Ask The Pilot

[eric2011]

I do remind myself in the USA though, that I'll be seeing feet and not metres in the distance countdown.

In the aviation world is there an excepted unit of measurement, i.e. is it meters or feet, miles or kilometres and does it differ for various activities i.e. fly at 38000 feet but the runway is 3400 meters long etc. Also is the english language used primarily throughout the world

 

[ChrisGibbs]

From memory under IFR flying a magnetic course (track) of 0 degrees through 179 degrees you flight plan at odd thousand foot MSL altitude and a magnetic course of 180 degrees through 359 degrees you flight plan at even thousand foot MSL altitude. On a bunch of recent SYD-HKG sectors the aircraft (B744) steps climbs from an initial FL340 through to FL380. However I've noticed during the final 120 minutes or the flights up over the Philippines across the South China sea into Hong Kong the flight has either climbed or descended off the standard "evens" flight level to take up an "odds" flight level (FL370 or FL390). I understand this could come about from a variety of reasons including traffic, weather, etc however are non standard flight levels allowed under RVSM? Is their any special clearance that is needed for this? How do you get around conflicting traffic on the same flight lane coming the other way - does ATC provide a clearance to operate within a specific altitude range?

A related question - if you are flying a magnetic track that is say 359 degrees and your magnetic track takes you 1 degree to the right does require you to change flight levels by 1,000ft to confirm to odds / evens flight levels or can you simply plan a non standard FL for the duration?

Thanks in advance.

 

[Stevo.1702]

In the aviation world is there an excepted unit of measurement, i.e. is it meters or feet, miles or kilometres and does it differ for various activities i.e. fly at 38000 feet but the runway is 3400 meters long etc. Also is the english language used primarily throughout the world

Why does Airservices Australia produce aerodrome charts with runway length and width only in meters and then upon landing you have 'x' thousand feet to run markers?

 

[jb747]

Why does Airservices Australia produce aerodrome charts with runway length and width only in meters and then upon landing you have 'x' thousand feet to run markers?

Do they? I haven't seen distance to run markers at any runway since I left the military.

On the other hand, and this applies to discussion about altitudes, 1,000 feet is a nice round number, and is much easier to visualise than 300 metres...even if they're the same thing.

BTW, good avatar.

 

[jb747]

In the aviation world is there an excepted unit of measurement, i.e. is it meters or feet, miles or kilometres and does it differ for various activities i.e. fly at 38000 feet but the runway is 3400 meters long etc. Also is the english language used primarily throughout the world

There are multiple standards, and if you fly internationally, you have to deal with all of them. The USA is supposedly a metric country, but not really. Visibility is quoted in hundreds of feet or as statute miles. Metres, knots, inches of mercury, and hectopascals are all mixed in there somewhere.

Vertically, thousands of feet provide a convenient measurement with nice round divisions. Some places do use metric altitudes (China and Russia), and it isn't as convenient as feet. Knots are nautical miles/hour, and have a basis in the shape of the earth and the divisions of latitude.

 

[jb747]

From memory under IFR flying a magnetic course (track) of 0 degrees through 179 degrees you flight plan at odd thousand foot MSL altitude and a magnetic course of 180 degrees through 359 degrees you flight plan at even thousand foot MSL altitude. On a bunch of recent SYD-HKG sectors the aircraft (B744) steps climbs from an initial FL340 through to FL380. However I've noticed during the final 120 minutes or the flights up over the Philippines across the South China sea into Hong Kong the flight has either climbed or descended off the standard "evens" flight level to take up an "odds" flight level (FL370 or FL390). I understand this could come about from a variety of reasons including traffic, weather, etc however are non standard flight levels allowed under RVSM? Is their any special clearance that is needed for this? How do you get around conflicting traffic on the same flight lane coming the other way - does ATC provide a clearance to operate within a specific altitude range?

A related question - if you are flying a magnetic track that is say 359 degrees and your magnetic track takes you 1 degree to the right does require you to change flight levels by 1,000ft to confirm to odds / evens flight levels or can you simply plan a non standard FL for the duration?

Firstly, not all airspace or routes is RVSM.

Whilst airlines will file a plan with the correct altitudes, it's up to ATC to assign those levels to an aircraft. Often, especially for short legs, it simply isn't worth doing so, and the aircraft will be left at the 'incorrect' level. Remember that any change could involve coordination with multiple other aircraft, and moving one could force others to non RVSM levels.

The 'incorrect' level will often be assigned to alleviate traffic issues (and this can occur at any time). In some parts of the world, the traffic flows tend to be directional at varying times of the day, and in those cases ATC will make use of the otherwise unused levels.

 

[RooFlyer]

I've been driving the highway that runs to the north end of the Hobart runway a fair bit over the past few days, and last Thursday or Friday a line of 'witches hats' type and other movable obstacles was placed across the width of the north end of the runway, maybe 50-100m in from the end; they appear to be there permanently, and not (say) to alert in-coming planes to some other, temporary obstacle or maybe people on the runway. I would think that they relate to proposed works to extend the runway and I guess are 'forcing' take-offs and landings away from the end of the runway to give better clearance of workers and vehicles.

I'm supposing there is still plenty of runway without that last bit for the planes that use it, but I wonder whether it is common to have such obstacles on and across the end of an active runway? Sucking some of those things into the engines if a take-off runs long would not be a good result (that said, if the plane isn't off the ground by that time, the witches hats would be the least of their worries!) .

These pics don't show the situation well, but hopefully an idea; its the silver-red looking things and they are set much further back from the end of the runway than the pictures indicate.

 

[anat0l]

I'm about to become a high school mathematics teacher. One of the main things that will be a focus of mine when teaching is how maths is used in the real world.

Do pilots need to be good at maths in order to be successful? I don't just mean being able to solve any of the basic times tables in your head in 2 seconds...

Now there's an "obviously" answer here as tertiary studies heading towards becoming a pilot include engineering and necessarily maths (including calculus and advanced algebra), but in a day to day setting after all the studies are over, are those advanced maths still important?

Some would say that computers (and computerised processes and procedures) have replaced so much of the manual effort that you don't really need to be good at maths to be a good pilot.

 

[jb747]

I've been driving the highway that runs to the north end of the Hobart runway a fair bit over the past few days, and last Thursday or Friday a line of 'witches hats' type and other movable obstacles was placed across the width of the north end of the runway, maybe 50-100m in from the end; they appear to be there permanently, and not (say) to alert in-coming planes to some other, temporary obstacle or maybe people on the runway. I would think that they relate to proposed works to extend the runway and I guess are 'forcing' take-offs and landings away from the end of the runway to give better clearance of workers and vehicles.

I'm supposing there is still plenty of runway without that last bit for the planes that use it, but I wonder whether it is common to have such obstacles on and across the end of an active runway? Sucking some of those things into the engines if a take-off runs long would not be a good result (that said, if the plane isn't off the ground by that time, the witches hats would be the least of their worries!) .

These pics don't show the situation well, but hopefully an idea; its the silver-red looking things and they are set much further back from the end of the runway than the pictures indicate.

Airfield cone markers....all you ever wanted to know about them is here: http://www.systemsinterface.com/linkservid/9B800E65-F737-460C-B26B7C17823BEC5F/showMeta/0/

They're attached to the ground, so they aren't likely to go anywhere. If you've done your performance calculations correctly, they're unlikely to be sucked into an engine. And if you're still on the ground at the point you reach the cones, you've got bigger problems.

 

[knasty]

I just got off an Erj 145 and noticed that the flaps and spoliers seem to have a much smaller extension that the heavies, and also seem to be smaller laterally than the heavies. Is my perception correct that the control surfaces are proportionally larger on the heavies tham smaller jets?

 

[jb747]

I'm about to become a high school mathematics teacher. One of the main things that will be a focus of mine when teaching is how maths is used in the real world.

Do pilots need to be good at maths in order to be successful? I don't just mean being able to solve any of the basic times tables in your head in 2 seconds...

Now there's an "obviously" answer here as tertiary studies heading towards becoming a pilot include engineering and necessarily maths (including calculus and advanced algebra), but in a day to day setting after all the studies are over, are those advanced maths still important?

Some would say that computers (and computerised processes and procedures) have replaced so much of the manual effort that you don't really need to be good at maths to be a good pilot.

The honest answer is probably not. Day to day, you use little more than basic algebra. The maths (and engineering/science) issues arise with regard to understanding the basics of what is going on around you. Computer systems are wonderful, until you find yourself in the middle of nowhere looking at black screens. The ability to work out the point of safe diversion to an off track location, allowing for wind, and using only a piece of string and a pencil is a skill that is pretty much lost. But, understanding why the string solution works is basic navigation...and that is also going.

Nowdays, I'd not be surprised if the more detailed maths requirements exist solely as filters. If you can't understand the maths, you're not that likely to understand the 'why' of aviation.

 

[jb747]

I just got off an Erj 145 and noticed that the flaps and spoliers seem to have a much smaller extension that the heavies, and also seem to be smaller laterally than the heavies. Is my perception correct that the control surfaces are proportionally larger on the heavies tham smaller jets?

Spoilers are the surfaces on the top of the wing. On the heavies they are broken up into many individual panels, though on small aircraft they might be as little as a single panel. So, that gives both complexity, and redundancy. Spoilers may be used for roll control, as speed brakes and as ground spoilers. In all cases, the amount of extension and the actual panels that move will vary according to need. The speed brake function also allows for direct pilot control of the amount of deflection.

On most aircraft, the ailerons are the outer panels of the wing only. They may additionally have a droop function which has the effect of partially incorporating them into the flaps. The 747 has an additional small aileron panel at about half span. At higher speeds the outer ailerons are inhibited and only the inners used, to reduce wing bending loads.

The effectiveness of the ailerons will be a function of speed, deflection and moment arm. So, I expect that for a shorter wing span, an aileron would need to be proportionally larger to be able to generate the same rolling moment. Looking at a plan view of the 145 (https://upload.wikimedia.org/wikipedia/commons/6/61/Bmi_erj145_planform_arp.jpg) the trailing edge of the wing is quite standard in that all of it is used for flaps and ailerons.

Here's a link to all you could ever want to know about the 145s control system. Plane Embraer EMBRAER-135-145

The larger aircraft have the space, complexity, and power systems to allow for much more complex flap systems. From a quick look at the ERJ's system, it looks as if the flaps are simple hinged panels, which extend to about 45º. In contrast the bigger aircraft will have area increasing flap systems, in which the panels extend aft in the initial stages of their motion to increase the total wing area, before bending down in the later stages. In the end it all comes down to a balance between need, cost, and complexity.

The wing itself will attempt to counter any roll inputs. The down-going wing has a slightly greater angle of attack, which will make more lift. The up going has the opposite effect. Roll rates in airliners probably top out at about 15-20º per second. Aircraft like the Mirage and A4 had sustained rates of 720º per second.

 

[RooFlyer]

Airfield cone markers....all you ever wanted to know about them is here: http://www.systemsinterface.com/linkservid/9B800E65-F737-460C-B26B7C17823BEC5F/showMeta/0/
<snip>.

Thanks again; and another topic for coughtail party chit-chat .

 

[Quickstatus]

SYD-PVG routing:

overflies MNL then heading to the Chinese coast west of Taiwan east of HKG before following the coastline to PVG. It seems to avoid the island of Taiwan.

Is there a reason this?

 

[por930]

The honest answer is probably not. Day to day, you use little more than basic algebra. The maths (and engineering/science) issues arise with regard to understanding the basics of what is going on around you. Computer systems are wonderful, until you find yourself in the middle of nowhere looking at black screens. The ability to work out the point of safe diversion to an off track location, allowing for wind, and using only a piece of string and a pencil is a skill that is pretty much lost. But, understanding why the string solution works is basic navigation...and that is also going.

Nowdays, I'd not be surprised if the more detailed maths requirements exist solely as filters. If you can't understand the maths, you're not that likely to understand the 'why' of aviation.

Looking on the pprune forum at the recent round of QF pilot applications, it seems that the better at mathematics you are, the less chance of being selected. Applicants who got all or most of the mathematics questions right (and apparently, being an online exam, the question would re-ask a question depending on how you answered. If you kept getting the question correct(you had X seconds per answer), then those applicants said they were advised, "maybe a career as a mathematics or science teacher would be a better vocation where you can use your advanced mathematics skills", and were passed over. Applicants who said they did, 'ok' at the mathematics questions, and those that answered in a way that Qantas thought ok, got through to the next stage.

 

[jb747]

SYD-PVG routing:

overflies MNL then heading to the Chinese coast west of Taiwan east of HKG before following the coastline to PVG. It seems to avoid the island of Taiwan.

Is there a reason this?

I haven't been up to that part of the world for quite a while, but I suspect that there is no coordination between ATC in China and Taiwan...you can't go from one to the other directly.

 

[jb747]

Looking on the pprune forum at the recent round of QF pilot applications, it seems that the better at mathematics you are, the less chance of being selected. Applicants who got all or most of the mathematics questions right (and apparently, being an online exam, the question would re-ask a question depending on how you answered. If you kept getting the question correct(you had X seconds per answer), then those applicants said they were advised, "maybe a career as a mathematics or science teacher would be a better vocation where you can use your advanced mathematics skills", and were passed over. Applicants who said they did, 'ok' at the mathematics questions, and those that answered in a way that Qantas thought ok, got through to the next stage.

I expect they say much the same with regard to piloting skills. Apparently old school pilots fit badly into the modern HR world. Who would you prefer when poo happens?

 

[anat0l]

Looking on the pprune forum at the recent round of QF pilot applications, it seems that the better at mathematics you are, the less chance of being selected. Applicants who got all or most of the mathematics questions right (and apparently, being an online exam, the question would re-ask a question depending on how you answered. If you kept getting the question correct(you had X seconds per answer), then those applicants said they were advised, "maybe a career as a mathematics or science teacher would be a better vocation where you can use your advanced mathematics skills", and were passed over. Applicants who said they did, 'ok' at the mathematics questions, and those that answered in a way that Qantas thought ok, got through to the next stage.

I wish I could say that being a good mathematics teacher doesn't require super nerdy mathematics guru skills, and a lot more of actually knowing how to teach mathematics (something that not every mathematically competent person can do without training and/or experience).

Curious observation; would be interesting to know the rationale (apart from the simplistic "advice" they were given). Only thing I could think of was that maybe the pundits who set the test thought that those who happened to answer "too fast" might have been robots and may have been filtering out those who have tried to fudge or cheat this part of the process in order to slip through.

Whilst I note jb747's observation of not needing more than basic algebra each day to function, in some ways do keep in mind that there are plenty of "average people on the street" who can't even do basic algebra. I would have thought a healthy competence in mental calculation and estimation would be useful, i.e. not because a computer can't do it, but because it helps you check for unusual calculations, e.g. did I slip a finger and enter the wrong number, or "that number seems unusually low/high".

Although it was also (or more so) a function of scientific knowledge and other experience factors, when QF32 was attempting to land and they were fiddling with numbers in the computer to find a landing scenario that could work, I imagine you need some mathematics sense to be able to know what could be tweaked or what kinds of limits could affect this and so on (not being a pilot or similar myself, this is somewhat based on my reading of RdC's book).

I'm not entirely sure if someone who is good at mathematics would necessarily be one who is a better thinker methodically or procedurally, or someone who can think properly under pressure. Those qualities are very important in good pilots, especially when things go wrong (and let's not entertain the idea that things often don't go wrong). I'd like to think that a good pilot knows and appreciates what all those numbers in the coughpit mean and doesn't necessarily fly solely "by the seat of their pants" or "by feel" (this isn't exactly like cooking without a recipe).

 

[Boca68]

I expect they say much the same with regard to piloting skills. Apparently old school pilots fit badly into the modern HR world. Who would you prefer when poo happens?

Errr, to be honest, a plumber or in serious cases, Imodium.

(hoping for the tradition of pilots having a dry sense of humour is still in play)





Anyway.....back on topic, the pprune forum is hardly definitive research.

 

[Hvr]

I haven't been up to that part of the world for quite a while, but I suspect that there is no coordination between ATC in China and Taiwan...you can't go from one to the other directly.

Actually you can, Hainan Airlines flies from TPE directly to PRC destinations such as PEK and CAN.