yep it has ...FAF altitude must check
Close call. You can't always trust the ILS.
- Thread starter stratobee
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yep it has ...FAF altitude must check
If you watched the needle come down to meet you at the intercept, that should really be sufficient, if you get the next point as well, the chances of you having a problem are extremely small.
Sluggo63
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I'm curious how you do this with a NOAA plate. I know Jepps have the recommended altitudes on them, but how about something like this ILS into TEB?
Looks like that just gives the outer marker,so that's all I'd check there. This is also one of the reasons I plug the ILS into the # 2 head when I do approaches.
SbestCFII
Line Up and Wait
The main issue here wasn't just the faulty GS transmission, but the pilots failure to immediately realize it. When the indicator showed the GS indicator at the wrong location AND altitude, it should have been immediately obvious.
Recall that when you perform an ILS, either full procedure or vectored, you'll first be established on the localizer, then intercept the glideslope at least 2-3 miles at a specified location and at the specified altitude. The glideslope indicator will always be above you, and will "come down to meet you" as you proceed along the localizer and center at the specified altitude and location on the approach chart.
When the 767 was showing a perfectly centered GS capture at the wrong DME location and altitude, they should have picked up on it. When the plane suddenly picked up speed and started an unusually high descent rate, they got distracted managing that issue. If you've flown long enough, you might remember the FAA have concerns over the effects of cockpit automation on pilots. You can see that here.
Recall that when you perform an ILS, either full procedure or vectored, you'll first be established on the localizer, then intercept the glideslope at least 2-3 miles at a specified location and at the specified altitude. The glideslope indicator will always be above you, and will "come down to meet you" as you proceed along the localizer and center at the specified altitude and location on the approach chart.
When the 767 was showing a perfectly centered GS capture at the wrong DME location and altitude, they should have picked up on it. When the plane suddenly picked up speed and started an unusually high descent rate, they got distracted managing that issue. If you've flown long enough, you might remember the FAA have concerns over the effects of cockpit automation on pilots. You can see that here.
SbestCFII
Line Up and Wait
The ILS at TEB is pretty simple. You'll either be vectored to the localizer or use the feeder route from the Solberg VOR/DME. Inside VINGS, descend to 1500 (mandatory) at DANDY (keeps you out of the Class B above). Pass DANDY and descend to 1300. Expect that the GS needle will move down and have GS intercept just before the LOM at 1300 where you will begin descent, then as you pass over the LOM, your altitude on the GS should be about 1284. It's a busy-looking chart, but is a pretty basic approach.
Clip4
Touchdown! Greaser!
Old school instrument training emphasized cross check, verification and situational awareness much more than todays GPS world.
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SbestCFII
Line Up and Wait
The intercept altitude is the acid test. Wrong place, wrong time - no go. Intercept the GS at the right place and at the right altitude - go. There is no way to track the altitude(s) going down the GS, unless you want to mathematically calculate them on the way down.
From the GS intercept of 1500' at my home airport (KJNX) to the DA of 347' is 3.5 NM, so the rate of descent is 329 Ft/NM. So I could use DME or GPS to check the approximate altitude:
2.5 miles from DA = 1171 FT
1.5 miles from DA = 842 FT
0.5 miles from DA = 513 FT
0.0 miles from DA = 348 FT
Unless you do all this in advance and have someone else to call it off to you, it's a lot of work and cross-checking during SPIFR, so just make sure you correctly intercept the glideslope and follow it. When you get to DA, if you don't see the ALS, VGSI, or runway elements, you go missed.
From the GS intercept of 1500' at my home airport (KJNX) to the DA of 347' is 3.5 NM, so the rate of descent is 329 Ft/NM. So I could use DME or GPS to check the approximate altitude:
2.5 miles from DA = 1171 FT
1.5 miles from DA = 842 FT
0.5 miles from DA = 513 FT
0.0 miles from DA = 348 FT
Unless you do all this in advance and have someone else to call it off to you, it's a lot of work and cross-checking during SPIFR, so just make sure you correctly intercept the glideslope and follow it. When you get to DA, if you don't see the ALS, VGSI, or runway elements, you go missed.
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That's because in today's GPS world the box makes the cross checking much simpler, it just doesn't take the time and effort that it did to maintain a much greater level of situational awareness.
Fearless Tower
Touchdown! Greaser!
There may not be a way to track specific altitudes, but you can check the descent rate. If you are flying a typical piston single and having to maintain a 1000+FPM descent to maintain GS, then something might not be quite right.
Yep, lots of failure modes, lots of clues.
lots of times you intercept further out than the FAF...hence the long established calls "GS ALVE" "GS Captured "...the biggest reason you check the FAF altitude is to confirm your altimeters are set properly.
Unless you have RA altitudes on the plate, just what are you checking?
petrolero
Pattern Altitude
What are those two points? That's what I'm trying to understand.
I'm looking at the AeroNav chart for the KAPA ILS 35R and I see only one point that combines a distance or fix with a specified altitude - that is 7977' at CASSE. That is only 23 feet below the intercept altitude of 8000' and in practice the intercept and crossing of CASSE are nearly simultaneous.
Now if I intercepted at 9000 and descended down 1000' and I cross-checked 7977 at CASSE then I'd be plenty confident in the GS angle. But intercepting at 8000 doesn't give me that. Sounds like the Jepp charts have an advantage in providing that list of distances and altitudes.
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Velocity173
Besides checking my MSL altimeter with the GS interception altitude, I give myself a halfway point to make sure my descent rate coincides with the ILS. For a 3 degree glidpath, that's 318 FPNM. Take my altitude at GS interception and subtract 318 for each mile. The RA is a back up but ONLY in flat terrain. If it's not flat then those altitudes in final aren't going to mesh with the MSL altimeter.
I also glance at the RA at DH to see if it matches HAT. Once again, ONLY accurate in flat terrain and only as a backup. Altimeter is primary. Having the "low bug" set to HAT will give a good wake up as well if you get an erroneous glidepath that's trying to descend you significantly below the norm.
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RotorAndWing
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Here is a couple of charts I use. Look to the left of the side view and you see the ILS/DME with the corresponding altitudes. On the right side you will see the "FAP-MAP" with ground speed and rate of descent table.
Busflyer
Line Up and Wait
Don't know who R&W flies for but my airline requires just the GS crossing altitude. I think that's pretty standard.
RotorAndWing
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For US carriers, yes.
NoHeat
Final Approach
R&W, I am just curious about the missed approach at Manila. It assumes that you will reach the 145 radial before you have climbed to 4000', but what would you do if it turned out the other way, you got up to 4000' before the 145 radial. Would you then just slip the radial altogether and proceed directly to the hold over the airfield?
RotorAndWing
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NoHeat
Final Approach
Thanks. And how do you use the table of altitudes vs DME that you mentioned? Is it your standard procedure to check altitude at one mile intervals using this table, while descending the glide slope? If so, how large must the discrepancy be, to cause you to go missed?
RotorAndWing
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The PM cross checks. Not really any guidance on discrepancy, they leave that up to the crew.
aterpster
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aterpster
RotorAndWing
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Define "most". Out side the US operators use various charts, NavTech, Lido, Aerstratus, etc.
To me personally, I like Jepps, but there are many more in use.
aterpster
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aterpster
No doubt about it. But, Jepp is still the 900 pound gorilla. The Jepp chart is quite different in some respects.
petrolero
Pattern Altitude
This.
I'm not going to switch to Jepp charts for the 1 in 50 flights in which I have to fly an ILS in the soup and the 1 in 5,000 flights in which there might be an unNOTAMed problem with the GS angle.
I couldn't find a simple iOS calculator for this at quick glance, so I created an Excel spreadsheet (I have Excel on my iPad) that calculates the altitude-on-GS vs distance (in both distance-to-threshold and DME if given) based on any GS angle and any intercept altitude. It has a table that I can copy and paste onto my plate in FF if I want to take it that far (read: not likely). It also calculates my FPNM at any ground speed. But ground speed varies, angle doesn't.
So for 15 minutes of work I have a jerry-rigged Jepp chart.
nosehair
Cleared for Takeoff
Old school always taught a variety of ways to check this stuff. Lots of memories here.
One thing- I see a lot on these boards is the statement that one would not switch to a LOC after the FAF, they would go missed and start over.
Old school mindset was (is) to start with the LOC (the reason we start the clock at FAF), and use the Glideslope as long as it is performing. As long as you don't go below LOC mins until you are confident that the Glideslope is operating properly.
If you are at your alternate with not much fuel, a missed may not be an alternate.
Shoot! I've been in tstms where a missed was no way in heck an option.
I think (old school ) that thinking you can "just go missed" is very bad planning.
One thing- I see a lot on these boards is the statement that one would not switch to a LOC after the FAF, they would go missed and start over.
Old school mindset was (is) to start with the LOC (the reason we start the clock at FAF), and use the Glideslope as long as it is performing. As long as you don't go below LOC mins until you are confident that the Glideslope is operating properly.
If you are at your alternate with not much fuel, a missed may not be an alternate.
Shoot! I've been in tstms where a missed was no way in heck an option.
I think (old school ) that thinking you can "just go missed" is very bad planning.