Ask The Pilot

knasty

Active Member
Joined
Mar 11, 2010
Posts
936
I was on a CX A330 up to HKG on Monday. On pushback the Captain announced one brake was not operational and therefore the gear would need to stay down for two minutes after takeoff. What is the purpose of this? I expected the landing roll to be longer than usual but I was wrong; does autobrake just adjust? Thanks in advance.
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
I was on a CX A330 up to HKG on Monday. On pushback the Captain announced one brake was not operational and therefore the gear would need to stay down for two minutes after takeoff. What is the purpose of this? I expected the landing roll to be longer than usual but I was wrong; does autobrake just adjust? Thanks in advance.

When you retract the landing gear, braking is automatically applied to stop the wheels from turning....you don't really want something rotating at the better part of 200 mph within the wheel bay. Having a brake locked out means that this retraction braking won't be available on the affected wheel(s), so the gear is left down for 2 minutes to let them wind down.

When landing, auto braking is applied to get a particular deceleration rate, so it reduces with application of reverse thrust, and will simply apply a bit more braking if one brake isn't working. There's nothing there for you to notice, as the roll will be the same as usual.

The only time anything would be different, is if absolute maximum braking were required (as in an abort). This will be factored into the take off (and landing) data, and could reduce the maximum weight available. Something else that may need to be considered is the gear down obstacle clearance as well as performance following the loss of an engine. In some places (for instance off RWY 07) in HKG, this could be quite limiting.
 
Last edited:

Captain Halliday

Established Member
Joined
Jun 1, 2014
Posts
3,379
Which is more efficient, turning in the air or on the ground?

Let me explain the question with SYD as an example. Let's also simplify by assuming wind is calm, all runways available and there's nil traffic.

If you're operating SYD-CNS are you better off with the long taxi to RWY34 to be headed in the right direction once airborne, or taking RWY16 with a short taxi, but having more track miles?

Which gives the shorter time gate to gate?
Would there be much difference?
Which is most fuel efficient?
 

albatross710

Established Member
Joined
May 15, 2004
Posts
3,437
With the summer's schedule of Antarctic scenic flights about to get underway, what are they like from a captain's perspective?

Are they a prized flight that pilots hope to get? How do pilots get the task?
Have you done one, a few, none? if yes, what was the experience like?
What are the special flight planning and preparation requirements?

Cheers

Alby
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
Which is more efficient, turning in the air or on the ground?

Let me explain the question with SYD as an example. Let's also simplify by assuming wind is calm, all runways available and there's nil traffic.

If you're operating SYD-CNS are you better off with the long taxi to RWY34 to be headed in the right direction once airborne, or taking RWY16 with a short taxi, but having more track miles?

Which gives the shorter time gate to gate?
Would there be much difference?
Which is most fuel efficient?

Interesting question.

First thought is that it would be quicker to just get airborne, but as you will generally have to fly some distance in the wrong direction before you can turn, it might prove to be a very close thing.

Fuel use on the ground is relatively trivial, but that extra few miles before you can turn would probably add up to 3-5 minutes longer flight time, and that would exceed anything used in taxiing.

It's probably a good thing the runway is chosen by wind direction (mostly). Otherwise I could see everyone wanting to use a different runway.
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
With the summer's schedule of Antarctic scenic flights about to get underway, what are they like from a captain's perspective?

Dunno. Never done one. There's a very restricted list of people who crew them (so you don't have to train everyone).

Are they a prized flight that pilots hope to get?

I don't know about prized. Most people are up for anything that's a bit different.

How do pilots get the task?

Like most of these operations, I expect it would be a phone call from the fleet manager asking if you're interested. You probably can't go unless you've been before, which would mean the first flight would be as an extra.

Have you done one, a few, none? if yes, what was the experience like?

No, I haven't done one. I think I'd rather do a ferry to Manila. The hotel pool is much nicer.

What are the special flight planning and preparation requirements?

Specifically, I can't say, but as they've been doing them for years I'd expect them to have an extensive rundown available for anyone new.
 

Awesom Andy

Established Member
Joined
Nov 24, 2010
Posts
3,542
There's a very restricted list of people who crew them (so you don't have to train everyone).
What type of additional training would be required for this type of operations (not necessarily this particular Antarctica flight). I would presume it to be very similar to a normal flight, with a different set of way points to follow but it shouldn't have too many differences apart from that?
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
What type of additional training would be required for this type of operations (not necessarily this particular Antarctica flight). I would presume it to be very similar to a normal flight, with a different set of way points to follow but it shouldn't have too many differences apart from that?

Different routes are generally neither here nor there. They mostly don't differ enough to require specific training. There have been some in the past (one over China comes to mind) that had very extensive and high 'escape' routes (for decompression) that would end with you arriving at some pretty out of the way airports.

I expect the antarctic flights would have procedural information (I think the US base at McMurdo does some loose form of control) as well as a lot of information on white out and the cause of the ANZ accident. But of course....I haven't done it, so I can't say.
 
Joined
Oct 13, 2013
Posts
11,820
In this instance, you do know the length of the piece of string/thread.

You start with a known fuel figure, from which you subtract any needed reserves. What's left is 110% of the usable fuel. So, 10/11ths of that is the fuel you can burn (you need 10% variable). Divide that by the average fuel flow and you now have your endurance. Multiply that by the average TAS and you have the number of AIR MILES that you can fly. Multiply the average wind by the endurance and you get a way of converting the AIR MILES to GROUND miles.

Using the map scale, make your bit of string as long as the number of AIR MILES.

Attach one end of the string to where you are now.

Go to the destination, and plot it UPWIND by the distance you worked out for your AIR/GROUND conversion. Place the other end of the string there.

As long as you fly only two straight legs, you can fly to any point on the ellipse that the string will form when you stretch it out.

Clear as mud?

Does the curvature of the earth introduce a significant error?
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
Does the curvature of the earth introduce a significant error?

One of the biggest issues with charts is that they are a two dimensional representation of something that is 3d. The different forms of chart projection have differing positives and negatives from a navigation perspective.

Aircraft navigation (pre computer age anyway) generally uses Mercator and Lambert Conformal projections.
https://en.wikipedia.org/wiki/Mercator_projection
https://en.wikipedia.org/wiki/Lambert_conformal_conic_projection
https://en.wikipedia.org/wiki/List_of_map_projections

The Mercator has the positive that lines on it a of a constant track (aka rhumb lines), whereas straight lines on a Lambert are actually great circles, but have varying tracks. Within a small area the maps can be projected so that distortion is minimal. But, Greenland and the Antarctic are the classic examples of distortion, as they are shown (on virtually every map you'll ever look at) as being much larger than they really are.

The upshot is that distortion caused by the inability to accurately allow for the curvature of the earth is a constant issue. In the sort of problem we were looking at, it is minimal, and would not be worth worrying about.

It's another subject that would need to be looked at by those doing the polar flights too.
 
Last edited:
Sponsored Post

This is an example of a Sponsored Post, one of the many ways you can advertise on the Australian Frequent Flyer.

Other options include banner advertisements on our content and forum pages or our newsletter. You can also purchase an audio message on our podcast - or if you just want to try it out, you can sponsor a thread.

If you'd prefer not to see any advertisements (including these sponsored posts), you can become an AFF Supporter from just $6 and instantly remove all advertisements from our website!

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
Jb747,

where would be the average COG on a A380 from Australia at takeoff and then landing. Can you estimate it to a particular row(s) in the main cabin

CofG is described as a percentage of mean aerodynamic chord. At take off it's almost always exactly at 39.5%. In the cruise it's initially allowed to drift aft to 42%, and is then maintained between 40-42% by transferring fuel out of the tail. By the time you land, all of the tail fuel is gone, and fuel generally only remains in the feed tanks, so the CofG will have come forward to around 34%.

As to what seats it equates to, I have no idea, but it has to be forward of the main gear...
 

erkpod

Established Member
Joined
Jun 8, 2013
Posts
2,081
Reliable in what sense? They are never as reliable as trains (though I really don't know how reliable trains are, but they don't fall out of the sky). I suspect people have unrealistic expectations, fed from all sorts of sources. I remain amazed that aircraft quite reliably defeat gravity. Anything beyond that is good luck.


How mechanically reliable trains are in my experience depends who you talk to. While pilots stay on the one type, your average metro train driver is likely to drive every train type in the fleet. In my case, that's anything from mid/late 70s to now.

Mostly minor things are the ones that cause the smaller delays and many of them are caused by people (vandalism, medical emergencies etc).

Some of the larger issues come & people have trouble remembering procedures due to the low frequency of the issue, training, no checklists (I love the idea of checklists on planes!) & different procedures for different types.

Most drivers have preferences for trains they like & hate in dry conditions & also in wet conditions. Sometimes a train they like in the dry isn't the best in the wet - especially when the rain first starts or is very light.

Sometimes the same train can power, brake or feel different at either end even though it is the same train.
 
Joined
Oct 13, 2013
Posts
11,820
As to what seats it equates to, I have no idea, but it has to be forward of the main gear...

A friend wanted to know where the best Y seat/row is from a motion sickness pov.

Is it true that sitting around COG minimises pitch roll yaw and therefore motion sickness?

Also which chord: chord at the root of the wing?
 
Last edited:

day-heg

Member
Joined
May 17, 2011
Posts
262
Back in September, I passed an airline assessment and I started an A320 type rating last week. Come January I’ll be flying for a big European carrier whose aircraft are painted orange & white…

The TR is split into 2 parts; first up is 13 days of ground school covering technical aspects of the aircraft in preparation for a couple of exams, and 2 hours a day in a ‘virtual flight deck’ (essentially 6 or so touch screens linked up to a PC that display all of the important bits of the 320 coughpit) to run through SOPs, scans and flows, memory items etc that need to be actioned before, during and after a flight.

After that, we’re into the sim for 13 four hour sessions, each of which is split into pilot flying and pilot monitoring duties, and which culminates with the LST - the licence skills test. Normally I'd have been paired with another trainee, which means swapping seats half way through (to always be PF from the right hand seat) but I’m fortunate enough to have been paired with a Captain who is joining from another airline.

It’s a great result - no doubt I’ll be able to learn a huge amount from him, compared with being teamed up with another trainee. He has about 15,000hrs experience and been a Captain for 15 years; he's flown 757, 767, 747-200 and -400 Freighter (his most recent type) and also commanded an A320 for four years back in the 2000s, but ratings expire after three years, hence he is on the course. And the added bonus of doing all the sims in right hand seat… helps with muscle memory!

Week one covered flight instruments & control systems, power plants, hydraulics among other bits and was pretty full on, as no doubt this week will be! I will try to post a few more updates as I get into the sim phase at the end of November.
 

por930

Member
Joined
Oct 22, 2013
Posts
265
Week one covered flight instruments & control systems, power plants, hydraulics among other bits and was pretty full on, as no doubt this week will be! I will try to post a few more updates as I get into the sim phase at the end of November.

Hi day-heg, Hope you return as often as you can, as very interesting. Great that you have been paired with an x captain, who by the sounds of it will have crew management skills, as well as practiced pilot skills. Interesting he is returning to the 'dark side' away from Boeing.
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
Back in September, I passed an airline assessment and I started an A320 type rating last week. Come January I’ll be flying for a big European carrier whose aircraft are painted orange & white…

The TR is split into 2 parts; first up is 13 days of ground school covering technical aspects of the aircraft in preparation for a couple of exams, and 2 hours a day in a ‘virtual flight deck’ (essentially 6 or so touch screens linked up to a PC that display all of the important bits of the 320 coughpit) to run through SOPs, scans and flows, memory items etc that need to be actioned before, during and after a flight.

After that, we’re into the sim for 13 four hour sessions, each of which is split into pilot flying and pilot monitoring duties, and which culminates with the LST - the licence skills test. Normally I'd have been paired with another trainee, which means swapping seats half way through (to always be PF from the right hand seat) but I’m fortunate enough to have been paired with a Captain who is joining from another airline.

It’s a great result - no doubt I’ll be able to learn a huge amount from him, compared with being teamed up with another trainee. He has about 15,000hrs experience and been a Captain for 15 years; he's flown 757, 767, 747-200 and -400 Freighter (his most recent type) and also commanded an A320 for four years back in the 2000s, but ratings expire after three years, hence he is on the course. And the added bonus of doing all the sims in right hand seat… helps with muscle memory!

Week one covered flight instruments & control systems, power plants, hydraulics among other bits and was pretty full on, as no doubt this week will be! I will try to post a few more updates as I get into the sim phase at the end of November.

I think your previous training was in a 737 sim, so it will be interesting to hear what you think of the 320.

Having two people of the same rank training together is always pretty negative. Basically you wouldn't have the normal management flows that exist in a coughpit, so, you probably are better off doing the training with the Captain...especially as he's flown the 320 before.
 

jb747

Enthusiast
Joined
Mar 9, 2010
Posts
11,347
Sim time again. Two exercises on consecutive days, which is good for getting practice, but a bit harder to prepare for.


First exercise:


Starts with lots of low vis take offs and landings. The takeoffs will give you an abort at some stage, an engine failure and continue, and a normal take off. With the visibility down at 125 metres, hanging on the the centreline lights (which you can barely see) is immensely important given the swing that you get with an engine failure, whether you’re in a position to continue, or have to stop.


At the other end, landing, the first approach results in a go around after an engine failure at about 1,200 feet. The go around in LA is interesting as it involves a relatively low level, level off, and can actually require you to continue descending. Toss in a failed engine, and it requires a bit of thought. Later another approach with all engines, and you’ll get a landing, and another go around. This time the visibility is 200 metres, with the cloud base basically at the ground. You enter the flare without seeing anything of the runway…


The low vis procedures are only done once, as they are role specific. The Captain must always be the pilot flying, and the FO supporting.


Next the weather improves a bit, and we both fly an RNAV approach…a GPS based approach. If I recall correctly, both of these were preceded by an engine failure on take off, so they were flown one engine out. Landed off both.


Coffee break.


Now jump into the cruise on a flight from LAX to SYD.


A rapid temperature increase is loaded into the sim, which has the effect of placing the aircraft above maximum altitude. Then a very rapid and large tailwind is added, and the aircraft simply runs out of power and starts to decelerate, so basically you end up with a high altitude stall to recover from. Select -5º, let it gain some speed and lose a couple of thousand feet, and it flies away quite happily.


Approaching Hawaii (the big island) we get a message to the effect that there has been a major volcanic eruption. A quick look at our position shows that we are about 20 miles downwind of the event.


Turn away immediately, and as you start the checklist for a volcanic ash encounter you start getting all sorts of messages. Smoke alarms, cargo fire detections. The checklist has you increasing the bleed load on the engine (engine and wing anti ice on) as well as turning away, turning some of the internal air flows off…and most importantly minimum power. That means idle….you make no attempt to stay at your altitude. Next the engines start playing up, and soon you have multiple stall messages. The aircraft will drop to either alternate or direct law, depending upon how many engines are still operating. And then for fun, the ash starts to upset the air data. Initially two of the three air data computers are displaying rubbish. The FO is working full time trying to sort out the faults and get some power, and in the left seat you’re just trying to keep it under control, and headed in a reasonable direction.


In our case we managed to get two engines back, but as we tried to level off, the remaining air data was lost and we ended up with no airspeed displays at all. Sort that out, and end up level at about 18,000 feet. At this point we can look at getting the other engines back. In the ash scenario (as opposed to icing) the air data will never come back, but you can fly and land without great difficulty. Just need to take your time.


Pretty much the end of that sim…so off to a hotel for the night.


First thing next morning….


Jump to Dubai, where you take off for a little local training. Lose the auto thrust, and autopilots won’t engage. Fly manually back for an ILS. Do this exercise for both pilots.


LOFT exercise. You’re being vectored onto the ILS for 30L at Dubai, having just flown (two pilot) from London. 30R is closed. Weather is dusty, but nothing outlandish. Preceding aircraft has a landing event, and ends up blocking the runway. Go around and head out to the hold. Try to get an idea of the delay…request diversion to Dubai World (do it early to try to be ahead of the rush). Waited 5 seconds too long….Dubai World full. Decide to go to Muscat. TCAS RA during climb. “Company” tries to talk us into going to Al Ain (which would be a perfectly acceptable airport) but I didn’t want to make multiple changes. Various calls from ‘cabin’, etc, designed to either make you change your mind, or just to upset the flow. Ignore all.


Fly approach at Muscat. Get another TCAS warning, go around. Vectors to ILS and land.


Jump to Honolulu. This time we’re going to fly the LDA approach to 26L. We’ll do it twice each, with a cloud base of about 1,500 feet the first time, and the next time with all the numbers at the minima. The LDA is a bit like the old HK airport approach, as it has a 50 degree turn at low level to line up with the runway. The aircraft automatics can’t generate a synthetic FLS approach for this type of approach, so it’s flown in a mixture of modes. Basically with the higher cloud base it’s a doddle for both of us, but quite a handful when the vis is really reduced. Nevertheless we manage 4 landings..though some might have loosened the fillings.

 

moa999

Enthusiast
Joined
Jun 23, 2003
Posts
12,048
Interesting that both days involved scenarios going into HNL given this isn't exactly a common A380 airport.

Is this just to mix things up or as a result of it being a diversion for LAX/DFW
 
Top