great instrument cross checks!!!!!
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Ashling
No, my math is correct - height + elevation.
For QNH - 13 x 3(00) = 3900 + AD elevation (750 for cash) = 4650
For QFE - 13 x 3(00) = 3900
For 1013 - 4650 +/- 30' per millibar (not that it should matter if you are still at a FL)
So the hardest sum this crew would have had to do is 13 x 3(00) + 750(ish). This level of mental math should easily be attainable by anyone entrusted with a 767 and all the lives therein.
BTW I'm pretty sure the frozen ADI scenario came about as a result of the Korean (?) 747 that flipped on it's back and crashed at Stansted a few years ago. The captains ADI was faulty and had been referred to engineers at STN. It didn't get fixed, captain took the aircraft anyway and launched into the murk... standard Asian command gradient took over and neither the F/O or the engineer seriously challenged the captain as the aircraft turned on it's side and descended. I was en-route to LCY that day and saw the enormous flash through the clouds as it hit. Nasty. We instituted that scenario in the sim just after the report was published. BTW all the above is from memory so the facts may be slightly different
BTW for really interesting tailwind fun and games, try Chambery or Calvi...
No, my math is correct - height + elevation.
For QNH - 13 x 3(00) = 3900 + AD elevation (750 for cash) = 4650
For QFE - 13 x 3(00) = 3900
For 1013 - 4650 +/- 30' per millibar (not that it should matter if you are still at a FL)
So the hardest sum this crew would have had to do is 13 x 3(00) + 750(ish). This level of mental math should easily be attainable by anyone entrusted with a 767 and all the lives therein.
BTW I'm pretty sure the frozen ADI scenario came about as a result of the Korean (?) 747 that flipped on it's back and crashed at Stansted a few years ago. The captains ADI was faulty and had been referred to engineers at STN. It didn't get fixed, captain took the aircraft anyway and launched into the murk... standard Asian command gradient took over and neither the F/O or the engineer seriously challenged the captain as the aircraft turned on it's side and descended. I was en-route to LCY that day and saw the enormous flash through the clouds as it hit. Nasty. We instituted that scenario in the sim just after the report was published. BTW all the above is from memory so the facts may be slightly different
BTW for really interesting tailwind fun and games, try Chambery or Calvi...
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Remoak
Sorry mate, re-read your earlier post you wrote.
13 times 3(00) =3900
3900-750=3150
Very different to what you just wrote which is correct.
"No excuse's, just lessons"
Sorry mate, re-read your earlier post you wrote.
13 times 3(00) =3900
3900-750=3150
Very different to what you just wrote which is correct.
"No excuse's, just lessons"
Some decades ago when training for my IR, the drill was to watch the glideslope needle on its way down and pull power / drop the gear as you reached the glideslope, all the time hand flying.
You then cross-checked the crossing height at the OM, but here it's a DME fix. In any case, below that crossing height before the FAF was a major no-no.
Now the autopilot does it all for you once the approach is selected from the FMS and APP is armed.
In Youtube, the crew is a bit out of the loop while being led down the garden path by a false glideslope and it takes them a little while to get back in, fortunately before anything gets in the way.
Do the SOPs for ILS approaches these days require you to remain above the glideslope crossing height (or very little below it) until the FAF?
You then cross-checked the crossing height at the OM, but here it's a DME fix. In any case, below that crossing height before the FAF was a major no-no.
Now the autopilot does it all for you once the approach is selected from the FMS and APP is armed.
In Youtube, the crew is a bit out of the loop while being led down the garden path by a false glideslope and it takes them a little while to get back in, fortunately before anything gets in the way.
Do the SOPs for ILS approaches these days require you to remain above the glideslope crossing height (or very little below it) until the FAF?
Tend to agree with the comments posted about not checking the DME/Alt earlier, HOWEVER the video is for the benefit of safety so we shouldn't be to harsh.
For those who can't believe that airports exist without radar, there are many places in Australia which have numerous jet departures a day (usually all within 10 minutes of each other
) which have no radar and no control tower. Some only have a NDB as the approach. Good fun when the weather's crook!! 
For those who can't believe that airports exist without radar, there are many places in Australia which have numerous jet departures a day (usually all within 10 minutes of each other
) which have no radar and no control tower. Some only have a NDB as the approach. Good fun when the weather's crook!!
Do the SOPs for ILS approaches these days require you to remain above the glideslope crossing height (or very little below it) until the FAF?
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Ashling
Yeah that was the first post where I was talking about height, the one I was referring to was this one:-
...which is correct.
We should stop this before the thread police get annoyed!
Sorry mate, re-read your earlier post you wrote.
13 times 3(00) =3900
3900-750=3150
13 times 3(00) =3900
3900-750=3150
The math is still simple - 13 x 3(00) gives you height above the airfield, if operating QNH just add the elevation and voila! If using QFE it's very simple, if you are still at a FL at 13 miles (which you could be in parts of Europe) the problem is a little harder, but not much.
...which is correct.
We should stop this before the thread police get annoyed!
Woz, the approach chart shows 3 mi from the 12 DME arc to the glideslope intercept point at 7.5 DME the ILS -- note that the DME arc is on the VOR which may call for some DME switching. The report http://www.caa.govt.nz/Occurrences/00-2518.htm mentions that they used the 15 DME arc to accommodate their speed. Charts on pg 53-54 of the report.
At 220 kt. they were some 1.6 minutes from expected glideslope intercept.
At 220 kt. they were some 1.6 minutes from expected glideslope intercept.
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Ok but I still can't figure where the 3150 figure comes from unless you apply the elevation incorrectly.
It is of course simple math, but under pressure the simple can become tricky sometimes impossable. Its called capacity and not all of us have equal amounts of it. Lack of it in a given situation can rob us of the sa we need to solve it and get back on top. We can all emphasize with the hanging onto the tail of the aircraft feeling. Thats not meant as an excuse just a reason why sometimes people under pressure get it wrong or press on with a bad or deteriorating situation when they should bin it particularly if they task focused or what looks like a form of target fixation with speed control rather than take in the bigger picture.
In this case they go from being ahead of the jet upto capture to being behind it as things start to go wrong. Something that came as a surprise to them and something they were not prepared for. I don't think they even tried to cross check the alt initialy but focused on sorting out the speed. Thankfully they eventually caught up. It almost looks like they all have individual thinks bubbles saying somethings wrong but no one is quite putting their finger on it or prioritising correctly or linking in with the others. Then they all realise at the same point. Maybe if they'd prioritised better as a crew they would have gone around much earlier. The Capt could have directed a cross check from the co or jumpseater and either of them could have voiced concern at an earlier stage.
At the end of the day if it is running away and the world is closing in on you you have to take decisive action especially if close to the ground. They did that in the end.
Does anyone know if they captured the glideslope at the correct range or were they too far out ?
It is of course simple math, but under pressure the simple can become tricky sometimes impossable. Its called capacity and not all of us have equal amounts of it. Lack of it in a given situation can rob us of the sa we need to solve it and get back on top. We can all emphasize with the hanging onto the tail of the aircraft feeling. Thats not meant as an excuse just a reason why sometimes people under pressure get it wrong or press on with a bad or deteriorating situation when they should bin it particularly if they task focused or what looks like a form of target fixation with speed control rather than take in the bigger picture.
In this case they go from being ahead of the jet upto capture to being behind it as things start to go wrong. Something that came as a surprise to them and something they were not prepared for. I don't think they even tried to cross check the alt initialy but focused on sorting out the speed. Thankfully they eventually caught up. It almost looks like they all have individual thinks bubbles saying somethings wrong but no one is quite putting their finger on it or prioritising correctly or linking in with the others. Then they all realise at the same point. Maybe if they'd prioritised better as a crew they would have gone around much earlier. The Capt could have directed a cross check from the co or jumpseater and either of them could have voiced concern at an earlier stage.
At the end of the day if it is running away and the world is closing in on you you have to take decisive action especially if close to the ground. They did that in the end.
Does anyone know if they captured the glideslope at the correct range or were they too far out ?
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I'm not aircrew but had a look at the video (short version).
Congrats to ANZ for the approach they made to help make sure others don't fall into the same trap. (yes pun was intended)
Well done Guys.
clicker
Congrats to ANZ for the approach they made to help make sure others don't fall into the same trap. (yes pun was intended)
Well done Guys.
clicker
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For those who've watched the second video - the fact that a failure of the glideslope sidelobe transmitter will always lead to an erroneous and potentially very dangerous "on glideslope" indication is frightening. Equipment, whenever possible, should of course be fail-safe.
In this case, a failure of the sidelobe transmitter should result in a shutdown of the main transmitter. So why doesn't it?
(Perhaps this should be discussed in the Tech Forum?)
Wile E. Coyote
B.Sc. Electronics
In this case, a failure of the sidelobe transmitter should result in a shutdown of the main transmitter. So why doesn't it?
(Perhaps this should be discussed in the Tech Forum?)
Wile E. Coyote
B.Sc. Electronics
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4PW's
Aye well a lot of things aren't clear in this life... like what exactly Ashling was referring to when he mentioned a "13nm check". Could be QFE, could be QNH, could be a FL. I was just covering all the bases!
Anyway, the use of QFE is generally up to the operator, not the airport or nation involved. Even the Russians will pass you a QFE if you ask nicely. You can always figure it out yourself if they won't. Not sure why you would want to though, unless you were one of those ex-RAF handlebar-moustache types! Not sure what Air NZ use, probably QNH though.
Aye well a lot of things aren't clear in this life... like what exactly Ashling was referring to when he mentioned a "13nm check". Could be QFE, could be QNH, could be a FL. I was just covering all the bases!
Anyway, the use of QFE is generally up to the operator, not the airport or nation involved. Even the Russians will pass you a QFE if you ask nicely. You can always figure it out yourself if they won't. Not sure why you would want to though, unless you were one of those ex-RAF handlebar-moustache types! Not sure what Air NZ use, probably QNH though.
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Hi Remoak
The purpose of my 13nm elevation 763ft runway elevation question was not to illicit a mathematical answer as it should be easy in front of a computer. The purpose was to generate thought about how easy it would be under pressure when capacity is sapped.
This is a subject the report, that ratherbeflying kindly referred us to, dwells on in some depth.
Your quite right I did not specify QFE or QNH. I assumed QNH. I apologise for the lack of clarity in my question.
The reason I have persisted questioning you on this is because you stated that it was all very easy but you gave the wrong answer. Lets look at your math in post 32.
13 times 3(00) = 3900 no snag, accurate QFE check for 13nm.
3900-750(763 rounded)=3150 snag.
It can't be QFE, thats 3900
It can't be QNH as thats 4650. 3900 PLUS elevation. In post 41 you actually change your answer to this but you can't have it both ways.
It can't be 1013 as neither you or I gave a pressure setting so where the dickens does 3150 come from. My fear is I'm missing something basic, if so I'd like to know so I learn.
Take care and fly safe
The purpose of my 13nm elevation 763ft runway elevation question was not to illicit a mathematical answer as it should be easy in front of a computer. The purpose was to generate thought about how easy it would be under pressure when capacity is sapped.
This is a subject the report, that ratherbeflying kindly referred us to, dwells on in some depth.
Your quite right I did not specify QFE or QNH. I assumed QNH. I apologise for the lack of clarity in my question.
The reason I have persisted questioning you on this is because you stated that it was all very easy but you gave the wrong answer. Lets look at your math in post 32.
13 times 3(00) = 3900 no snag, accurate QFE check for 13nm.
3900-750(763 rounded)=3150 snag.
It can't be QFE, thats 3900
It can't be QNH as thats 4650. 3900 PLUS elevation. In post 41 you actually change your answer to this but you can't have it both ways.
It can't be 1013 as neither you or I gave a pressure setting so where the dickens does 3150 come from. My fear is I'm missing something basic, if so I'd like to know so I learn.
Take care and fly safe
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Richard Dawkins faced this very thing at a Cambridge conference on science and religion.
He was very pointed in his questioning of the theologians present, which to them was 'very 19th Century'.
What they essentially meant was 'it is impolite to ask such direct, factual questions of (religious) people today', because it is embarrassing!
Nonetheless, Ashling has persisted, as Mr Dawkins persisted.
remoak, you duffed it.
You duffed it just like anyone else who rushes maths duffes it, my daughter included.
Give over, mate.
Don't be overly embarrassed.
It's not a slight on your name, merely confirmation that Ashling has a very valid point.
He was very pointed in his questioning of the theologians present, which to them was 'very 19th Century'.
What they essentially meant was 'it is impolite to ask such direct, factual questions of (religious) people today', because it is embarrassing!
Nonetheless, Ashling has persisted, as Mr Dawkins persisted.
remoak, you duffed it.
You duffed it just like anyone else who rushes maths duffes it, my daughter included.
Give over, mate.
Don't be overly embarrassed.
It's not a slight on your name, merely confirmation that Ashling has a very valid point.
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Chaps, chaps, chaps... so quick to accuse. No matter... I forgive you.
3150 is what you get if you assume a standard ICAO day... I think the term used to be "absolute height". It is what you get if you have 1013 on your subscale on that standard day. To get your height above the aerodrome, you take your 3900' and subtract the field elevation 750'(rounded) - which gives you 3150 (rounded). That is your height above the ground on a standard day with 1013 set. You then make an "altitude/pressure correction at your discretion" - which is what I said way back in post #32.
So you can see that my math is not wrong, it's just a different way of looking at it.
I'm afraid that no actual duffing has occurred. I am, in fact, completely over it, and embarassment has not been a feature of my life these past few days.
I basically agree with Ashling, but where we differ is that I think that any pilot who finds himself in charge of a 767 over an oceanic sector should not be fazed by such simple calculations. There is plenty of time to figure it out, he has a First Officer and an autopilot to help him, presumably the 767 has EFIS and some sort of VNAV capability. Fatigue should not be a factor as it is a relatively short sector.
In my view (and this is something I have done throughout my flying career), any captain should have a clear mental picture of where he is and what he should expect to see during the approach. You don't start thinking about tailwinds or other factors once you are on the approach, you consider it beforehand and brief accordingly.
Again, in my view, these guys got complacent, and once it all started to unravel, got pushed into a corner. They lost SA, and instead of doing what they SHOULD have done (missed approach), they persisted, and very nearly paid the price. Nobody likes to go around and be thought a bit of a charlie, but then nobody likes to impale themselves on an island either. To me, this is more about professional pride than any other combination of stressors.
It is quite true that we can all screw up under pressure, but the trick is to make sure that we always "fail safe". If at any time during an approach you are not 100% sure of your horizontal or vertical position, just go around. If these guys had done that, there would have been no drama (or video for that matter).
Anyway, the math is correct (or is it...?)
3150 is what you get if you assume a standard ICAO day... I think the term used to be "absolute height". It is what you get if you have 1013 on your subscale on that standard day. To get your height above the aerodrome, you take your 3900' and subtract the field elevation 750'(rounded) - which gives you 3150 (rounded). That is your height above the ground on a standard day with 1013 set. You then make an "altitude/pressure correction at your discretion" - which is what I said way back in post #32.
So you can see that my math is not wrong, it's just a different way of looking at it.
I'm afraid that no actual duffing has occurred. I am, in fact, completely over it, and embarassment has not been a feature of my life these past few days.
I basically agree with Ashling, but where we differ is that I think that any pilot who finds himself in charge of a 767 over an oceanic sector should not be fazed by such simple calculations. There is plenty of time to figure it out, he has a First Officer and an autopilot to help him, presumably the 767 has EFIS and some sort of VNAV capability. Fatigue should not be a factor as it is a relatively short sector.
In my view (and this is something I have done throughout my flying career), any captain should have a clear mental picture of where he is and what he should expect to see during the approach. You don't start thinking about tailwinds or other factors once you are on the approach, you consider it beforehand and brief accordingly.
Again, in my view, these guys got complacent, and once it all started to unravel, got pushed into a corner. They lost SA, and instead of doing what they SHOULD have done (missed approach), they persisted, and very nearly paid the price. Nobody likes to go around and be thought a bit of a charlie, but then nobody likes to impale themselves on an island either. To me, this is more about professional pride than any other combination of stressors.
It is quite true that we can all screw up under pressure, but the trick is to make sure that we always "fail safe". If at any time during an approach you are not 100% sure of your horizontal or vertical position, just go around. If these guys had done that, there would have been no drama (or video for that matter).
Anyway, the math is correct (or is it...?)
Remoak,
Under what circumstances would you be 3150' above airfield elevation on slope at 13 DME?
Or,
Under what circumstances would your altimiter read 3150' if you were on slope at 13 DME to an airfield 763' above sea level?
QNH you'd have 4663' on the altimeter
QFE you'd have 3900' on the altimeter
QNE you'd have 4663' +/- correction for local pressure.
In all cases you'd be 3900' above the airfield.
Again, where does 3150' come into it? And do you agree that a simple altimeter check can be made in error in the heat of the moment?
Under what circumstances would you be 3150' above airfield elevation on slope at 13 DME?
Or,
Under what circumstances would your altimiter read 3150' if you were on slope at 13 DME to an airfield 763' above sea level?
QNH you'd have 4663' on the altimeter
QFE you'd have 3900' on the altimeter
QNE you'd have 4663' +/- correction for local pressure.
In all cases you'd be 3900' above the airfield.
Again, where does 3150' come into it? And do you agree that a simple altimeter check can be made in error in the heat of the moment?