ILS or LOC RWY ??

Aviator524

Aviator524

Well-Known Member
Hey guys,

When I went through my instrument training my instructor always told me to brief the Localizer approach in addition to the ILS when performing an ILS approach. I was told begin my timer when reaching the LOC FAF, so that I could revert to the LOC approach in the event that the GS fails during the ILS approach. Now that I am teaching students of my own I began thinking that this might not be a great idea to teach. My reasoning is because you were cleared for an ILS approach, not a LOC approach by ATC. I think that I personally would perform the missed approach, let ATC know about the failure, and get set up for a new approach. But I may be wrong. What do some of you guys think?
 
brief the approach you are expecting to do. IMO its too much info to worry about if you brief an ILS an a LOC at the same time. besides youre right about going missed and starting the whole thing over again if you happen to loose the glide slope halfway through the approach. Its still nice to see the stepdown altitudes on the LOC approach to reference during an ILS.
 
I agree with SIUav8er. I believe that there's too much of a chance to do something wrong if you're diligently flying the ILS when something goes wrong and to just decide to switch to the Loc approach (e.g., confusing DA with MDA since it was the minimums in your head to start). It's nice to know it's there, but I'll go missed and come back and do it again from the top.

Now if I was flying an engine-out approach (on a multi - or a single for that matter) I'd probably be ready to switch to the Loc...
 
Aviator524 said:
Hey guys,

When I went through my instrument training my instructor always told me to brief the Localizer approach in addition to the ILS when performing an ILS approach. I was told begin my timer when reaching the LOC FAF, so that I could revert to the LOC approach in the event that the GS fails during the ILS approach. Now that I am teaching students of my own I began thinking that this might not be a great idea to teach. My reasoning is because you were cleared for an ILS approach, not a LOC approach by ATC. I think that I personally would perform the missed approach, let ATC know about the failure, and get set up for a new approach. But I may be wrong. What do some of you guys think?
Click to expand...

Just my $.02 but I typically brief just the ILS... but not for the reason that you mentioned. Mostly, just because I don't really expect the glideslope to fail right as I'm on the approach. I grant that it COULD happen, and I'm sure that it has happened to lots of pilots throughout aviation history, but I tend to think that the chances of glideslope failure while I'm on the approach are:

1. Relatively slim
2. Not particularly serious... by which I mean that if I'm following the GS and all of a sudden I get a flag, I'll look down at the book and say, "New minimums for the LOC, crew. Cat D min is XXX, HAT is XXX," and continue on. In other words, I'll brief the new numbers if they apply, when they apply.

On the opposite side of the coin, I wouldn't critique someone for briefing the LOC numbers "in case of glideslope failure," but in my mind it just raises the question of why not brief all of the other failures that could possibly affect the approach?

"In case of two engine failure on the left wing, our new airspeed would be X and our new configuration would be Y. If we lose just the number 2 electrical bus we'll be doing X, Y, and Z. If we lose both the #2 AND the #3 bus, then we'll do A, B and C. If we lose ALL the AC buses, then we'll transition to this approach using equipment off of the emergency DC bus. If a bird comes through the window and kills the co-pilot, we'll do D, E, and F, but if the co-pilot is just bleeding profusely but says he's okay, then we're on to emergency backup plan 13 ROMEO. Any questions?"

Either way, though, I wouldn't worry too much about the whole "clearance" issue. I would probably just tell tower what I was doing, along the lines of "Tower, God's_gift_to_aviation 23, looks like we've had a glideslope failure, we're continuing with the localizer approach... Are you showing any warnings or problems on your end?"
 
Oh, I would hack the clock at the fix, though. That way transitioning to the Localizer is still a viable option... plus I hack the clock at the FAF always anyway. Helps me to keep the habit pattern so that I don't forget to do it when it's really required... but that's just me.
 
Aviator524 said:
My reasoning is because you were cleared for an ILS approach, not a LOC approach by ATC. I think that I personally would perform the missed approach, let ATC know about the failure, and get set up for a new approach. But I may be wrong. What do some of you guys think?
Click to expand...

ATC doesn't care if you fly the ILS or the LOC for the same approach. It's transparent to them.

SIUav8er said:
brief the approach you are expecting to do. IMO its too much info to worry about if you brief an ILS an a LOC at the same time. besides youre right about going missed and starting the whole thing over again if you happen to loose the glide slope halfway through the approach. Its still nice to see the stepdown altitudes on the LOC approach to reference during an ILS.
Click to expand...

It depends on the person and their ability to multitask, or not. For some, knowing an MDA in addition to a DH, and following along a few stepdown altitudes is too much for someone. For others, it isnt. Do whichever makes you comfortable.

fish314 said:
2. Not particularly serious... by which I mean that if I'm following the GS and all of a sudden I get a flag, I'll look down at the book and say, "New minimums for the LOC, crew. Cat D min is XXX, HAT is XXX," and continue on. In other words, I'll brief the new numbers if they apply, when they apply.
Click to expand...

Shack. Really not that difficult to do. But again OP, do whatever makes you comfortable....so long as you're doing it for the right reasons.
 
Aviator524 said:
Now that I am teaching students of my own I began thinking that this might not be a great idea to teach. My reasoning is because you were cleared for an ILS approach, not a LOC approach by ATC. I think that I personally would perform the missed approach, let ATC know about the failure, and get set up for a new approach.
Click to expand...


FWIW, I think your reasoning is sound.
 
Brief the ILS but set your timer if necessary so that if you do lose the glideslope you continue to track the localizer until the localizer missed approach point, at which time you fly the missed approach procedure.

That's what I was always taught anyway.
 
fish314 said:
"In case of two engine failure on the left wing, our new airspeed would be X and our new configuration would be Y. If we lose just the number 2 electrical bus we'll be doing X, Y, and Z. If we lose both the #2 AND the #3 bus, then we'll do A, B and C. If we lose ALL the AC buses, then we'll transition to this approach using equipment off of the emergency DC bus. If a bird comes through the window and kills the co-pilot, we'll do D, E, and F, but if the co-pilot is just bleeding profusely but says he's okay, then we're on to emergency backup plan 13 ROMEO. Any questions?"

Either way, though, I wouldn't worry too much about the whole "clearance" issue. I would probably just tell tower what I was doing, along the lines of "Tower, God's_gift_to_aviation 23, looks like we've had a glideslope failure, we're continuing with the localizer approach... Are you showing any warnings or problems on your end?"
Click to expand...

I KNEW I'd been missing something from my approach briefings!!
 
Aviator524 said:
Hey guys,

When I went through my instrument training my instructor always told me to brief the Localizer approach in addition to the ILS when performing an ILS approach. I was told begin my timer when reaching the LOC FAF, so that I could revert to the LOC approach in the event that the GS fails during the ILS approach. Now that I am teaching students of my own I began thinking that this might not be a great idea to teach. My reasoning is because you were cleared for an ILS approach, not a LOC approach by ATC. I think that I personally would perform the missed approach, let ATC know about the failure, and get set up for a new approach. But I may be wrong. What do some of you guys think?
Click to expand...

This is what I was taught, and currently do teach to USAF students. Not to hack the clock (we're a DME jet...), but know the Loc mins and descend no lower than them if the GS fails (unlikely) or if you descend more than 1.5 dots low (pretty likely in the training environment).
 
If you're going to do the LOC approach but they clear you for the ILS, just give them a courtesy call and tell them what's up. I didn't do that on one of my long cross countries for instrument and the tower controller nearly a brick when he got the low altitude alert on us.
 
fish314 said:
Oh, I would hack the clock at the fix, though. That way transitioning to the Localizer is still a viable option... plus I hack the clock at the FAF always anyway. Helps me to keep the habit pattern so that I don't forget to do it when it's really required... but that's just me.
Click to expand...

#1 best reason to hit the clock whether it's needed or not :)
 
I have my guys punch the clock even on RNAV approaches at the FAF just to keep it consistent. Is it needed? No...but muscle memory is what we're looking for and when you're first learning, if you get into the habit of starting the clock at the FAF for every approach, you won't forget to start it when you really need it.

Overkill, yes. But to each his own.
 
Each compnent of the ILS, LOC and GS both have redundant transmitters. Can't remember if they are fully automatic though, ie - when one fails the other comes on line immediately or if human intervention is required.

Jus as a side note for those airports so equipped, you will see cat2/3 N/A notam if any redundant system isn't available to include back-up power
 
I was taught to hack the clock in order to continue the LOC if the GS failed.

I believe it's a bad idea, personally. If I end up losing the GS during an ILS, then I'm not sure if the failure is on my aircraft, or on the ground, and what else went with it. The last thing I want to do is continue an approach without knowing the data that I'm using is reliable.

Unless there is an emergency where I'm not going around anyway, I'd prefer to take the plane around, take stock of what's going on, formulate a game plan for what we're dealing with now, and then attempt to execute a new approach. In general, completing most approaches is not so critical that the world will end if you go missed, so I figure err on the side of safety and take it around.

Or said another way, if I were to do this at my company, and something went wrong, the first thing the boss is going to ask is why I didn't just go around.
 
jtrain609 said:
I believe it's a bad idea, personally. If I end up losing the GS during an ILS, then I'm not sure if the failure is on my aircraft, or on the ground, and what else went with it. The last thing I want to do is continue an approach without knowing the data that I'm using is reliable.

Unless there is an emergency where I'm not going around anyway, I'd prefer to take the plane around, take stock of what's going on, formulate a game plan for what we're dealing with now, and then attempt to execute a new approach. In general, completing most approaches is not so critical that the world will end if you go missed, so I figure err on the side of safety and take it around.
Click to expand...



:yup: Couldn't agree more.
 
jtrain609 said:
If I end up losing the GS during an ILS, then I'm not sure if the failure is on my aircraft, or on the ground, and what else went with it. The last thing I want to do is continue an approach without knowing the data that I'm using is reliable.
Click to expand...

I agree with this. I'm going around for any loss/corruption of data. In the event of a mountain-valley turning missed in a non-radar environment, I am referring to GPS for the MAP (either denoted or based on a 3-degree slope/CAT I mins, I should be just inside of a mile from the runway). That's a bad day.

I too start my time at the FAF for muscle memory.

That being said, I too start my time at the FAF for muscle memory.
 
At the airline where I flew if you briefed the ILS, you flew the ILS. If the GS went out, you came back around and briefed the LOC. As some have pointed out there are many variables to the GS going out. Where are you on the approach? Have you descended below MDA? Have you descended below a step down?
On the flip side I was taught to set up for both- punch the clock, etc. I don't know that I would say one way is wrong and the other is correct... except that the way I do it on a given day is the correct way and the way everyone should do it.
 
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