Glideslope Intercept Altitude

HF17

HF17

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HF17
I understand that there are two methods to intercept the glideslope. Technique 1: descend to step down fixes and intercept the glideslope at glideslope intercept altitude. Technique 2: intercept the glideslope at your last assigned altitude and verify your altitude at the outer marker. I normally use technique 1, but if I’m being vectored, or I’m in a faster airplane, or if I’m task saturated, I’ll choose technique 2.

I recently got my CFII and want to teach one technique or the other to make things as simple as possible for the student. I’m most likely going to teach technique 1, but I’m just wondering how other CFII’s teach it.

The reason why I’d avoid teaching technique 2 is because there is more to think about. You have to make sure you’re within 10nm, that you’re not on a false glideslope, and that you aren’t descending below any step down fixes.


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I have a hard time remembering when I was actually at an Outer Marker on an instrument approach. Also not sure where "intercept altitude"is?
 
The advantage to method one is that you are preparing your students for the types of approaches flown by the big planes where step downs begin well above 3000 feet. I also like shortening the amount of time I need to chase the glide slope needle. The FAA seems to like method two because less altitude adjustments means a more stabilized approach.
 
RingLaserGyroSandwich said:
The advantage to method one is that you are preparing your students for the types of approaches flown by the big planes where step downs begin well above 3000 feet. I also like shortening the amount of time I need to chase the glide slope needle. The FAA seems to like method two because less altitude adjustments means a more stabilized approach.
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My instructor is an instructor and check pilot for Southwest. He teaches both, but recommends using method 2 in real life. Less task saturation and more time to get stabilized. That's the way SWA requires they be flown.
 
Hang 4 said:
I have a hard time remembering when I was actually at an Outer Marker on an instrument approach. Also not sure where "intercept altitude"is?
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Intercept altitude is shown by the lightning bolt


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The electronic glideslope is a fixed point in space and doesn't move.

The step down altitudes are barometric and will move up and down as pressure and temperature change from standard. That can result in the glideslope being below the published step down altitude in hot/high conditions.
 
I teach what the AIM recommends in Note 2 of 5-4-5 which is Technique 1.

Why? You can defend that technique to a DPE during a checkride. Explaining why you would do otherwise could lead down a path the applicant didn't want to go down (i.e. unintended consequences).
 
Usually doing the full approach takes too much time and holding patterns and missed approaches are often rushed or skipped that I would say those are weak spots on my skill set. Being vectored in and intercepting the course is more normal and the idea would to be at the correct altitude by outer marker, given permission to intercept the course is your indicator to start your descent to the outer market altitude, from what I remember.
 
Walboy said:
I teach what the AIM recommends in Note 2 of 5-4-5 which is Technique 1.

Why? You can defend that technique to a DPE during a checkride. Explaining why you would do otherwise could lead down a path the applicant didn't want to go down (i.e. unintended consequences).
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Most stepdown altitudes on an ILS are “at or above” altitudes, not “mandatory” altitudes. A clearance of “maintain 5000 until established…” allows you to comply with “at or above” altitudes.

Some automation systems will maintain a higher altitude than the FAF altitude to intercept a glide slope or glide path, so being very clear about what you’re allowed to do here is more important than dumbing it down to not make a mistake on a checkride.
 
HF17 said:
I understand that there are two methods to intercept the glideslope. Technique 1: descend to step down fixes and intercept the glideslope at glideslope intercept altitude. Technique 2: intercept the glideslope at your last assigned altitude and verify your altitude at the outer marker. I normally use technique 1, but if I’m being vectored, or I’m in a faster airplane, or if I’m task saturated, I’ll choose technique 2.

I recently got my CFII and want to teach one technique or the other to make things as simple as possible for the student. I’m most likely going to teach technique 1, but I’m just wondering how other CFII’s teach it.

The reason why I’d avoid teaching technique 2 is because there is more to think about. You have to make sure you’re within 10nm, that you’re not on a false glideslope, and that you aren’t descending below any step down fixes.


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Click to expand...
Teach both.
 
MauleSkinner said:
Most stepdown altitudes on an ILS are “at or above” altitudes, not “mandatory” altitudes. A clearance of “maintain 5000 until established…” allows you to comply with “at or above” altitudes.

Some automation systems will maintain a higher altitude than the FAF altitude to intercept a glide slope or glide path, so being very clear about what you’re allowed to do here is more important than dumbing it down to not make a mistake on a checkride.
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I'm not disputing that. I answered the OP's question.

He's hired to get a student through a checkride and that's how the AIM recommends intercepting. If that's dumbing it down, so be it.

Plus, I don't have your experience with automated systems.
 
Walboy said:
I'm not disputing that. I answered the OP's question.

He's hired to get a student through a checkride and that's how the AIM recommends intercepting.
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He’s hired teach the student to fly instruments.
 
Just a pilot; not an instructor... however, what makes the most sense to me is a sequence:
 
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wayneda40 said:
Just a pilot; not an instructor... however, what makes the most sense to me is a sequence:
  • start with #1 -- the classic dive-and-drive
  • then add #2 -- the "stabilized approach"
  • ... and if the IR student happens to ask, "What's this VNAV stuff about?" -- and you're flying with modern avionics... then #3 VNAV for legs outside the leg leading to the FAF
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If the IR student happens to ask “what’s this VNAV stuff about” and you’re flying modern avionics, the CFII probably hasn’t done his job.

edit…and VNAV will probably continue to or past the FAF.
 
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The FAF on an ILS is GS intercept, but the ACS only allows +/-100 ft of the published altitudes on the ILS approach prior to beginning of the final segment.


Pilots are cautioned to adhere to altitudes as prescribed because, in certain instances, they may be used as the basis for vertical separation of aircraft by ATC.
 
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MauleSkinner said:
If the IR student happens to ask “what’s this VNAV stuff about” and you’re flying modern avionics, the CFII probably hasn’t done his job.
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Thread drift.

I think an important point related to modern avionics is being able to teach the student how to recognize various failure modes, what the consequences are, how to mitigate them, and how that failure might affect other pieces of equipment. I for one don't have the breadth of experience with all the combinations of autopilots, navigators, PFDs, FDCs, AHRS etc. to be able to explain the nuances of each piece of equipment. So I stick to what I know, which admittedly isn't a whole lot.

In some cases, I can pick up an manual and mostly figure things out, but that isn't instructional level of knowledge IMO.

So for a CFII to do his job IMO, he must recognize:

there are known unkowns and there are also unknown unknowns with regard to teaching instruments with modern avionics. Be careful what you get yourself into.
 
I teach it depends on the conditions. Why would I step down into the muck to intercept the glideslope when I might be able to intercept with a clear blue sky. Or if I am in the muck and might get out of it by stepping down then I will probably step down. If it isn't going to matter than I tend to prefer to intercept high and have longer to stabilize the descent, i.e "interception done, one more task out of the way early." If the autopilot is flying the approach I also am able to confirm it has acquired the glide slope earlier.

Brian
CFIIG/ASEL
 
Walboy said:
I teach what the AIM recommends in Note 2 of 5-4-5 which is Technique 1.

Why? You can defend that technique to a DPE during a checkride. Explaining why you would do otherwise could lead down a path the applicant didn't want to go down (i.e. unintended consequences).
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Isolating the first sentence of 5-4-5 b. 4. Note 2 and ignoring everything else said elsewhere in the AIM and other publications about the advantages of, and recommendations for doing stabilized, constant angle of descent Approaches does not seem wise to me.
 
wayneda40 said:
Just a pilot; not an instructor... however, what makes the most sense to me is a sequence:
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That sounds like a pretty good idea to me.
 
Walboy said:
Thread drift.

I think an important point related to modern avionics is being able to teach the student how to recognize various failure modes, what the consequences are, how to mitigate them, and how that failure might affect other pieces of equipment. I for one don't have the breadth of experience with all the combinations of autopilots, navigators, PFDs, FDCs, AHRS etc. to be able to explain the nuances of each piece of equipment. So I stick to what I know, which admittedly isn't a whole lot.

In some cases, I can pick up an manual and mostly figure things out, but that isn't instructional level of knowledge IMO.

So for a CFII to do his job IMO, he must recognize:

there are known unkowns and there are also unknown unknowns with regard to teaching instruments with modern avionics. Be careful what you get yourself into.
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But per your post I originally responded to, the reason you posted for not teaching “at or above” altitudes is because you don’t want to teach them something that they might not be able to explain to a DPE. In and of themselves, “at or above,” “at or below”, and “mandatory” altitudes are important considerations for instrument flying. Not being able to explain and/or apply them could just as easily result in a bust.
 
MauleSkinner said:
In and of themselves, “at or above,” “at or below”, and “mandatory” altitudes are important considerations for instrument flying. Not being able to explain and/or apply them could just as easily result in a bust.
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I'm not disagreeing with anything you say. I don't think intercepting a glideslope covers the universe of situations where altitudes are important so I'm not sure why you're pursuing this angle. The note in the AIM I referred to makes the same points you're making.
 
WDD said:
Fly at assigned altitudes, when established hit the FAF at the published altitude, and start decent. I like simple.
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When established on a Glideslope you do not have to comply with an FAF altitude. Doing so on hot days might have you having to descend back down and intercept the Glideslope from above. It’s the Fix Altitudes outside of the FAF that you must comply with.
 
Larry in TN said:
"At CRCUS, Cleared ILS 25L, Maintain 210 Knots"


...at or below the published GS intercept altitude.
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Ideally where you intercept at or above the published altitude for the intermediate segment.
 
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Walboy said:
I'm not disagreeing with anything you say. I don't think intercepting a glideslope covers the universe of situations where altitudes are important so I'm not sure why you're pursuing this angle. The note in the AIM I referred to makes the same points you're making.
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I think it is important to know the definition of Glideslope Intercept Altitude. Note the third word.

GLIDESLOPE INTERCEPT ALTITUDE− The
published minimum altitude to intercept the
glideslope in the intermediate segment of an
instrument approach. Government charts use the
lightning bolt symbol to identify this intercept point.
This intersection is called the Precise Final Approach
fix (PFAF). ATC directs a higher altitude, the
resultant intercept becomes the PFAF.
(See FINAL APPROACH FIX.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
 
Walboy said:
I'm not disagreeing with anything you say. I don't think intercepting a glideslope covers the universe of situations where altitudes are important so I'm not sure why you're pursuing this angle. The note in the AIM I referred to makes the same points you're making.
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So why would you not teach technique 2?
 
MauleSkinner said:
So why would you not teach technique 2?
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Because the AIM says, "The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude."

Seems crystal clear to me. So why not teach what the FAA says the intent should be?

I'm not sure how anyone can find fault with that. I'd say it's a good practice to follow the AIM.
 
Walboy said:
Because the AIM says, "The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude."

Seems crystal clear to me. So why not teach what the FAA says the intent should be?

I'm not sure how anyone can find fault with that. I'd say it's a good practice to follow the AIM.
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But now that you’ve learned that some automation can operate counter to the AIM recommendation, do you think pilots should be trained bypass that automation even though it’s a legitimate method?

What pilots learn in their initial instrument training is often where they stop learning. I see a lot of pilots dumb down the automation because they don’t understand that it’s allowed to do what it does, and others who blindly follow the automation into a violation because they really don’t understand their charts.
 
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MauleSkinner said:
But now that you’ve learned that some automation can operate counter to the AIM recommendation, do you think pilots should be trained bypass that automation even though it’s a legitimate method?
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I know you're highly accomplished pilot and I'm pretty sure you're an examiner, so I respect your credibility and always pay attention to what you have to say.

But...I'm not teaching highly automated systems, so I have no opinion and it would be conjecture at best. If an instrument student can intercept at a specific altitude consistently, he can progress to intercepting at higher altitudes with ease when the automation you refer to comes into play.

You're not presenting a convincing case. You're making a strawman argument by introducing "some automation". I've already acknowledged that's beyond what I know. I'm simply stating there's nothing wrong with following the FAA's guidance.
 
Walboy said:
Because the AIM says, "The ILS glide slope is intended to be intercepted at the published glide slope intercept altitude."

Seems crystal clear to me. So why not teach what the FAA says the intent should be?

I'm not sure how anyone can find fault with that. I'd say it's a good practice to follow the AIM.
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Are you literally stopping reading after that one sentence and ignoring everything else written that is relevant to it?
 
luvflyin said:
Are you literally stopping reading after that one sentence and ignoring everything else written that is relevant to it?
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No, I'm not. Why?

I think the OP has seen both sides of the argument by now. Do what you think is best.
 
Just a flib flyer. I use #1 (descend to minimum segment altitude priormto GS intercept) if I think there is a chance I will break out into VFR at that altitude. I use #2 (intercept the glideslope at altitude coming out of the IAF) if breaking out early is unlikely. That gives me plenty of time to establish initial reference heading and descent rate for the approach. We did both methods during training. DPE didn't have any problem with whatever I used on the check ride for the ILS (probably #2). I do the same for LPV approaches. Probably doesn't matter as long as you are above minimum altitudes for the segment you are on.
 
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