Ask The Pilot

[jb747]

JB - it's pretty common for planes to "clean up" as soon as possible after they become airborne; how much difference does this make in real terms to how the aircraft handles for you in the coughpit? Does it differ from one type to another?

The need to retract the gear promptly comes from the obstacle clearance, and also engine out climb requirements. Have a look at the engine out requirements, and discussion of the climb segments here: https://www.skybrary.aero/index.php..._Multi-Engine_Transport_Category_Jet_Aircraft

 

[jb747]

Ah, half of my previous post disappeared into the NBN somewhere...

During clean up, the first action is the opening of the gear doors. That increases the drag, so you need to lower the nose slightly (about a degree in the 380) to hold the speed. In the 767, sometimes the gear retraction wasn't quite symmetrical, and you could feel the yaw that induced.

The control forces vary a bit during any configuration change...it's just part of flying to hold the target attitudes whilst that is happening. The FBW aircraft do mask most changes though..you feel them much more in aircraft like the 747 or 767.

 

[Flyerqf]

All of us like Singapore, and nobody will lament the loss of Dubai.



The hotel in Dubai was particularly nice...so nice that there was no need to ever leave it.



I have no idea how they will build the patterns. One issue with the 380 for quite a while has been the lack of short patterns to help even up the lines of flying, and also for items like route checks or training. They may build patterns to London for both Sydney and Melbourne based crews...that would make sense, but we won't know until the patterns are built.

Personally, I hope the Melbourne crews get some Londons.

If the Melbourne crews don't get London flights, wouldn't there be too many melbourne based crew and no enough Sydney based, assuming the A380 goes back onto sydney to Hong Kong?

 

[jb747]

If the Melbourne crews don't get London flights, wouldn't there be too many melbourne based crew and no enough Sydney based, assuming the A380 goes back onto sydney to Hong Kong?

The Melbourne based pilots never did all of the flights from Melbourne anyway. I think they needed about 35 Captains to cover the full needs, and only ever got 22 or so, which meant that pilots have always come down from Sydney for many of the flights. If all that's left are LAs and Singapore, then they may move some of the positions back to Sydney. Most of the pilots commute from there, whether based in Melbourne or not.

 

[flychrisfly]

Most certainly. It is a very real issue on the 380, with 90 minute turnarounds. In Dubai, it's hot, you often land slightly downwind, and you always need K8 or K9. The brakes there are always cooled by the ground engineers with conditioned air. They often hit 500ºC, and sometimes appreciably more. In Melbourne they don't have any means of cooling the brakes, so if you heat them too much, it will delay the next departure. We will consider what the aircraft is doing next when deciding on how much braking, whether to do it manually or automatically, how much reverse, and which taxiway.

Do hot brakes prevent the engineers from, say, changing a tyre?

Separately, but related, do pilots always know when a tyre has blown?

 

[jb747]

Do hot brakes prevent the engineers from, say, changing a tyre?

We occasionally see the brakes approaching 700ºC, and they regularly hit 500ºC. You can't get near them, much less work on them. Even with virtually no braking on this morning's landing, we still had them at 350ºC. If you need to do work, they'll have to cool (be cooled) first.

Separately, but related, do pilots always know when a tyre has blown?

I don't recall ever blowing one. There's tyre pressure indications for every wheel, so the system would tell us if one deflated. If it has thrown some of the thread, you'd expect to feel the imbalance...and if it wasn't noticeable in the coughpit, then the crew sitting over it would be quick to ring.

 

[flychrisfly]

We occasionally see the brakes approaching 700ºC, and they regularly hit 500ºC. You can't get near them, much less work on them. Even with virtually no braking on this morning's landing, we still had them at 350ºC. If you need to do work, they'll have to cool (be cooled) first.


I don't recall ever blowing one. There's tyre pressure indications for every wheel, so the system would tell us if one deflated. If it has thrown some of the thread, you'd expect to feel the imbalance...and if it wasn't noticeable in the coughpit, then the crew sitting over it would be quick to ring.

Really?! As in:
1) Would you really feel it if just one out of 22 tyres popped? How would the feeling manifest itself in the coughpit?
2) The crew are really alert enough/trained to report this?

 

[jb747]

Really?!
1) Would you really feel it if just one out of 22 tyres popped? How would the feeling manifest itself in the coughpit?

They're very large, and rotating very fast. I'd expect the vibration caused by the imbalance to be noticeable to everyone on the aircraft, both crew and passengers. Beyond that, the warning system would report the loss of pressure to a tyre (if outside of the inhibit periods). It would be much more noticeable, and more of a problem, on take off rather than landing.

2) The crew are really alert enough/trained to report this?

You seem surprised. The crew regularly ring us if they notice something that they haven't seen before or consider unusual. And even if we think we know the answer, we always investigate further, as we don't want them to stop doing so, because they feel the pilots fob them off.

A blown tyre in the sim is very obvious, and the sims are normally pretty accurate...they have a lot of information to base their modelling on.

 

[flychrisfly]

You seem surprised. The crew regularly ring us if they notice something that they haven't seen before or consider unusual. And even if we think we know the answer, we always investigate further, as we don't want them to stop doing so, because they feel the pilots fob them off.

Yeah, I was. I was of the impression that there was limited interaction between cabin and tech crews. Not sure why but glad it's not the case.

Thanks, as always, for the responses.

 

[Quickstatus]

What level of mathematics, science and overall cognitive ability is necessary to be a good private pilot - say up to commercial license?

 

[jb747]

What level of mathematics, science and overall cognitive ability is necessary to be a good private pilot - say up to commercial license?

You'd really have to look at the CASA requirements to work out exactly what you need. As far as I know, being able to pass their subjects is sufficient.

I didn't go through the various stages of licensing, so I'm no expert on it. I had a restricted private licence, and I jumped from there to an ATPL...with the military covering the bits in the middle.

Off the top of my head though, at the private level, common sense will be the greatest asset you can have. The maths is pretty simple, basically being a bit of trig, and the ability to count to 60. Once you get to commercial though, you'll need to start understanding the 'why', so at that point the educational needs will increase.

A lot of what I was taught allows me to understand why things happen. I haven't been taught how to handle every situation under the sun, but the background allows me to work out my own solutions for most things. They generally don't have to be exact either...

Here's a question? You're going to a point that's exactly 500 miles due east of your current location. There's another place that's 100 miles north of the half way point on your track. So, if you were to fly to destination, and then directly to that diversion point, you'd fly a total of 500+269 = 769 miles.

You only have fuel to allow you to fly 600 miles. How far along track can you go before you have to divert?

Easy. Okay, now we'll put in a north easterly wind at 50 knots. Your TAS is 200 knots.

Work it out using a chart and a piece of thread.

 

[Quickstatus]

Need:

grid chart 1 big square = 100nm 1 little square = 10nm
length of string measured to 6 big squares

Mark on grid chart:
X = origin
A = starting point of string
B = planned destination
C = divert destination
D = point of diversion

a) No wind scenario (X=A)
If Length ADC is less than length of string then you can head to C
D can be anywhere on the chart or the point along AB that permits the length of the string to reach C from A

b) 50kt wind in direction of NE
As TAS is 200kts = 3 hours fuel for 600nm.
all you need to do is to translate point A away from X NE the equivalent of 5 small squares. This actually means by 4 small squares E and 3 small squares N for every hour. Therefore for the 3 hrs translate point A E by 12 small squares and N by 9 small squares
Point C remains in the same place.
D remains the point which allows the string to reach C

Envisage string is tied between 2 pins at A and C. String is now not taut. D is just the point along AB which makes the string taut.

There is an area on the chart where the string is taut . All airports within this area are therefore reachable with the amount of fuel

instead of grid chart just use a map with a scale
In a right angle triangle the lengths of the sides are always 3,4,5 with 5 being the hypotenuse.

 

[petercr]

Maybe that ancient Babylonian tablet that was found recently was actually an early attempt at a flight calculator
(had lots of ratios to make trig easier)

 

[jb747]

I can now just imagine everyone trying to decipher QS’s answer. But I don’t think that we need any maths more complex, and if you can see the theory behind the answer, then you know more than some of the FMC jockeys.

 

[Quickstatus]

Are you at that stage where you can do a reasonable estimate in your head rather than relying on string?

 

[jb747]

I've always been at that stage....I was a navigator before I became a pilot. And in the real world, these days, you have a look at roughly where it will be, put that in as a turning point in the FMC, and see what that does to your fuel....

 

[mjt57]

I can now just imagine everyone trying to decipher QS’s answer. .

Nope. He lost me after "Need:"....

 

[trooper]

In the Navy we had a device called a "Battenberg" for rapidly working out relative Velocity problems - like the one you proposed - but of course often more complex...
We COULD use plotting sheets ("map and string") but the Battenberg was theoretically quicker.....

Not for me..I liked its alternative name of Baffleberg...plotting sheets were my preference....

Did you have any such hand held aid at any stage in your flying?

 

[jb747]

In the Navy we had a device called a "Battenberg" for rapidly working out relative Velocity problems - like the one you proposed - but of course often more complex...
We COULD use plotting sheets ("map and string") but the Battenberg was theoretically quicker.....

Not for me..I liked its alternative name of Baffleberg...plotting sheets were my preference....

Did you have any such hand held aid at any stage in your flying?

The members of the Fleet Air Arm who eventually decided to go to sea to get a watch keeping ticket (which you needed at the time to become 'General List', and so have more potential promotions opened up to you) invariably described seamanship as just the same as airmanship...only at 10 knots.

The Observers all knew how to solve the various problems via plotting, but few aircraft actually had the facilities to allow you to do so. The Seaking had a ground referenced radar plot screen, so intercepts on that were easily plotted with a grease pen. The fighter pilot solution was simply to go faster and treat ships as stationary targets.

A similar tool to the Battenberg was the navigation computer that is still used to this day in many aviation applications. The E6B has been around for donkey's years, and allows all sort of calculations. I haven't carried one for 30 years, but you still see people who have the small version in their pocket. E6B - Wikipedia

 

[mikenz]

How long to various elements of an aircraft last?
Would the engines that are fitted to a new aircraft remain for the life of the aircraft? (acknowledging their maintenance throughout their life)
How often are wheels replaced?