Pitch-up Upsets due to ILS False Glide Slope
Technically, an ILS doesn't have a FAF, it has a glide slope intercept altitude and a Glideslope on course indication at that altitude. (TERPS)
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...and that is the point I made in post #2? Used to be known as airmanship..........
EDIT: Erm - here we go agan with time travel. This was posted in response to Pace (now post #25???), so unless he/she deleted and reposted the 'clock' is squirly.
EDIT: Erm - here we go agan with time travel. This was posted in response to Pace (now post #25???), so unless he/she deleted and reposted the 'clock' is squirly.
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this event would not have happened WITHOUT a false glideslope.
That is not the point I was trying to make
The point I was making is we should never trust anything and always cross reference with things like altitude/distance points on the charts to confirm against the glide then in that sense a false glide is irrelevant in the sense that the pilots would notice the spurious indications and react accordingly.
To be certified for use, an ILS G/S must be satisfactorily suppressed to avoid false G/S below the designated G/S. Therefore, the G/S must be captured from below because false glideslopes above the designated glideslope can, and may, exist.
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Onceapilot, capture from below should be the procedure, because it's safe.
However, in practice, ATC asks you to capture from above
once in a while... a capture from above is also part of a CDA. (And people sleeping under an approach path appreciate any reduction of jet noise.)
But the automation can do very nasty things to you (fly the plane into stall
) if you fail to capture the glidescope from above. Good to be warned about that! 
However, in practice, ATC asks you to capture from above
once in a while... a capture from above is also part of a CDA. (And people sleeping under an approach path appreciate any reduction of jet noise.)But the automation can do very nasty things to you (fly the plane into stall
) if you fail to capture the glidescope from above. Good to be warned about that!
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As BOAC pointed out it is not exactly rocket science. However this whole thread could serve as a nice ad for GLS approaches, no wrong glideslopes to capture there.
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The Dutch are a bit too fond of being 'slick' IMHO.
Most of my captures from above have been at AMS, and I remember the Turkish accident was another example.
I remember one occasion at Schipol where the instruction was 'follow the glide slope, you'll get the localiser in a minute'.
The Dutch are very keen and very good. Sometimes a bit too much so.....
Most of my captures from above have been at AMS, and I remember the Turkish accident was another example.
I remember one occasion at Schipol where the instruction was 'follow the glide slope, you'll get the localiser in a minute'.
The Dutch are very keen and very good. Sometimes a bit too much so.....
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Hopefully with the spread of VNAV/GPS approaches we will see less of this. It is, however, a useful reminder for crews on the 'perils' of false glideslopes, the need to think about autopilot useage, and the well-worn principle of 'know where you are' plus a lesson for Eindhoven ATC to take (more?) note of the winds.
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The approach FAF/FAP location is set by the Approach segment OCS meeting the Intermed segment OCS with a 500' ROC. It is possible to have a FAF, then a turn to the final approach segment.
From the video, there were far more problems indicated. ATC vectored the ac to a short final, which the ac descent rate was not able to accomplish. They turned on final and were 1000' high on GS!
From the video, there were far more problems indicated. ATC vectored the ac to a short final, which the ac descent rate was not able to accomplish. They turned on final and were 1000' high on GS!
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AtomKraft: Yes, as they descended onto the glide slope from above.
While intercepting from above may be common in AMS, the reason why the A/T was idle in that flight was NOT because of intercepting from above, but because the throttle retarded as its logic told it to do thinking it was on ground as it was indicating -8 (number by recall, sorry if slightly off).
Resultant the crash, all 737 crews were made aware of the existing system limitations and relationship between the A/T and RA1, which until then was only known to the few who had in-depth system knowledge.
Hence when RA1 failed, without a failure flag , but displayed erroneous readings with indications showing the aircraft was on ground (or actually a few feet lower than normal when on ramp), the A/T retarded as programmed to do when RAD ALT <~27ft.
Failure of the operating 3 crew members to monitor the approach and instrumentation led then to a stall situation, the aircraft's autopilot trying to maintain a 3 degree glide path while the engines remained at idle, speed bleeding off... the rest is history.
The accident report is available, please read this before posting your reason as stated (intercepting from above) for failing automatics behaviour which should have been monitored by crew who failed to intervene accordingly.
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Sky job
Yes, I quite agree about the reasons for the Turkish accident.
Just pointing out that capturing from above was a factor....and that it happens often in Cloggie land.
Yes, I quite agree about the reasons for the Turkish accident.
Just pointing out that capturing from above was a factor....and that it happens often in Cloggie land.
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Without wishing to prolong the agony here, 'the intercept from above' DID contribute to the AMS accident since the throttles were closed for some time due to the need to descend more rapidly which to some extent 'masked' the throttle closure due to the RadAlt failure.
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But... The Auto Pilot Said...
Its all about professional level flying and situational awareness. The Pros know what (and and what NOT) to expect from their instruments and how to deal with it. If you're not aware of the potential for glide slope errors, and that your on board automation may not act properly, they you're just not up to standard. Another way to look at it might be, when on final approach, if ANYTHING does not look quite right, get out of there - and figure it out at a safe altitude. I think it is called a GO AROUND. You certainly can demand a do-over, but its smart to claim it before you're over the numbers. Duh? If one is flying at the commercial level, I would hope that you already know this stuff and that you're thinking is generally along the same lines. Being faced with a surprise when crossing the numbers - whatever the situation - is not professional level situational awareness.
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The Turkish 738 accident in AMS was caused by a erroneous Rad Alt driving the Auto Thrust to Idle.
There is an aviation commandment from way back in the early 1900's that goes like this - "Often shalt thou confirm thine airspeed on final, lest the earth rise up and smite thee."
10 commandments of Flying
https://www.ittc.ku.edu/~evans/stuff/commandments.html
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OK,
One of the beauties of GLS is that it is a signal, not multiple beams. The signal can broadcast whatever you tell it too, even curves.
If the OAT gets too high, ATC can clear the ac for a different channel with a GP of 2.8 instead of 3. This is important with CAT III autoland.
Right now, most GLS procedures have 5 channels set up with different GPA's. (when I say most, that means the ones I have designed) (2.5,2.8,3.0,3.1,3.5)
This was to account for aircraft types, and also be used for temp extremes. Heavies are brought in at 2.8, while mediums at 3.0, and lights at 3.1 for wake sep. (guess a bit too much forward thinking there)
So, that is how temperature can be addressed.
No fly zone, yes, exactly, it appears they turned to short final 1000 feet high, theres the GA right there.
One of the beauties of GLS is that it is a signal, not multiple beams. The signal can broadcast whatever you tell it too, even curves.
If the OAT gets too high, ATC can clear the ac for a different channel with a GP of 2.8 instead of 3. This is important with CAT III autoland.
Right now, most GLS procedures have 5 channels set up with different GPA's. (when I say most, that means the ones I have designed) (2.5,2.8,3.0,3.1,3.5)
This was to account for aircraft types, and also be used for temp extremes. Heavies are brought in at 2.8, while mediums at 3.0, and lights at 3.1 for wake sep. (guess a bit too much forward thinking there)
So, that is how temperature can be addressed.
No fly zone, yes, exactly, it appears they turned to short final 1000 feet high, theres the GA right there.