Density height calculation question
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Checkboard, drivel.
More bleating from a know-nothing with a grievance
QF trainers include plenty of Pilots who started out in GA and know exactly how to calculate density altitude or a PNR.
But they don’t have to.
Everything nowadays is done on an IPad.
More bleating from a know-nothing with a grievance
QF trainers include plenty of Pilots who started out in GA and know exactly how to calculate density altitude or a PNR.
But they don’t have to.
Everything nowadays is done on an IPad.
Looks like the type of questions haven't changed much since the old DCA SCPL theory exams of the 1950 - 1960's.
I well remember scratching my head around the complexity of gyro steering questions centred on the South Pole. After joining DCA in 1969 my office was next to Ted Steele the former wartime RAAF navigator who set the SCPL navigation and flight planning exams in those days. He came across as an embittered old man who hated pilots for some reason. I tackled him on the uselessness of South Pole gyro steering questions for the average GA charter pilot flying Chieftains to Tasmania which was SFA. He said the SCPL exams were first vetted and approved by Qantas as that was the standard demanded of Qantas recruits. That could be an urban myth but it came from the horse's mouth so to speak.
I well remember scratching my head around the complexity of gyro steering questions centred on the South Pole. After joining DCA in 1969 my office was next to Ted Steele the former wartime RAAF navigator who set the SCPL navigation and flight planning exams in those days. He came across as an embittered old man who hated pilots for some reason. I tackled him on the uselessness of South Pole gyro steering questions for the average GA charter pilot flying Chieftains to Tasmania which was SFA. He said the SCPL exams were first vetted and approved by Qantas as that was the standard demanded of Qantas recruits. That could be an urban myth but it came from the horse's mouth so to speak.
I'll always remember Question 1 in SCPL Nav was a Mer. Parts question , Co-ordinates of Sydney and Nadi given, come up with track and distance, or working backwards from landing weight limit, Mid zone weights etc, took ages in Flight Planning and was never going to be of any practical use in the time of INS and modern procedures.
Interesting enough 20 years later I had to do the British CAA ATPL subjects and they were even more irrelevant, the met was based around BOAC routes and the various phenomena they would encounter in Bristol Brabazons or the like.
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Experience airline pilots usually don’t give a toss on how to calculate the density altitude. Most probably they forgot how to. As long as you remember higher temperature = higher density altitude. That’s good enough. I still remember tho but never I had to use it unless for CPL/ATPL exams back in the days.
PPRuNe Handmaiden
To be qualified to fly to LSZS Samedan FOCA (Swiss Authorities) insist every IFR pilot do an online test every year (as well as simulator refresher). One of the questions is to calculate Density Height.
Engadin Airport St. Moritz Airlines: News
Engadin Airport St. Moritz Airlines: News
Samedan, isn’t that one of the loveliest approaches in winter? Sure brings back fond memories of 20 years ago when flying used to be fun with lots of empty positioning legs in the Falcon.
I read threads like these and thank goodness that I’m a dinosaur who was lucky enough to fly in an era when it was meant to be fun.
Requiring someone to calculate Density Height to a nonsensical level of precision answers more questions about the sanity of the person setting the question than he/she would like.
Out of curiosity, does the ATPL syllabus here now include Altimeter Temperature Error Correction? That’s one area where calculation to a decent level of precision makes sense. I don’t recall learning this in 1971, presumably the esteemed polar navigator at DCA never knew about this either.
I read threads like these and thank goodness that I’m a dinosaur who was lucky enough to fly in an era when it was meant to be fun.
Requiring someone to calculate Density Height to a nonsensical level of precision answers more questions about the sanity of the person setting the question than he/she would like.
Out of curiosity, does the ATPL syllabus here now include Altimeter Temperature Error Correction? That’s one area where calculation to a decent level of precision makes sense. I don’t recall learning this in 1971, presumably the esteemed polar navigator at DCA never knew about this either.
Moderator
Perhaps one might view things through slightly differently coloured glasses ?
I would submit that there is no reason for the theory exams to be "practical" - that's more the province of endorsement checkouts, line checks, local proficiency checks and so forth. I well recall a fairly standard mantra at Ansett back when: "you have to do the course exams but we aren't too worried about them (provided you pass). If you need to fail, that is the role of the check captain during, or at the end of, the endorsement program".
Perhaps the theory exams are to check that the candidate has actually read the books, has done a few practice calculations, and maybe, just maybe, has a bit of an idea of what's what with, and in, the subject material ?
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ...
I would submit that there is no reason for the theory exams to be "practical" - that's more the province of endorsement checkouts, line checks, local proficiency checks and so forth. I well recall a fairly standard mantra at Ansett back when: "you have to do the course exams but we aren't too worried about them (provided you pass). If you need to fail, that is the role of the check captain during, or at the end of, the endorsement program".
Perhaps the theory exams are to check that the candidate has actually read the books, has done a few practice calculations, and maybe, just maybe, has a bit of an idea of what's what with, and in, the subject material ?
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ...
Perhaps one might view things through slightly differently coloured glasses ?
I would submit that there is no reason for the theory exams to be "practical" - that's more the province of endorsement checkouts, line checks, local proficiency checks and so forth. I well recall a fairly standard mantra at Ansett back when: "you have to do the course exams but we aren't too worried about them (provided you pass). If you need to fail, that is the role of the check captain during, or at the end of, the endorsement program".
Perhaps the theory exams are to check that the candidate has actually read the books, has done a few practice calculations, and maybe, just maybe, has a bit of an idea of what's what with, and in, the subject material ?
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ...
I would submit that there is no reason for the theory exams to be "practical" - that's more the province of endorsement checkouts, line checks, local proficiency checks and so forth. I well recall a fairly standard mantra at Ansett back when: "you have to do the course exams but we aren't too worried about them (provided you pass). If you need to fail, that is the role of the check captain during, or at the end of, the endorsement program".
Perhaps the theory exams are to check that the candidate has actually read the books, has done a few practice calculations, and maybe, just maybe, has a bit of an idea of what's what with, and in, the subject material ?
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ...
The shame of it is there were topics /subjects that could have been studied that would have provided some practical value for pilots, e.g.. what the poms call performance A and many other topics to the same academic level.
Perhaps the theory exams are to check that the candidate has actually read the books, has done a few practice calculations, and maybe, just maybe, has a bit of an idea of what's what with, and in, the subject material ?
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ..
That some of the questions get into the bowels of pedantry is unfortunate but that is an unfortunate sideline of the game, I guess ..
Might as well had the students do a quick course on brain surgery.
Moderator
for the most part ATPL/SCPL exams were just an academic exercise
I think we are speaking at cross purposes. I take quite a different point of view - the theory exams are there to test the candidate's ability to demonstrate a knowledge level. So far as any academic level might be concerned, the difficulty of the material was (and still is) reasonably straightforward across the exam set. Getting the exam pass, on the other hand, is in the hard yards realm for most folks due to the rigid pass mark and an often critical time limit for most. Whether one might think the exams are a waste of time or not is moot as they are not likely to disappear into the night air any time soon.
as Centaurus mentions they were set by a chap from a bygone era who wouldn't or couldn't let go.
I did my exams just after Ted's time in the chair. Over the years we have had a considerable number of folks administer the exams, some good, some not so good. Overall, though, for those who put in the effort, the pass came. If I hark back to the 70s/80s I was reasonably heavily involved in theory training and I can recall (with great fondness) several chaps who were not brilliant students by any stretch of the imagination. However, their application and hard work was laudable and the various passes came their way progressively. The examiner, really, is not critical to gaining the pass - the exams have been somewhat similar over the years. Having recently returned to theory training work, although the subjects have changed somewhat, the general style and difficulty of question hasn't to any significant extent. Same, same .. put in the hard yards and the pass is there for the taking.
what the poms call performance A and many other topics to the same academic level.
Having a performance engineering background, I am quite familiar with Perf A. The Australian syllabus has always presumed that the stuff be covered albeit that the exams have never, to any significant extent, addressed the certification work and its application to airline performance scheduling. While there is no reason why a pilot can't acquire a very sound level of knowledge in the work (Centaurus, whom I have known very well for many, many years is a case in point) the reality is that the airlines have (or should have access to) appropriate engineering folk who can do the work on behalf of the pilot folks.
they had to study pressurisation and 767 systems for a ATPL(H)
I can only agree with your thoughts there, good sir. DRW still to your liking, one trusts ?
I think we are speaking at cross purposes. I take quite a different point of view - the theory exams are there to test the candidate's ability to demonstrate a knowledge level. So far as any academic level might be concerned, the difficulty of the material was (and still is) reasonably straightforward across the exam set. Getting the exam pass, on the other hand, is in the hard yards realm for most folks due to the rigid pass mark and an often critical time limit for most. Whether one might think the exams are a waste of time or not is moot as they are not likely to disappear into the night air any time soon.
as Centaurus mentions they were set by a chap from a bygone era who wouldn't or couldn't let go.
I did my exams just after Ted's time in the chair. Over the years we have had a considerable number of folks administer the exams, some good, some not so good. Overall, though, for those who put in the effort, the pass came. If I hark back to the 70s/80s I was reasonably heavily involved in theory training and I can recall (with great fondness) several chaps who were not brilliant students by any stretch of the imagination. However, their application and hard work was laudable and the various passes came their way progressively. The examiner, really, is not critical to gaining the pass - the exams have been somewhat similar over the years. Having recently returned to theory training work, although the subjects have changed somewhat, the general style and difficulty of question hasn't to any significant extent. Same, same .. put in the hard yards and the pass is there for the taking.
what the poms call performance A and many other topics to the same academic level.
Having a performance engineering background, I am quite familiar with Perf A. The Australian syllabus has always presumed that the stuff be covered albeit that the exams have never, to any significant extent, addressed the certification work and its application to airline performance scheduling. While there is no reason why a pilot can't acquire a very sound level of knowledge in the work (Centaurus, whom I have known very well for many, many years is a case in point) the reality is that the airlines have (or should have access to) appropriate engineering folk who can do the work on behalf of the pilot folks.
they had to study pressurisation and 767 systems for a ATPL(H)
I can only agree with your thoughts there, good sir. DRW still to your liking, one trusts ?
PPRuNe Handmaiden
lucille
It sure is. Love a winter approach into there. It's either CAVOK or no go. Simples.
Ahhh the good old temperature correction. Fortunately the Swiss and the Scandi ATC add a temperature correction to the altitude they give you. Rather reassuring with those rocks around. However, our FMS has a temperature correction function. Saves a lot of brain work. (Temp correction is another thing FOCA test you on for Samedan. FOCA also test your knowledge about Föhn winds too.)
Have you done Sion LSGS too?
So - I guess the point is that you just never know when you're going to need to know how to do some of these calculations - or at least know where to look it up.
It sure is. Love a winter approach into there. It's either CAVOK or no go. Simples.
Ahhh the good old temperature correction. Fortunately the Swiss and the Scandi ATC add a temperature correction to the altitude they give you. Rather reassuring with those rocks around. However, our FMS has a temperature correction function. Saves a lot of brain work. (Temp correction is another thing FOCA test you on for Samedan. FOCA also test your knowledge about Föhn winds too.)
Have you done Sion LSGS too?
So - I guess the point is that you just never know when you're going to need to know how to do some of these calculations - or at least know where to look it up.
No, never went to Sion. My masters preferred St. Moritz. As I recall temp correction only became available on Honeywell’s after I went on the G650. Can barely remember to check the tyres on my Zimmer frame these days let alone what I did 7 years ago.
My point was the irony of requiring us to calculate Density Height to the nearest inch all the while ignoring the existence of the large altimeter errors induced by extreme cold weather within the syllabus of the Senior Comm theory in my era. Made all the more delicious when it was just now revealed that the chap setting the syllabus at that time was a navigator with polar experience.
As my old mate Rummy used to say, “there are unknown unknowns”. You’re 100% correct, it behooves us all to minimise their numbers. Curiosity may have killed the cat, but it never killed a pilot.
My point was the irony of requiring us to calculate Density Height to the nearest inch all the while ignoring the existence of the large altimeter errors induced by extreme cold weather within the syllabus of the Senior Comm theory in my era. Made all the more delicious when it was just now revealed that the chap setting the syllabus at that time was a navigator with polar experience.
As my old mate Rummy used to say, “there are unknown unknowns”. You’re 100% correct, it behooves us all to minimise their numbers. Curiosity may have killed the cat, but it never killed a pilot.
As a 737 and A320 pilot - I never had the luxury of FMS temperature calculations. Just 4 feet per degree above ISA per 1000' in my head.
Sea level airport, at -10ºC (ISA-25ºC) with an ILS minima of 200'. Four times 25 is 100' per 1000, so add 20' to the minima - 220 feet. Doesn't matter much at that height, but the Glide slope check passing at the Outer Marker is 1000' - and you are on an electronic glide, so at 1000' true alt. That means the "Outer Marker, Glide Slope Check OK" call (required in my manual) means a check height seen on the altimeter of 1100'. The platform altitude of 3000' at 10 miles will mean you are acutally flying at 2700' - so won't intercept the glide at 10 DME from the threshold, but at 9 DME-ish - and your terrain clearance is 300' less than indicated. For altitudes more than 5000' above the airport in these conditions, that error starts to exceed 500'. So you don't have 1000' separation from the rocks, but only 500'. And that's the reason that, in Europe at least, for MSAs above 5000' the terrain separation provided on the charts is 2000', not 1000' - it covers winter operations.
I'm using -10ºC here, because our manual only requires the calculation at -10ºC at the destination, and below.
More interestingly for me is in the Summer. Flying into a coastal Spanish airport, at 35ºC on the ground (ISA+20), there are no calculations required in the manual - but the errors have an operational effect not only in checking the glide slope, but also in capturing the GS from the platform altitude - which at these airports is high - four to seven thousand feet - as you are coming over the hills. The chart for Malaga, for instance, has you at 5000' until 14 DME, to intercept the glide. At ISA, that's perfect. At ISA+20, you are flying indicated at 5000', but are actually 400' higher than that (i.e. 5400 True Alt), so you intercept the glide at 15.3 DME or so. Now some pilots will quote the chart limit - and insist that you can't descend until 14 DME, so they will watch the glide slope slip below them, and at 14 DME will be 400' high - typically in these airports with a tail wind. Those are the ingredients for a high-speed rushed approach.
The obvious solution is to brief that you will intercept at 15.3 DME, and head on down at that distance - no problem.
You can't, of course, fly the TRUE alt of 5000' (4600 indicated) - because your ATC traffic separation is based on indicated altimetry. The VFR guy passing below may be at 4000 indicated and you'll infringe their separation...
Sea level airport, at -10ºC (ISA-25ºC) with an ILS minima of 200'. Four times 25 is 100' per 1000, so add 20' to the minima - 220 feet. Doesn't matter much at that height, but the Glide slope check passing at the Outer Marker is 1000' - and you are on an electronic glide, so at 1000' true alt. That means the "Outer Marker, Glide Slope Check OK" call (required in my manual) means a check height seen on the altimeter of 1100'. The platform altitude of 3000' at 10 miles will mean you are acutally flying at 2700' - so won't intercept the glide at 10 DME from the threshold, but at 9 DME-ish - and your terrain clearance is 300' less than indicated. For altitudes more than 5000' above the airport in these conditions, that error starts to exceed 500'. So you don't have 1000' separation from the rocks, but only 500'. And that's the reason that, in Europe at least, for MSAs above 5000' the terrain separation provided on the charts is 2000', not 1000' - it covers winter operations.
I'm using -10ºC here, because our manual only requires the calculation at -10ºC at the destination, and below.
More interestingly for me is in the Summer. Flying into a coastal Spanish airport, at 35ºC on the ground (ISA+20), there are no calculations required in the manual - but the errors have an operational effect not only in checking the glide slope, but also in capturing the GS from the platform altitude - which at these airports is high - four to seven thousand feet - as you are coming over the hills. The chart for Malaga, for instance, has you at 5000' until 14 DME, to intercept the glide. At ISA, that's perfect. At ISA+20, you are flying indicated at 5000', but are actually 400' higher than that (i.e. 5400 True Alt), so you intercept the glide at 15.3 DME or so. Now some pilots will quote the chart limit - and insist that you can't descend until 14 DME, so they will watch the glide slope slip below them, and at 14 DME will be 400' high - typically in these airports with a tail wind. Those are the ingredients for a high-speed rushed approach.
The obvious solution is to brief that you will intercept at 15.3 DME, and head on down at that distance - no problem.
You can't, of course, fly the TRUE alt of 5000' (4600 indicated) - because your ATC traffic separation is based on indicated altimetry. The VFR guy passing below may be at 4000 indicated and you'll infringe their separation...
PPRuNe Handmaiden
So the answer to post #1 is still B?
Now you know what it's like in the Checkers/reddo household. 
I am probably going to embarrass myself now, but I have a mental block with the ISA deviation calculation in the original question. Everyone is using the PH to calculate ISA deviation at Echo. I don't see (or have forgotten) how pressure affects the lapse rate - can someone explain why the PH is used rather than the elevation? The actual number of feet from MSL to Echo is still 3480', so shouldn't the lapse rate be applied to this figure, not 3240'?
Sorry if I am being dim.
Sorry if I am being dim.