Timing an ILS Approach or Not?

FreqFlyrJr

FreqFlyrJr

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LuckyLindy
Evening everyone! I'm a CFI-I at a popular school in the Mississippi area. Recently we got a new flight instructor in who has about the same experience as I have, but different ideas on appropriate procedures. I'll give you the scenario, and I'd like to hear what each of you thinks about the situation.

Here's the scenario:

You're on an ILS approach to an airport whose minimums are 200'. The Touchdown Zone Elevation is 0' MSL. At approximately 200', you see the lights of the threshold, so you continue to descend to 100'. Given that you do not make visual contact with the required markings/lights prescribed in 91.175(l), when do you go missed?
​
Here are the two opinions that we differ on:

1) The pilot should be keeping time of the ILS (from the FAF as prescribed on the chart). After descending to 100', the pilot should maintain 100' until the time is up, then execute his/her missed approach.

2) The pilot is not required to keep the time of the ILS. After descending to 100', the pilot should decide if he/she has the proper visibility, markings, or lights to proceed past 100'. If they do not, the pilot should immediately go missed after reaching 100' because they are already passed the DH, effectively making 100' the new DH.
​
I'll chime in with which opinion I support later on in the discussion. I look forward to seeing what you all think about this scenario, and any FAR references you can make.
 
Number 2. You're not changing the DH though. It remains the same. You don't need to time an ILS because you're going missed at the DH. Some people make the case for timing an ILS just in case they lose the GS and it "turns into" a LOC approach. If that happens to me, I'd just go missed.
 
Well, not all ILSs have timing, so #1 certainly can't be universal....

KSNS ILS RWY 31 is an example. There is a separate LOC/DME approach to the same runway that does have timing.
 
Plus, full scale deviation without initiating a missed is a bust on a checkride.
 
Number two. I briefed it as an ILS, I'm flying the ILS.

Down low with a squirrelly glideslope indication and flipping charts on the iPad is no time or place to be changing my mind, unless I think I'll run out of gas going back up and doing another approach.

And I'm sure not going to teach a student to fiddle around like that during the approach. Good way to throw yourself off your game plan and miss a gear handle or worse.
 
Time the localizer approach, on the ILS you go missed at the DH.
 
There are two reasons to time an "ILS or LOC" approach.

One is on the theory that you can switch to the LOC if you lose the glideslope on the way down. Yeah, it's possible. I even did it once, but timing was irrelevant because the ceilings were high. Would I recommend the strategy with low ceilings given the likely delay in mentally processing the loss and going "oh crap!"? No.

The second is because we are creatures of habit. So it makes sense to hit the timer on every approach, whether it requires timing or not. Of course to some there's no reason to time any approach if one has certified GPS since the MAP is in the database, but we're talking about training here.

Two is a correct statement. Assuming you have the approach lights permitting you to descend below DA, you go missed as soon as you realize you don't have the required visibility. The MAP is for the LOC approach, and you are already way below MDA.
 
Numero dos...clearly.

A couple small words of caution in your wording though.... even though you are correct.

1) 200 feet is a "decision altitude" (with TDZE 0, it's also the DH), not "minimums".

2) Once your stated reference is in sight, you can descend to 100' above TDZE. Some folks incorrectly say you can descend another 100'.
Could be a big difference.

Again, you had it correct, but if you are debating it's advisable to use precise wording so they can't come back at you.

Just my 2¢
 
#3 continue down and land since I have EVS with a HUD. I've been able to see the runway for miles already with the IR.
 
midlifeflyer said:
There are two reasons to time an "ILS or LOC" approach.

One is on the theory that you can switch to the LOC if you lose the glideslope on the way down. Yeah, it's possible. I even did it once, but timing was irrelevant because the ceilings were high. Would I recommend the strategy with low ceilings given the likely delay in mentally processing the loss and going "oh crap!"? No.

The second is because we are creatures of habit. So it makes sense to hit the timer on every approach, whether it requires timing or not. Of course to some there's no reason to time any approach if one has certified GPS since the MAP is in the database, but we're talking about training here.

Two is a correct statement. Assuming you have the approach lights permitting you to descend below DA, you go missed as soon as you realize you don't have the required visibility. The MAP is for the LOC approach, and you are already way below MDA.
Click to expand...

As is always the case on POA, someone asks a question, an answer pops up immediately in my head, and then after I scroll through the responses, midlifeflyer Mark has already read my mind and stole my answer verbatim.
 
NJP_MAN said:
The FAA just announced a new rule allowing landing with EVS. You can dispatch and even begin an approach below mins if you have EVS
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Begin an approach below mins when part 91 has always been allowed. Landing with in flight vis below mins...?? If that has changed please point me in the right direction.

Yes, I understand it's "in flight" visibility, but you won't win that fight if there is RVR reporting.
 
C
Kritchlow said:
Begin an approach below mins when part 91 has always been allowed. Landing with in flight vis below mins...?? If that has changed please point me in the right direction.

Yes, I understand it's "in flight" visibility, but you won't win that fight if there is RVR reporting.
Click to expand...
Check the link I posted in the edit. It's 91 91K 135 and 121 approved.
 
NJP_MAN said:
C

Check the link I posted in the edit. It's 91 91K 135 and 121 approved.
Click to expand...
Okay... so is that saying any airplane with that system can land with zero RVR, even if the runway, airplane, and crew are only certified to cat 1 1800 minimums??
 
Yes as l
Kritchlow said:
Okay... so is that saying any airplane with that system can land with zero RVR, even if the runway, airplane, and crew are only certified to cat 1 1800 minimums??
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yes as long as the training is met and an LOA is had. Flying EVS in my experience is superior to day VFR with unlimited viz. The airport is so much more identifiable.
 
NJP_MAN said:
Yes as l
yes as long as the training is met and an LOA is had. Flying EVS in my experience is superior to day VFR with unlimited viz. The airport is so much more identifiable.
Click to expand...
So all Cat 3 approaches, aircraft certification, training, and runway certification just became obsolete overnight?

Instead, install that system, get the required training, and every runway becomes a zero visibility runway..??
 
Th
Kritchlow said:
So all Cat 3 approaches, aircraft certification, training, and runway certification just became obsolete overnight?

Instead, install that system, get the required training, and every runway becomes a zero visibility runway..??
Click to expand...
Thats the magic of it. However the only 121 operators I see with EVS currently are cargo ops like FedEx. The MD11 with the camera looks so cool BTW.
 
NJP_MAN said:
Th

Thats the magic of it. However the only 121 operators I see with EVS currently are cargo ops like FedEx. The MD11 with the camera looks so cool BTW.
Click to expand...
I'm sure that will change if what you say is true.
Cat 3B approaches require autoland systems. I'm betting EVS will be vastly cheaper than everything currently associated with Cat IIIB approaches.
 
Kritchlow said:
I'm sure that will change if what you say is true.
Cat 3B approaches require autoland systems. I'm betting EVS will be vastly cheaper than everything currently associated with Cat IIIB approaches.
Click to expand...
I agree. What makes it so great is you can see everything. With the cat3b you're still just trusting the equipment. With EVS you can trust your eyes. I've never seen any latency with the camera and can't say it's impossible, but it's amazing stuff when you can see the runway 10 NM out when it's at minimums. Plus the symbology that depicts the runways and extended centerlines is next level. You feel like robocop or a terminator with all the info available.
 
NJP_MAN said:
I agree. What makes it so great is you can see everything. With the cat3b you're still just trusting the equipment. With EVS you can trust your eyes. I've never seen any latency with the camera and can't say it's impossible, but it's amazing stuff when you can see the runway 10 NM out when it's at minimums. Plus the symbology that depicts the runways and extended centerlines is next level. You feel like robocop or a terminator with all the info available.
Click to expand...
I always figured the Feds would approve synthetic vision before an IR system.
I always figured your windscreen would look like a simultor and we would be doing visual approaches, even following traffic, to a 0/0 landing in Aspen.

But this is interesting...
 
Kritchlow said:
I always figured the Feds would approve synthetic vision before an IR system.
I always figured your windscreen would look like a simultor and we would be doing visual approaches, even following traffic, to a 0/0 landing in Aspen.

But this is interesting...
Click to expand...
I think synviz is scary to them because there are positional errors even though they are minimal if not negligible now days. It really is a sight to behold. EVS with a FBW aircraft is unbelievable. Put the path indicator on the touchdown zone and let go. Hand flying feels like the autopilot is on. If I remember correctly you fly the bus so you know. But add EVS and it's a video game.
 
Brad Z said:
As is always the case on POA, someone asks a question, an answer pops up immediately in my head, and then after I scroll through the responses, midlifeflyer Mark has already read my mind and stole my answer verbatim.
Click to expand...
decoding-inner-voice.jpg
 
S.V., as good as it is when used properly, does not have the necessary terrain fidelity to be equivalent to the real world.
 
FreqFlyrJr said:
Evening everyone! I'm a CFI-I at a popular school in the Mississippi area. Recently we got a new flight instructor in who has about the same experience as I have, but different ideas on appropriate procedures. I'll give you the scenario, and I'd like to hear what each of you thinks about the situation.

Here's the scenario:

You're on an ILS approach to an airport whose minimums are 200'. The Touchdown Zone Elevation is 0' MSL. At approximately 200', you see the lights of the threshold, so you continue to descend to 100'. Given that you do not make visual contact with the required markings/lights prescribed in 91.175(l), when do you go missed?
​
Here are the two opinions that we differ on:

1) The pilot should be keeping time of the ILS (from the FAF as prescribed on the chart). After descending to 100', the pilot should maintain 100' until the time is up, then execute his/her missed approach.

2) The pilot is not required to keep the time of the ILS. After descending to 100', the pilot should decide if he/she has the proper visibility, markings, or lights to proceed past 100'. If they do not, the pilot should immediately go missed after reaching 100' because they are already passed the DH, effectively making 100' the new DH.
​
I'll chime in with which opinion I support later on in the discussion. I look forward to seeing what you all think about this scenario, and any FAR references you can make.
Click to expand...


#2

You drop 100', if ya still got nothing go around

As for timing, nope

If I'm shooting a ILS all the the way down to 200' off the deck and ANYTHING starts acting stupid, I'm going around and shooting a diffrent approach or going to a diffrent airport

This is not the place to try to "make it work". Plenty of shredded aluminum and flesh from people who tried to force square pegs into round holes.
 
midlifeflyer said:
There are two reasons to time an "ILS or LOC" approach.

One is on the theory that you can switch to the LOC if you lose the glideslope on the way down. Yeah, it's possible. I even did it once, but timing was irrelevant because the ceilings were high. Would I recommend the strategy with low ceilings given the likely delay in mentally processing the loss and going "oh crap!"? No.

The second is because we are creatures of habit. So it makes sense to hit the timer on every approach, whether it requires timing or not. Of course to some there's no reason to time any approach if one has certified GPS since the MAP is in the database, but we're talking about training here.

Two is a correct statement. Assuming you have the approach lights permitting you to descend below DA, you go missed as soon as you realize you don't have the required visibility. The MAP is for the LOC approach, and you are already way below MDA.
Click to expand...
Another reason to "time" the approach is so you'll know when to start the turn if the missed approach has turns and you abandon the approach early. If the MAP has a "location" defined, like a MM, intersection or DME Fix, you'd use that of course. The OP's example 1) that you would level off and maintain 100 feet, after having passed the MAP, until some time has passed, is so ridiculous that I thought the post was a joke.
 
FreqFlyrJr said:
I'll chime in with which opinion I support later on in the discussion. I look forward to seeing what you all think about this scenario, and any FAR references you can make.
Click to expand...

What isn't clear about this language from 91.175?

(c) Operation below DA/ DH or MDA. Except as provided in paragraph (l) of this section, where a DA/DH or MDA is applicable, no pilot may operate an aircraft, except a military aircraft of the United States, below the authorized MDA or continue an approach below the authorized DA/DH unless -

(1) The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers....

(2) The flight visibility is not less than the visibility prescribed in the standard instrument approach being used; and

(3) Except for a Category II or Category III approach where any necessary visual reference requirements are specified by the Administrator, at least one of the following visual references for the intended runway is distinctly visible and identifiable to the pilot:

(i) The approach light system, except that the pilot may not descend below 100 feet above the touchdown zone elevation using the approach lights as a reference unless the red terminating bars or the red side row bars are also distinctly visible and identifiable.
Click to expand...

I cite only the ALS requirement because your premise appears to be that none of the other required visual references are present. If the ALS has red terminating bars or red side row bars distinctly visible and available you can continue to descend below 100 because the presumption is that either the runway or runway edge lights will soon become visible, presuming you continuously have the required flight visibility. And, the descent cannot be stopped at 100 feet because that would violate being continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers.
 
luvflyin said:
Another reason to "time" the approach is so you'll know when to start the turn if the missed approach has turns and you abandon the approach early. If the MAP has a "location" defined, like a MM, intersection or DME Fix, you'd use that of course. The OP's example 1) that you would level off and maintain 100 feet, after having passed the MAP, until some time has passed, is so ridiculous that I thought the post was a joke.
Click to expand...

Or if you're /G you can use that, which is preferred.

If you go missed early, start on up, change nav source to GLS, start your turn when it sees you're over the missed. Bada bing
 
midlifeflyer said:
The second is because we are creatures of habit. So it makes sense to hit the timer on every approach, whether it requires timing or not. Of course to some there's no reason to time any approach if one has certified GPS since the MAP is in the database, but we're talking about training here.
Click to expand...
I think that there is a lot to be said for this. It's the only reason that I try to do so, because I really think the first reason is a fool's errand. Also, in some cases the localizer FAF isn't the same as the ILS FAF. (for example, see: http://155.178.201.160/d-tpp/1703/06452IL25.PDF ) Then what do you do? Now you have to figure out when to really start timing.
 
Timing an approach was always the thing I missed when doing approaches for my instrument rating. I'd get everything configured, briefed and then when I hit the FAF I'd fly the approach without making note of the time. I flew an ILS with someone and about halfway down I realized I'd forgotten to start the timer and immediately berated myself for it. The person I was flying with didn't seem to think it was a big deal.

Doing a bunch of approaches after I got my rating on my own, I again, forgot to set the timer. But I realized something. When you fly an ILS to minimums in rough, actual IMC conditions, you need to fly the plane and not be looking at a stopwatch on the way down. Single pilot IFR ain't easy sometimes.

I was always given the same reasoning @midlifeflyer mentioned about switching to loc if you lose the glideslope. Still don't use it though, even though I DO have it in my mind as a to do..it never gets done..
 
I never time the ILS due to the fact that if I have an equipment failure such as the GS, I'm going missed anyway. The same reason as Nate said, I briefed an ILS and that's what I'm planning on doing. I'm not going to switch to a LOC approach. I'll just go missed and come back and shoot the LOC.
 
I'm with Jordane93...if you are cleared for the ILS and cannot complete it, go around for another try. You have not been cleared for the LOC.

Bob
 
jordane93 said:
I never time the ILS due to the fact that if I have an equipment failure such as the GS, I'm going missed anyway. The same reason as Nate said, I briefed an ILS and that's what I'm planning on doing. I'm not going to switch to a LOC approach. I'll just go missed and come back and shoot the LOC.
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So, you're on an ILS and the GS fails. When do you make your first turn?

"Immediately" can put you in a mountainside for certain ILSs. The KSBD ILS is one where I'd be concerned about turning early OR late. DME or GPS is not required for that approach.
 
MAKG1 said:
So, you're on an ILS and the GS fails. When do you make your first turn?

"Immediately" can put you in a mountainside for certain ILSs. The KSBD ILS is one where I'd be concerned about turning early OR late. DME or GPS is not required for that approach.
Click to expand...
Typically I'm flying with both DME and a GPS so it's not an issue.
 
MAKG1 said:
So, you're on an ILS and the GS fails. When do you make your first turn?
Click to expand...
Any instrument-rated pilot should be able to fly a localizer accurately enough that "when I get full scale deflection" would be just as accurate as timing.
 
Like the others #2. Also I don't time unless I'm shooting a LOC. Technically your not cleared for the LOC if you should lose the G/S. Plus I don't want to have to change horses midstream.

Especially 121 I would go from an easy approach to an asinine approach.
 
MAKG1 said:
So, you're on an ILS and the GS fails. When do you make your first turn?

"Immediately" can put you in a mountainside for certain ILSs. The KSBD ILS is one where I'd be concerned about turning early OR late. DME or GPS is not required for that approach.
Click to expand...
It will be just as accurate to see what altitude you're at and assume 600' per minute descent. It really is not rocket science, and timing for groundspeed is suspect at best.
Besides... every single missed approach on the planet that I've ever seen has the same first root-word.

"Climb"
 
You've lost me. The threshold lights are one of the things in 91.175(l) that permits you to leave the DA/MDA or go below 100'. Did you mean the approach lights?

It's not clear what you're timing. You can't descend below 100' (yes it's another decision point) without one of the listed items.
 
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