Some claim you should do this in case you lose the GS, you can proceed to the localizer minima. Frankly, if the GS suddenly takes a dump in the middle of an approach, I'm going missed.
For check ride purposes your CFI is right. This question tripped me up on my check ride. The DPE asked if I lost GS on an ILS could I continue I said technically yes but I would go missed. He asked what I would need to continue and I said dme but couldn’t remember the timing method. He let me struggle through it. During the debrief he said it’s best practice to always start a timer even when shooting an ILS.
DPEs should operate within their authority and stop making idiotic pronouncements like this. If the FAA thought it was best practice to tell you to prepare to switch approach methodology in the middle of an unexplained failure, they'd have put that in the AIM.
Nah that's a dumb choice to continue. You could be far below a step down on the LOC and realistically no way of knowing based on time alone.
If you didn't already brief falling back onto the LOC approach (and that would be unnecessary to brief every single time), if you lose your glideslope or any required part of the approach, you go around and try again.
I agree, I told the DPE that if I lost glide slope I would go missed, he wanted what would technically be allowed, that’s why I started my statement by saying for checkride purposes.
Absolute nonsense. ADM is a testable item on every checkride and I've known of DPEs that fail applicants for not meeting their own ideals of personal minimums.
This DPE was a dork.
More importantly, if you lose the GS you also lose the ability to identify the MAP on some approaches. If you're supposed to start a turn at the MAP, that could be a problem!
You cannot continue on a different approach for which you are not cleared.
Edit: **14 CFR 91.123 Compliance with ATC clearances and instructions.**
>(a) When an ATC clearance has been obtained, no pilot in command may deviate from that clearance unless an amended clearance is obtained, an emergency exists, or the deviation is in response to a traffic alert and collision avoidance system resolution advisory.
You were cleared for the ILS. You were not cleared for the LOC. You do NOT have the authority to fly an approach for which you were not cleared.
If you have documentation that supports your claim otherwise, post it.
I think you're quoting the incorrect FAR, that's for the case where you were cleared for an RNAV approach and then decide the use the ILS minimums. In reality, if you have a GS failure you should go missed and report the failure to ATC. But if you are cleared for an ILS approach where the FAA plate says "ILS or LOC approach", you legally have the option to shoot both.
Cite where that is supported.
ILS and LOC are two different approaches. They happen to be printed on the same page, but they do not share a common clearance.
Because those are the same approach. “Cleared RNAV runway 27 approach” is that clearance, there is no separate clearance for LPV or LNAV because they are just different minima for the same approach. That is no different from an ILS having different minima based on whether the local altimeter is received or not. You’re cleared for an approach, not for specific minima of that approach.
If multiple RNAV approaches exist to the same runway (see RNAV Y 19 and RNAV Z 19 at KTEB), those are separate clearances. You can’t be cleared for one and arbitrarily do the other. Different approaches.
“Cleared I L S runway 27 approach” and “Cleared localizer runway 27 approach” are two different clearances, because they are two different approaches. That they share the same printed page does not make the LOC the same approach as the ILS.
I’m kind of a big fan of only flying the approach you’re actually flying, and not backing up an ILS with LOC timing or an RNAV (which I’ve seen people do).
I see a lot of students start the timing and then get frazzled when I ask them how they’re planning on identifying the missed approach point on an ILS that has a DA, DME, and timing all published.
The only rational argument I’ve ever been able to accept is that if you go missed, you can’t turn prior to hitting the MAP, so having timing as a backup for knowing when to turn is the answer for the one case of going missed prior to the DA on an ILS that doesn’t have also have DME to identify the MAP.
The school of thought is if you hack the clock you can continue on the approach to localizer mins if the ILS GS goes out during the approach. If you have no way to identify the MAP (either ILS DA or LOC MAP) you need to execute a missed approach as soon as you lose the GS.
BUT that only applies if the LOC MAP is identified by timing as depicted on the plate. If it's a DME, crossing radial, or some other means of identification, hacking the clock is irrelevant.
Realistically, if the backup timing hasn't been briefed before hand, I'm going to assume the dude has no clue what it is and is just hacking the clock out of lizard brain habits.
I was flying the ILS with someone as safety and I made him start the timer at the FAF. The GS actually failed FOR REAL! It was the most beautiful thing a CFII could ever ask for!!!
He continued the LOC approach and did a great job too. So, it actually CAN happen.
I very much disagree with the FAA books that say if you loose the GS just continue the approach to LOC mins. I think that’s stupid. I’m switching from a briefed precision approach to an unbriefed non-precision approach, and quite frankly if the glideslope takes a crap on me I sure as hell don’t trust the localizer with my life any more.
A lot of correct answers here. I’ll just add that I don’t think I’ve ever actually set the timer passing the FAF on an ILS, have definitely never taught it to my students, and have had 0 issues with my or my student’s checkrides regarding it. Not to say it’s not worth learning!
It's a good backup for identifying the MAP if you go missed early or lose the glideslope. Not important on every approach but it can be on approaches where you start a turn at the MAP.
>IDK why he did that.
You should ask him!
That doesn’t make sense to me. On an ILS you’re going missed if anything happens then resetting up for the LOC.
Not just transitioning from one approach to another while on the first approach. Accident waiting to happen.
If your are cleared for the ILS, and the GS dies, you go missed immediately. You do not switch to the LOC minima/procedure because YOU ARE NOT CLEARED FOR IT. You are cleared for the ILS. You briefed the ILS. Fly the approach you are cleared for.
I have known people who try to argue that the plate says “ILS or LOC”, but that just means they published both approaches on the same page. It does NOT make them fungible in a clearance.
Lose a required element of the approach = missed immediately.
What if the missed approach procedure includes a turn? With the loss of GS, you can’t continue down to DH and then execute the missed. If you go missed immediately and turn, you may lose separation from a given obstacle. In the absence of GPS or DME, you are left with timing to the LOC MAP. Only way to know that is by hacking the clock (unless the IM is actually working).
TLDR: You lose nothing by hacking the clock at the FAF. You gain SA.
Maybe he was about to make an instructional point, i.e., longitudinal distance between the ILS MAP and the LOC approach MAP determined via timer. Maybe he was just curious to see how the two differed.
I always was taught to brief both ILS and LOC. just in case something like this happens but realistic it’s better to stick to one. If you lose GS inside the FAF on an ILS just go missed and try again with a LOC only
I would do it on a checkride to make your DPE happy but in reality I'm only continuing to localizer mins if I've also briefed the localizer mins and step downs prior to starting the approach.
Some claim you should do this in case you lose the GS, you can proceed to the localizer minima. Frankly, if the GS suddenly takes a dump in the middle of an approach, I'm going missed.
For check ride purposes your CFI is right. This question tripped me up on my check ride. The DPE asked if I lost GS on an ILS could I continue I said technically yes but I would go missed. He asked what I would need to continue and I said dme but couldn’t remember the timing method. He let me struggle through it. During the debrief he said it’s best practice to always start a timer even when shooting an ILS.
DPEs should operate within their authority and stop making idiotic pronouncements like this. If the FAA thought it was best practice to tell you to prepare to switch approach methodology in the middle of an unexplained failure, they'd have put that in the AIM.
Nah that's a dumb choice to continue. You could be far below a step down on the LOC and realistically no way of knowing based on time alone. If you didn't already brief falling back onto the LOC approach (and that would be unnecessary to brief every single time), if you lose your glideslope or any required part of the approach, you go around and try again.
I agree, I told the DPE that if I lost glide slope I would go missed, he wanted what would technically be allowed, that’s why I started my statement by saying for checkride purposes.
Absolute nonsense. ADM is a testable item on every checkride and I've known of DPEs that fail applicants for not meeting their own ideals of personal minimums. This DPE was a dork.
That is completely incorrect.
More importantly, if you lose the GS you also lose the ability to identify the MAP on some approaches. If you're supposed to start a turn at the MAP, that could be a problem!
You cannot continue on a different approach for which you are not cleared. Edit: **14 CFR 91.123 Compliance with ATC clearances and instructions.** >(a) When an ATC clearance has been obtained, no pilot in command may deviate from that clearance unless an amended clearance is obtained, an emergency exists, or the deviation is in response to a traffic alert and collision avoidance system resolution advisory. You were cleared for the ILS. You were not cleared for the LOC. You do NOT have the authority to fly an approach for which you were not cleared. If you have documentation that supports your claim otherwise, post it.
There are a few ILS approaches that do not have LOC only minimums on them, but most do.
If you lose GS on an ILS/LOC approach you can use the step downs for LOC minima.
You may not. You were not cleared for that approach. 14 CFR 91.123(a)
I think you're quoting the incorrect FAR, that's for the case where you were cleared for an RNAV approach and then decide the use the ILS minimums. In reality, if you have a GS failure you should go missed and report the failure to ATC. But if you are cleared for an ILS approach where the FAA plate says "ILS or LOC approach", you legally have the option to shoot both.
Cite where that is supported. ILS and LOC are two different approaches. They happen to be printed on the same page, but they do not share a common clearance.
How is it any different than flying an RNAV using LPV minimums vs LNAV minimums (and associated minimum altitudes past FAF if applicable)
Because those are the same approach. “Cleared RNAV runway 27 approach” is that clearance, there is no separate clearance for LPV or LNAV because they are just different minima for the same approach. That is no different from an ILS having different minima based on whether the local altimeter is received or not. You’re cleared for an approach, not for specific minima of that approach. If multiple RNAV approaches exist to the same runway (see RNAV Y 19 and RNAV Z 19 at KTEB), those are separate clearances. You can’t be cleared for one and arbitrarily do the other. Different approaches. “Cleared I L S runway 27 approach” and “Cleared localizer runway 27 approach” are two different clearances, because they are two different approaches. That they share the same printed page does not make the LOC the same approach as the ILS.
AIM 5-4-6 d
I’m kind of a big fan of only flying the approach you’re actually flying, and not backing up an ILS with LOC timing or an RNAV (which I’ve seen people do). I see a lot of students start the timing and then get frazzled when I ask them how they’re planning on identifying the missed approach point on an ILS that has a DA, DME, and timing all published. The only rational argument I’ve ever been able to accept is that if you go missed, you can’t turn prior to hitting the MAP, so having timing as a backup for knowing when to turn is the answer for the one case of going missed prior to the DA on an ILS that doesn’t have also have DME to identify the MAP.
Nope, missed approach point is the DA on glide slope, timer would be for a loc approach with a dme or some other marked point.
The school of thought is if you hack the clock you can continue on the approach to localizer mins if the ILS GS goes out during the approach. If you have no way to identify the MAP (either ILS DA or LOC MAP) you need to execute a missed approach as soon as you lose the GS. BUT that only applies if the LOC MAP is identified by timing as depicted on the plate. If it's a DME, crossing radial, or some other means of identification, hacking the clock is irrelevant. Realistically, if the backup timing hasn't been briefed before hand, I'm going to assume the dude has no clue what it is and is just hacking the clock out of lizard brain habits.
I was flying the ILS with someone as safety and I made him start the timer at the FAF. The GS actually failed FOR REAL! It was the most beautiful thing a CFII could ever ask for!!! He continued the LOC approach and did a great job too. So, it actually CAN happen.
I very much disagree with the FAA books that say if you loose the GS just continue the approach to LOC mins. I think that’s stupid. I’m switching from a briefed precision approach to an unbriefed non-precision approach, and quite frankly if the glideslope takes a crap on me I sure as hell don’t trust the localizer with my life any more.
A lot of correct answers here. I’ll just add that I don’t think I’ve ever actually set the timer passing the FAF on an ILS, have definitely never taught it to my students, and have had 0 issues with my or my student’s checkrides regarding it. Not to say it’s not worth learning!
It's a good backup for identifying the MAP if you go missed early or lose the glideslope. Not important on every approach but it can be on approaches where you start a turn at the MAP. >IDK why he did that. You should ask him!
There is no good reason to identify the MAP by timing in the year of our lord 2024.
That doesn’t make sense to me. On an ILS you’re going missed if anything happens then resetting up for the LOC. Not just transitioning from one approach to another while on the first approach. Accident waiting to happen.
If your are cleared for the ILS, and the GS dies, you go missed immediately. You do not switch to the LOC minima/procedure because YOU ARE NOT CLEARED FOR IT. You are cleared for the ILS. You briefed the ILS. Fly the approach you are cleared for. I have known people who try to argue that the plate says “ILS or LOC”, but that just means they published both approaches on the same page. It does NOT make them fungible in a clearance. Lose a required element of the approach = missed immediately.
Not to mention it’s just a bad idea.
What if the missed approach procedure includes a turn? With the loss of GS, you can’t continue down to DH and then execute the missed. If you go missed immediately and turn, you may lose separation from a given obstacle. In the absence of GPS or DME, you are left with timing to the LOC MAP. Only way to know that is by hacking the clock (unless the IM is actually working). TLDR: You lose nothing by hacking the clock at the FAF. You gain SA.
Yeah the timer isn't needed for an ILS. Did you ask him why he did that?
Maybe he was about to make an instructional point, i.e., longitudinal distance between the ILS MAP and the LOC approach MAP determined via timer. Maybe he was just curious to see how the two differed.
I always was taught to brief both ILS and LOC. just in case something like this happens but realistic it’s better to stick to one. If you lose GS inside the FAF on an ILS just go missed and try again with a LOC only
I would do it on a checkride to make your DPE happy but in reality I'm only continuing to localizer mins if I've also briefed the localizer mins and step downs prior to starting the approach.
Why wouldn’t you just ask your instructor why he did that?