great instrument cross checks!!!!!
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Maui
I'm truly sorry to hear about your daughters accident and wish her and you all the best as she recovers.
My comments re driving were meant to be a bit tounge in cheek, as most of us have disobeyed the rules at some point, and you raised the sunject. Had I known of your daughters incident I would not have made them.
As I have said before I agree with much of what you say but I still don't agree with your definition of deliberate and I dislike your need to shout or use a profanity to try and give force to your argument. In my view it does you a disservice and actually detracts from your arguement.
Best regards
I'm truly sorry to hear about your daughters accident and wish her and you all the best as she recovers.
My comments re driving were meant to be a bit tounge in cheek, as most of us have disobeyed the rules at some point, and you raised the sunject. Had I known of your daughters incident I would not have made them.
As I have said before I agree with much of what you say but I still don't agree with your definition of deliberate and I dislike your need to shout or use a profanity to try and give force to your argument. In my view it does you a disservice and actually detracts from your arguement.
Best regards
Deliberate act: Reaching the minima, recognising that you are at the minima, recognising that you are still in the murk, descending anyway.
Non deliberate act: Losing situational awareness because unexpected things are happening, realising too late that you are below the minima, conducting a go-around.
Or to put it more in terms of this incident,
Deliberate act: Descending on glide-slope below the min intercept altitude without an altitude check because "she'll be right mate, we're on a you-beaut ILS thingo."
Non deliberate act: Descending on glide-slope below the min intercept altitude because you've lost the plot.
In my humbly uninformed opinion, the Air NZ crew lost the plot for a certain amount of time AND they probably didn't give the altitude check enough importance. As someone said above, one of the first things you think when the numbers don't add up, is that you've done the sums wrong (and as Remoak nicely showed, it is easy to do.) Although everyone would probably agree that you should go-around as soon as you have some inkling that something is wrong, in real life it may take several seconds for it to all sink in.
It doesn't make it right or excusable, but it's also not necessarily deliberate.
Non deliberate act: Losing situational awareness because unexpected things are happening, realising too late that you are below the minima, conducting a go-around.
Or to put it more in terms of this incident,
Deliberate act: Descending on glide-slope below the min intercept altitude without an altitude check because "she'll be right mate, we're on a you-beaut ILS thingo."
Non deliberate act: Descending on glide-slope below the min intercept altitude because you've lost the plot.
In my humbly uninformed opinion, the Air NZ crew lost the plot for a certain amount of time AND they probably didn't give the altitude check enough importance. As someone said above, one of the first things you think when the numbers don't add up, is that you've done the sums wrong (and as Remoak nicely showed, it is easy to do.) Although everyone would probably agree that you should go-around as soon as you have some inkling that something is wrong, in real life it may take several seconds for it to all sink in.
It doesn't make it right or excusable, but it's also not necessarily deliberate.
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you've done the sums wrong (and as Remoak nicely showed, it is easy to do.)
I was going to let this go, but if you must persist...
Using the scenario already discussed:
3150' is your height above the ground with QNH set. You know that at 13D you should be 3900' feet above msl (13 x 3(00)). The difference should equal the elevation.
So why bother with the 3150'?
Mainly because, if you get in the habit of always knowing how far from the ground you are, you will enhance your SA, and later in the approach, you have a point of reference when the radalt starts working at 2500' (depending on terrain of course). That would have been rather helpful to the ANZ crew, I suspect.
Knowing how far above the ground you are is a useful thing. In all the years I spent going in to places like Innsbruck, Calvi, and other similar places, it was the thing I was most interested in (as others who have done those approaches will no doubt understand).
You may not like the check, or understand it, but the math was always correct. It's just a different approach to what you might do, but no less valid.
Wasn't my idea, BTW, taught to me by a crusty old BA captain who reckoned it saved his bacon a few times when banging around in Comets.
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Good luck remoak, no more for me to say on the subject of 13d etc.
How do peoples SOPs stack up to prevent this kind of thing ?
Of course we cannot descend below a procedure minima until allowed by the procedure but in my outfit there is no requirement to verbaly crosscheck range v alt at glideslope capture. Sure we should have the SA and follow the procedure but if it was a verbal crosscheck you were required by SOP to do before you pressed on surely that would be better ? Currently the only compulsery verbal check we have is at the approach fix at around 4 DME.
Also my company practises low drag approach's and has recently changed SOP to delay putting the gear down etc until 1500 above airfield and that tends to clash with the approach fix, is this true of any other operators. I have no issue with it on a visualy monitored approach but if IMC it seems daft to me. Common sense says show airmanship and take the gear earlier if IMC which is what I do but I also see some treat it as a target to achieve. Is this a problem elsewhere ?
How do peoples SOPs stack up to prevent this kind of thing ?
Of course we cannot descend below a procedure minima until allowed by the procedure but in my outfit there is no requirement to verbaly crosscheck range v alt at glideslope capture. Sure we should have the SA and follow the procedure but if it was a verbal crosscheck you were required by SOP to do before you pressed on surely that would be better ? Currently the only compulsery verbal check we have is at the approach fix at around 4 DME.
Also my company practises low drag approach's and has recently changed SOP to delay putting the gear down etc until 1500 above airfield and that tends to clash with the approach fix, is this true of any other operators. I have no issue with it on a visualy monitored approach but if IMC it seems daft to me. Common sense says show airmanship and take the gear earlier if IMC which is what I do but I also see some treat it as a target to achieve. Is this a problem elsewhere ?
3150' is your height above the ground with QNH set. You know that at 13D you should be 3900' feet above msl (13 x 3(00)). The difference should equal the elevation.
Otherwise, what happens at 2 DME?
Going by your method you'd be 600' AMSL (2 x 3(00)), and 50' below ground level. So going by your check method, you'd touchdown a little over 2 miles short of the runway.
That is all from me, we'll have to agree to disagree.
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you should be 3900' above the ground
Not much SA on my part eh...
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Jeesis bluddy chryst mate, give up!
We use systems and procedures that have utility for all approaches, everywhere. How does your dumb-ass'd system work when approaching a cliff-faced drop-off airport? And it was ass-about to boot!
I've been very patient, as have most readers, but you're starting to show us all how very, very worrying it is when one person simply cannot throw his hands in the air and utter the simple words, "I was wrong, dudes."
Your maths proves how utterly wrong you are. That's what's great about maths; it's objective. You're now trying to make it subjective by baffling us with bullsheet.
Who gives a toss about a crusty old BA Captain? That's simply a throw away comment for "don't blame me for thinking this, my mate the BA Skipper said it was the go".
You're offending British Airways!
Sorry mate, really I am, but have you thought of getting a new handle?
We use systems and procedures that have utility for all approaches, everywhere. How does your dumb-ass'd system work when approaching a cliff-faced drop-off airport? And it was ass-about to boot!
I've been very patient, as have most readers, but you're starting to show us all how very, very worrying it is when one person simply cannot throw his hands in the air and utter the simple words, "I was wrong, dudes."
Your maths proves how utterly wrong you are. That's what's great about maths; it's objective. You're now trying to make it subjective by baffling us with bullsheet.
Who gives a toss about a crusty old BA Captain? That's simply a throw away comment for "don't blame me for thinking this, my mate the BA Skipper said it was the go".
You're offending British Airways!
Sorry mate, really I am, but have you thought of getting a new handle?
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Looks like you didn't have much luck there remoak.
And thats the thing here isn't it, whether your tired at the end of your 5th early or 3rd transatlantic or have just been put under pressure by the unexpected it is all to easy to get it unintentialy wrong. What seems simple on paper does not always work out that way.
That of course does not excuse the error or diminish it. Thought I'd add that disclaimer, can't think why !
Thats why we need to have robust procedures to counter things hence my query re a compulsery verbalised crosscheck at capture. Any thoughts on that.
We also need to have a clear understanding of what is vital and what is not. In this instance it seems to me the vital was figuring out why the capture had happened so unexpectadly not chasing the speed. If in doubt go-around get safe then sort it. After all they were heading for the ground/sea. Of course easy for me to say now but at least we can carry the lessons for when something happens to us.
Don't change your handle remoak I'd miss you.
And thats the thing here isn't it, whether your tired at the end of your 5th early or 3rd transatlantic or have just been put under pressure by the unexpected it is all to easy to get it unintentialy wrong. What seems simple on paper does not always work out that way.
That of course does not excuse the error or diminish it. Thought I'd add that disclaimer, can't think why !
Thats why we need to have robust procedures to counter things hence my query re a compulsery verbalised crosscheck at capture. Any thoughts on that.
We also need to have a clear understanding of what is vital and what is not. In this instance it seems to me the vital was figuring out why the capture had happened so unexpectadly not chasing the speed. If in doubt go-around get safe then sort it. After all they were heading for the ground/sea. Of course easy for me to say now but at least we can carry the lessons for when something happens to us.
Don't change your handle remoak I'd miss you.
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I've been with my company for 3 years having sported a handlebar moustache for 19 or so years. So my experience of different airlines SOPs is limited. My company has no such crosscheck.
Glad to hear yours does though, sounds sensible to me.
Glad to hear yours does though, sounds sensible to me.
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Yeah mine has the a crosscheck of the approach fix/outer marker which is always verbalised. I think/hope most if not all probably do.
That said we've just changed SOP to take gear and intermediate flap at 1500 aal. Then we are asked to be stable in the landing configuration at 1000 aal. This rather clashes with most approach fixs. Obviously we are not all clones and can exercise airmanship to ensure the check gets done if we're not visual but if you ask me its looking for trouble.
In any case the approach fix check seems all a little bit last gasp as you will probably be only 1200-1500 aal at that point if you have descended at the wrong point then ground seperation would be a tadge tight. Not everyone has EGPWS, we do though. Surely better to have a verbalised check at G/S capture with a requirement to challenge if it isn't made as remoaks outfit do. In this case it would not have prevented the capture but the error would have been much more likely to have been spotted at an early stage.
That said we've just changed SOP to take gear and intermediate flap at 1500 aal. Then we are asked to be stable in the landing configuration at 1000 aal. This rather clashes with most approach fixs. Obviously we are not all clones and can exercise airmanship to ensure the check gets done if we're not visual but if you ask me its looking for trouble.
In any case the approach fix check seems all a little bit last gasp as you will probably be only 1200-1500 aal at that point if you have descended at the wrong point then ground seperation would be a tadge tight. Not everyone has EGPWS, we do though. Surely better to have a verbalised check at G/S capture with a requirement to challenge if it isn't made as remoaks outfit do. In this case it would not have prevented the capture but the error would have been much more likely to have been spotted at an early stage.
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From the aerodrome perspective...
Firstly, many thanks for the links. A salutory lesson.
By coincidence, I'm running a course for new recruits to Airfield Operations and we're covering ILS at the moment. They don't know it yet, but they're going to sit through this video next time we're in the classroom. Our ILS installations have critical areas marked out with fences, posts etc and we teach people NEVER to enter these areas without permission from the Tels guys, not even when cutting grass or chasing intruders on the airfield etc etc. We also teach what the funny little aerials pointing at the Glide & Loc arrays are for - the field monitors and how important they are and not to bash into them.
We have a comprehensive system of Works Permits for ANY work that takes place on the Manoeuvring Area and a 'no blame' culture which encourages reporting of damage or possible contact with any installation.
It is still disturbing, however, to hear that it is possible that our installations may not 'fail-safe'.
Cheers,
TheOddOne
By coincidence, I'm running a course for new recruits to Airfield Operations and we're covering ILS at the moment. They don't know it yet, but they're going to sit through this video next time we're in the classroom. Our ILS installations have critical areas marked out with fences, posts etc and we teach people NEVER to enter these areas without permission from the Tels guys, not even when cutting grass or chasing intruders on the airfield etc etc. We also teach what the funny little aerials pointing at the Glide & Loc arrays are for - the field monitors and how important they are and not to bash into them.
We have a comprehensive system of Works Permits for ANY work that takes place on the Manoeuvring Area and a 'no blame' culture which encourages reporting of damage or possible contact with any installation.
It is still disturbing, however, to hear that it is possible that our installations may not 'fail-safe'.
Cheers,
TheOddOne
The one thing that seems to have been forgotten amongst the dick swinging and maths lessons is that the crew correctly identified a problem (regardless of where the identification took place) and reacted to it in a manner that kept the crew, pax and aircraft safe.
That is all that is important
People can talk about what they would do on checks and how they would calculate altimeter checks, but they can do all of that and still spud an aeroplane into the ground.
It is the people who, by their arrogance, believe that they cannot be wrong who are the worry - I suspect that there may be one or two of that ilk participating in this thread.
The little voice in the head saying something is wrong is a very useful thing...
Both Air NZ and the crew are to be congratulated for allowing their situation to be used as a training aid so that others who don't listen to their "little voice" don't fall for the same trap and not recognise the situation for what it is.
Here endeth the sermon...
That is all that is important
People can talk about what they would do on checks and how they would calculate altimeter checks, but they can do all of that and still spud an aeroplane into the ground.
It is the people who, by their arrogance, believe that they cannot be wrong who are the worry - I suspect that there may be one or two of that ilk participating in this thread.
The little voice in the head saying something is wrong is a very useful thing...
Both Air NZ and the crew are to be congratulated for allowing their situation to be used as a training aid so that others who don't listen to their "little voice" don't fall for the same trap and not recognise the situation for what it is.
Here endeth the sermon...
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3150' is your height above the ground with QNH set. You know that at 13D you should be 3900' feet above msl (13 x 3(00)). The difference should equal the elevation.
remoak, after nine days of pondering the answer to a simple altitude/dme glide-slope cross check question, you're still posting complete garbage on the subject. Perhaps you're not actually a pilot, perhaps you're deliberately having a laugh ... or perhaps you truly don't 'get it'. Am I alone in finding that thought really scary?
What you've said here is completely wrong in every respect. 3150' is not your height above the ground with QNH set, for that you'd need to know the elevation of the local terrain. Instead, it's your height above the airfield if the altimeter is reading 3,900' with the QNH set. BUT since, as an approximation, you should actually be at 4,650' at 13d, what on earth is the use of knowing what your height above the airfield would be if you were at some different altitude (and if there is a reason, why do you want to know what it is at an altitude of 3,900' rather than, say, 4,300' or 2,700' or any other random altitude you could select)?
Then, as has already been observed, the 13d cross check is 3,900' above the airfield, not above msl.
Nine days and still getting it completely wrong, allegedly because of lack of sleep! I truly hope that all the tired pilots I fly with can get it right in not much more than nine seconds.
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Nine days and still getting it completely wrong, allegedly because of lack of sleep! I truly hope that all the tired pilots I fly with can get it right in not much more than nine seconds.
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Firstly I admit to not having read every post on this long and educational thread.
Very early in the thread someone made the point that 3 degrees is 324' /nm. Personally I use 320; it's easier on the grey matter. What it ain't is 300'/nm. Thus all the talk about 13nm = 3900' is not quite accurate. It is at least
4160' and could be higher if 324'/nm is correct.
Someone also mentioned awareness and sensing when something is inherently wrong. The fact that they had to use gear & speed brake to stop accelerating on a G/S. Wow! Something was wrong, unless they were at Flap UP. I wonder what the v/s was indicating, and the attitude? Good old power v attitude v v/s. I remember the Airbus Strasburg crash on a rushed VOR/DME approach. They dialled in 3300'/min v/s instead of 3.3fpa. They too pulled the speed brake to try and stop accelerating. All that happened was the power increased to fight the drag. I recall they were at 5 degrees nose down. That was a mighty interesting and very odd attitude to fly a 3.3 degree fpa.
Good to say. in NZ, the bells rang long & loud enough for them to walk away. Good to see they dug a hole, dug it somewhat deeper and them decided to climb out of it; unlike other 'press on regardless' prangs.
Very early in the thread someone made the point that 3 degrees is 324' /nm. Personally I use 320; it's easier on the grey matter. What it ain't is 300'/nm. Thus all the talk about 13nm = 3900' is not quite accurate. It is at least
4160' and could be higher if 324'/nm is correct.
Someone also mentioned awareness and sensing when something is inherently wrong. The fact that they had to use gear & speed brake to stop accelerating on a G/S. Wow! Something was wrong, unless they were at Flap UP. I wonder what the v/s was indicating, and the attitude? Good old power v attitude v v/s. I remember the Airbus Strasburg crash on a rushed VOR/DME approach. They dialled in 3300'/min v/s instead of 3.3fpa. They too pulled the speed brake to try and stop accelerating. All that happened was the power increased to fight the drag. I recall they were at 5 degrees nose down. That was a mighty interesting and very odd attitude to fly a 3.3 degree fpa.
Good to say. in NZ, the bells rang long & loud enough for them to walk away. Good to see they dug a hole, dug it somewhat deeper and them decided to climb out of it; unlike other 'press on regardless' prangs.
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Quote:
Well as a matter of fact, using the international standard of 1nm=6080ft, 1d slant range equates to 318ft. But since the earth is not a sphere, it is actually 316ft at the equator and 320ft at the poles (all figures to the nearest whole foot).
All of which is stupendously unimportant. 300ft per nm is far easier on the grey matter and quite good enough for all practical cross-check purposes!
Very early in the thread someone made the point that 3 degrees is 324' /nm. Personally I use 320; it's easier on the grey matter. What it ain't is 300'/nm. Thus all the talk about 13nm = 3900' is not quite accurate. It is at least
4160' and could be higher if 324'/nm is correct
4160' and could be higher if 324'/nm is correct
All of which is stupendously unimportant. 300ft per nm is far easier on the grey matter and quite good enough for all practical cross-check purposes!
Grandpa Aerotart
Anyone have any thoughts on why the speed was running away when they seem to be flying a very flat low approach....400'/8DME?
Completely understandable if they intercepted a higher false glideslope lobes but more difficult to comprehend in these circumstances.
While I currently fly the 7673 I flew F28s for some years around the same sorts of Pacific Island destos as Apia (although not actually Apia) so black hole approaches, nil radar, useless ATC, un monitored aids, not recently calibrated aids and NBD or twin locator approaches way more often than ILS or VOR etc was just the daily grind...and VERY high terrain.
DME/Dist awareness was a highly refined art at that airline, drummed into us from day 1 and all via mental maths...every IAL procedure and every runway had it's own individual profile and we were expected to apply them even on a visual approach...it doesn't seem to be at many airlines...we actually used to do DME homing and DME letdowns for real...the ultimate non precision approach
We even had to know how to calculate limiting steps and estimate a runway profile by glancing at the 10-9 and eyeballing where the DME was in relation to the desired threshold
Sorry remeok, 3 x dist + elevation. QNE is a non starter and QFE (in an IAL procedure) used in so few places as to be irrelevant to the discussion. The only place I ever used it was backwoods mainland China in command of a Bizjet and it was about the most terrifying thing I have done in a jet...hole and digging springs to mind.
DME/Alt glideslope checks very heavily emphasized where I work now and we are never off the beaten track like this crew.
Bottom line is they caught it before it was fatal...more power to them...and I bet DME/Alt checks are a REAL big deal at AN now
Completely understandable if they intercepted a higher false glideslope lobes but more difficult to comprehend in these circumstances.
While I currently fly the 7673 I flew F28s for some years around the same sorts of Pacific Island destos as Apia (although not actually Apia) so black hole approaches, nil radar, useless ATC, un monitored aids, not recently calibrated aids and NBD or twin locator approaches way more often than ILS or VOR etc was just the daily grind...and VERY high terrain.
DME/Dist awareness was a highly refined art at that airline, drummed into us from day 1 and all via mental maths...every IAL procedure and every runway had it's own individual profile and we were expected to apply them even on a visual approach...it doesn't seem to be at many airlines...we actually used to do DME homing and DME letdowns for real...the ultimate non precision approach
We even had to know how to calculate limiting steps and estimate a runway profile by glancing at the 10-9 and eyeballing where the DME was in relation to the desired threshold
Sorry remeok, 3 x dist + elevation. QNE is a non starter and QFE (in an IAL procedure) used in so few places as to be irrelevant to the discussion. The only place I ever used it was backwoods mainland China in command of a Bizjet and it was about the most terrifying thing I have done in a jet...hole and digging springs to mind.
DME/Alt glideslope checks very heavily emphasized where I work now and we are never off the beaten track like this crew.
Bottom line is they caught it before it was fatal...more power to them...and I bet DME/Alt checks are a REAL big deal at AN now
Last edited by Chimbu chuckles; 13th Feb 2007 at 13:49.