The great big "ask an airline pilot" thread!

Tenger

View Profile wrote: »

However for moderate turbulence the AP is generally quite good at keeping speed/heading/altitude.

I think the poster who asked the question had an image of an inflight cruise control in mind when they pondered the aircraft diverging due to surface curvature.

pclancy

Having never flown anything bigger then a cessna I wonder how hard it is keep your large aircraft steady at 35,000 ft by hand. Are you just constantly adjusting the trim or actually hand flying it trying to stay at the altitude you want?

airbus125

Hi,
I;m 14 and have been interested in aviation since a very young age. I was just wondering is there any hope of me getting a job as an aer lingus pile when I'm older. They seem to be getting deliveries for airbus a350s in 2018 so will they be hiring them. This is kind of stupid but it is any use contacting them now and does anyone know what type of qualifications you need.
Thanks

CaptainSkidmark

i enjoyed turbulence for the first time ever today! i knew take off was going to be rough as i seen the flight before us all over the shop and i knew it was no problem to it, amazing how worse things seem from inside!

Tenger

CaptainSkidmark wrote: »

i enjoyed turbulence for the first time ever today!

Welcome to the world of professional flyers.....

....of course PiC's really hate crosswinds!!!

roundymac

airbus125 wrote: »

Hi,
I;m 14 and have been interested in aviation since a very young age. I was just wondering is there any hope of me getting a job as an aer lingus pile when I'm older. They seem to be getting deliveries for airbus a350s in 2018 so will they be hiring them. This is kind of stupid but it is any use contacting them now and does anyone know what type of qualifications you need.
Thanks

Beware, this is the OP for the thread Aer Lingus Pilot Job. A troll perhaps?

cyrusdvirus

roundymac wrote: »

Beware, this is the OP for the thread Aer Lingus Pilot Job. A troll perhaps?

Or it could just be a 14 yr old kid asking questions??

Bearcat

View Profile wrote: »

If the turbulence is severe enough the autopilot may disengage. The pilot will then take manual control until the turbulence has passed and he/she can re-engage the AP.
Sometimes in turbulence you may notice the AP struggling to keep the altitude or speed in which case you will intervene and take manual control.

However for moderate turbulence the AP is generally quite good at keeping speed/heading.

Airbus recommend in severe Turb that AP remains engage and the use of manual thrust at a designated N1 setting. Boeings especially earlier types had difficulty remaining engaged in primary levels of automation and often lapsed into basic modes of control wheel steering (cws) in SEV Turb.

amen

You'd need to be travelling at a few kilometres per second to have to worry about that.

No you wouldn't

I think the poster who asked the question had an image of an inflight cruise control in mind when they pondered the aircraft diverging due to surface curvature.

Why. The height is relative to the ground/sea. As such its not a straight line, as I think you are visualising it. It follows the curvature in general.

Well I know its following the earth's curvature but I wanted to know how the autopilot determine when/if a change we required to ensure the correct altitude was maintained by following the curvature.

Taking that that the earths curvature is roughly 0.2m per KM ie. if I start at point A and walk at a tangent to the earth then after walking 1000m I should be 0.2m above the surface of the earth.

So if the plane flies 5000KM (Transatlantic) starting at 10,000m then at the other end if should be at 11,000m allowing for level flight.

If my calculations are correct then at which stage does the autopilot correct the plane to ensure altitude is maintained at 10,0000m?

BostonB

amen wrote: »

...Well I know its following the earth's curvature but I wanted to know how the autopilot determine when/if a change we required to ensure the correct altitude was maintained by following the curvature....

Your question seems to be how often does the autopilot, refresh. Its only my guess, I'm not a pilot. I don't know. But I would assume continuously, as in many times a second. There's probably redundancy built in too.

BostonB

amen wrote: »

...
So if the plane flies 5000KM (Transatlantic) starting at 10,000m then at the other end if should be at 11,000m allowing for level flight...

I assume "Level flight" is actually a curve. Not level as in a straight line.

View Profile

... but I wanted to know how the autopilot determine when/if a change we required to ensure the correct altitude was maintained by following the curvature.

Not sure if im answering your question but the Autopilot is flying at a flight level which is dictated by the local atmospheric pressure not the earth's curvature.

CaptainSkidmark

Tenger wrote: »

Welcome to the world of professional flyers.....

....of course PiC's really hate crosswinds!!!

i wouldnt mind! but ive been flying a lot to and from work in AMS and FRA over the last 2 years so its not before time!

roundymac

gatecrash wrote: »

Or it could just be a 14 yr old kid asking questions??

Well, why did he start a thread, gets plenty of advice and then comes onto this thread with exactly the same question?

airbus125

roundymac wrote: »

Well, why did he start a thread, gets plenty of advice and then comes onto this thread with exactly the same question?

I just copied on pasted.

amen

Not sure if im answering your question but the Autopilot is flying at a flight level which is dictated by the local atmospheric pressure not the earth's curvature.

which I can accept but at some stage the autopilot has to adjust the plane to stay at a constant pressure so is it making constant adjustements?

If the above (local atmospheric pressure) is true then when what happens you fly into areas of higher/lower pressures ?

I think before modern jets pilots use to adjust altimeters based on local pressure readings at destination airports. Maybe the flight computer does the same?

tricky D

amen wrote: »

No you wouldn't

Well I know its following the earth's curvature but I wanted to know how the autopilot determine when/if a change we required to ensure the correct altitude was maintained by following the curvature.

Taking that that the earths curvature is roughly 0.2m per KM ie. if I start at point A and walk at a tangent to the earth then after walking 1000m I should be 0.2m above the surface of the earth.

So if the plane flies 5000KM (Transatlantic) starting at 10,000m then at the other end if should be at 11,000m allowing for level flight.

If my calculations are correct then at which stage does the autopilot correct the plane to ensure altitude is maintained at 10,0000m?

You are neglecting centripetal force which would, at the speeds we are concerned with, keep the flightpath at pretty much on the curvature. http://en.wikipedia.org/wiki/Centripetal_force Any deviation upwards is so small that the AP would absorb it easily in maintaining pressure, which isn't perfectly constant anyway, as per below.

amen wrote: »

which I can accept but at some stage the autopilot has to adjust the plane to stay at a constant pressure so is it making constant adjustements?

If the above (local atmospheric pressure) is true then when what happens you fly into areas of higher/lower pressures ?

I think before modern jets pilots use to adjust altimeters based on local pressure readings at destination airports. Maybe the flight computer does the same?

QNH is to calibrate for the altitude of the runway so you don't hit it too late or early. http://en.wikipedia.org/wiki/QNH

xflyer

While all very interesting and fun to work out. Practically speaking it doesn't arise. In fact once above the transition altitude aircraft fly at flight levels based on the standard pressure setting which is 1013.2. This altitude is the 'pressure altitude' and it's not a true indication of the aircraft's height above ground or sea level. This ensures that all aircraft operating in the flight levels will have the same setting on their altimeter.

Thus the autopilot or indeed pilot will maintain the selected flight level. The actual pressure is of only academic interest to the pilot until it's time to descend below the transition altitude near the destination.

Thus an aircraft will climb or descend relative to the ground as it passes through differing barometric pressures. For example flying from high pressure to low pressure will result in the altimeter showing an increase. This is corrected by descending. Fly into a high pressure zone and the altimeter shows a decrease. On a long flight an aircraft may climb or descend relative to sea level several times as it passes through varying barometric pressures. But the altimeter will continue to indicate the selected level.

So the curvature of the Earth hardly enters into it.

cyrusdvirus

roundymac wrote: »

Well, why did he start a thread, gets plenty of advice and then comes onto this thread with exactly the same question?

I dunno..maybe the great big ask an airline pilot thread name gave it away.
Cos, y'know, he's looking for answers on being an airline pilot???

Just cos someone posts the same statement/question in the same forum under 2 different threads doesn't make them a troll.

Breaking the forum rules, yes, troll no.

amen

xflyer thanks for your question and while I guess the plane ascends/descends several times I'm more interested in does the autopilot what until there is say a 1%/5%/10% variance or does it follow the change in order to stay at the correct altitude?

xflyer

I'm no expert on autopilots, perhaps an avionics Engineer might be better placed to explain the tolerances. As corrections will be applied several times a second it would largely be imperceptible to the pilot.

Particularly when you consider all the other factors at play. Even people and trolleys moving up and down the cabin will cause the aircraft to become slightly out of trim and cause a climb or descent which will be instantly corrected by the autopilot. Then there's the constantly moving atmosphere. Changes in pressure or the curvature of the Earth would only be a tiny part of the equation.

Even if you're hand flying, you may be moving the controls constantly to correct but there would be little or no visible indication on the altimeter although the VSI might be waving like a drowning man.

Lustrum

How did you get your first job?

This may be the prime concern of all aspiring pilots (once the cost of it has been taken care of) I suspect

paky

what kind of qualifications do you need to become a pilot? do you need a degree? i have a mate in the us airforce and his degree was in political science and wasnt even relevant to flying?

Tenger

paky wrote: »

what kind of qualifications do you need to become a pilot? do you need a degree? i have a mate in the us airforce and his degree was in political science and wasnt even relevant to flying?

You don't NEED a degree to be an airline pilot..........

........but having a degree shows you have the ability to learn and are at least above average intelligence.

Mental stability, mental compartmentalisation, analytical thinking, physical fitness, problem solving ability and overall mindset are more important than the degree.

boeingboy

Right place...right time Lustrum


I self sponsored i.e. paid for my Irish Cpl/Ir multi engine and the company/school I did it all with put me thru the training for their twin turbine aircraft which I flew basically until they shut shop so I headed west to US and the rest is history....my history. With the same carrier now 15 years this week.

Couple of DEC jobs coming up here so I will probably take one soon and stay in Ireland for good .

Regards to education. Noone ever asked me for any other qualifications except Licence etc etc

Priority Right

Lustrum wrote: »

How did you get your first job?

This may be the prime concern of all aspiring pilots (once the cost of it has been taken care of) I suspect

Was at a simulator centre in London waiting for a friend. A guy asked did I want a go. I did well and a few days later I got a phonecall asking did I want an interview. Then for second airline I rang a person in charge about something unrelated and he asked was I available the next morning. I was so I did an interview/sim and got accepted. All very random and through meeting people.

xflyer

paky wrote: »

what kind of qualifications do you need to become a pilot? do you need a degree? i have a mate in the us airforce and his degree was in political science and wasnt even relevant to flying?

Generally the US military require a four year college degree for their pilots. Except the army. Each military has it's own requirements, mostly just high school. The major airlines in the US usually required a college degree on top of at least 1500 hours and an ATPL before they'd even look at you.

But it's different in Europe where unless it's an organised sponsorship or cadet scheme. No one is interested in what you did at school. It's your pilot qualifications that they want.

Effectively the only qualification needed is money and lots of it.

As for my first flying job. I saw a posting on an internet forum. I sent an email. The phone rang and we had a chat. At the end of the conversation. I went to my wife slightly shocked. 'I've just got a job as a pilot' I told her. Simple as that. An overnight success after twenty years.

silverwood

Tenger wrote: »

You don't NEED a degree to be an airline pilot..........

........but having a degree shows you have the ability to learn and are at least above average intelligence.

Mental stability, mental compartmentalisation, analytical thinking, physical fitness, problem solving ability and overall mindset are more important than the degree.

You certainly do not need to be above average intelligence to successfully pass many degrees. I'm sure it helps in getting a better final grade but it is very achievable to pass whilst being of normal intelligence.

Tenger

Having a degree shows you are intelligent and have the ability to learn and apply yourself, both skills needed to earn your CPL.

silverwood

Yeah fair enough, my comment came across more serious than I intended