 925' prior to the RWY THLD) to 10 NM from the THLD. In the 925' between "ILS Point C" and the THLD, the glide slope is not required to meet tolerances. "ILS Point C" is the point thru which the glide slope passes at a point 100' above the RWY THLD. This means that glide slope "Clearances", which give you positive fly-up or positive fly-down may not be available and/or there could be a course reversal in this area. Following the glide slope after "ILS Point C" on this type ILS facility may be undesirable.

On all CAT I (used below 200' DH), CAT II and CAT III facilities, the glide slope must meet the appropriate tolerances from 10 NM to the RWY THLD. Following the glide slope from "ILS Point C" to the THLD on these unrestricted facilities will provide the desired guidance.
 
WDD said:
You are still under IFR rules, but you are flying in VMC. As you’re in VMC - look out the window.

IFR ends when you close the plan or cancel in the air.
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I breakout on an ILS in Class B,C,D,E or G airspace with <1 sm flight visibility. How am I VMC?
 
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Clip4 said:
I breakout on an ILS in Class B,C,D,E or G airspace with <1 sm flight visibility. How am I VMC?
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I think what he really means is once you hit DA and have the run-way environment insight, you go visual. In fact, *every* successful approach ends that way since an IAP puts you in a position to land visually (for now assume success means not going missed).

What’s interesting is that no matter what approach you shoot, you land visually (no duh!). The PAPI is of course a visual aid - you don’t track the PAPI using your instruments (you can indirectly but if you want to know if you are on the glide scope you look at it, not your panel).
 
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