Ask The Pilot

[geordieladinoz]

Hi JB

Never felt the need to post but really enjoy being educated through this topic.

I'm currently in The Qantas lounge in T2 and flights are taking off and landing in an East - West direction (which is keeping me more entertained than watching Ellen on the TV). That is, all apart from QF11 (A380) and QF7 (B747) which took off towards the South. Why would it be that only those 2 flights in the half an hour or so will have used that runway?

I would have said it was due to them being 'Bigger Birds' but the Air Pacific B747 took off to the West and I have previously landed on an A380 in the Westerly direction so both types of plane are obviously capable of using that runway.

Was it down to Qantas jumping the queue?

Sorry for some of the simplistic terminology. I'm a keen flyer but not an avid enthusiast!

 

[markis10]

Hi JB

Never felt the need to post but really enjoy being educated through this topic.

I'm currently in The Qantas lounge in T2 and flights are taking off and landing in an East - West direction (which is keeping me more entertained than watching Ellen on the TV). That is, all apart from QF11 (A380) and QF7 (B747) which took off towards the South. Why would it be that only those 2 flights in the half an hour or so will have used that runway?

I would have said it was due to them being 'Bigger Birds' but the Air Pacific B747 took off to the West and I have previously landed on an A380 in the Westerly direction so both types of plane are obviously capable of using that runway.

Was it down to Qantas jumping the queue?

Sorry for some of the simplistic terminology. I'm a keen flyer but not an avid enthusiast!

Current ATIS:

TMP: 20. VIS: GT 10KM. CLD: FEW045. RWY 25. EXP TURB IN CIRCUIT AREA. WIND: 250/25. QNH: 1010.

I would suspect the runway is short for 11 and 7, given their extra weight, at a rough guess they 100T heavier on take off than Air Pacific and they prefer the longer runway.
An aircrafts take off and landing distances required vary based on their own weight and outside factors such as altitude and wind, landing distance is rarely longer than take off distance required!

 

[geordieladinoz]

Current ATIS:

TMP: 20. VIS: GT 10KM. CLD: FEW045. RWY 25. EXP TURB IN CIRCUIT AREA. WIND: 250/25. QNH: 1010.

I would suspect the runway is short for 11 and 7, given their extra weight, at a rough guess they 100T heavier on take off than Air Pacific and they prefer the longer runway.
An aircrafts take off and landing distances required vary based on their own weight and outside factors such as altitude and wind, landing distance is rarely longer than take off distance required!

Thanks markis10, makes sense.

My TMW flight has been delayed so also seen what appeared to be a VA1 take off heading to the South, I guess for the same fuel related reasons.

And another 15 minute delay sees UA840 head into the Southerly distance.

That's my education for the day!

 

[wafliron]

But, if you then join a queue, and the expected delay is beyond the legal fuel limits, then you declare an emergency. You don't have to be out of fuel...just with a projection that is below the requirements

I believe you've previously stated that you won't always be carrying sufficient fuel to make it to a diversion airport... so in that case, if visibility falls below minimum I assume you have no choice but to just go ahead with the landing anyway. How risky is that - landing with visibility below normal minimum?

 

[Industrial]

My main reason for actually joining this forum was this thread, I must firstly thank those who have contributed. It took me 4 days to get through it and it was like a good book, I couldn't put it down.

JB, I just went searching for your youtube channel today to find it gone.

it has been interesting watching the crew go through the checklists prior to take off, just wondering how many would be completed in a normal take off from boarding to clean up?

Thanks.

 

[jb747]

My main reason for actually joining this forum was this thread, I must firstly thank those who have contributed. It took me 4 days to get through it and it was like a good book, I couldn't put it down.

JB, I just went searching for your youtube channel today to find it gone.

it has been interesting watching the crew go through the checklists prior to take off, just wondering how many would be completed in a normal take off from boarding to clean up?

The attention that the youtube channel brought wasn't always positive. I've been wondering about its future for a while. It will probably reappear on Vimeo at some stage, but I think I'm done with youtube.

There are hundreds of items to be completed. Some are switch selections, others are procedures (i.e. the loading of the FMC), whilst others are things like briefing yourself on the ATC procedures you'll be following. The checklists are quite short, and cover very basic items. Many of the items are automatically checked, so a call for the "after take off checklist", will, in most cases, result in the PNF saying "after take off checklist complete", without calling any items at all, as they will already have been detected by the aircraft, and have turned green. In the 380 they are shown on the upper centre screen.

Checklists:
BEFORE START
AFTER START
BEFORE TAKE OFF
AFTER TAKE OFF
APPROACH
LANDING
AFTER LANDING
PARKING

 

[jb747]

I'm currently in The Qantas lounge in T2 and flights are taking off and landing in an East - West direction (which is keeping me more entertained than watching Ellen on the TV). That is, all apart from QF11 (A380) and QF7 (B747) which took off towards the South. Why would it be that only those 2 flights in the half an hour or so will have used that runway?

I would have said it was due to them being 'Bigger Birds' but the Air Pacific B747 took off to the West and I have previously landed on an A380 in the Westerly direction so both types of plane are obviously capable of using that runway.

All aircraft, even when the same type, are not equal. The two that you've mentioned are both going a long way, and will be close to maximum weight, whereas as flight to Fiji in a 747 is so short to be hardly worth pulling up the wheels. There would easily be over 100 tonnes difference in weight.

Looking at the A380...firstly ATC prefer to keep it away from the other aircraft, as its wake is substantial, and it requires longer than normal spacing between it and subsequent aircraft.

Using the weather conditions Markis provided, a 380 going off 25 would have needed TOGA power to get airborne with a maximum weight of 542 tonnes. Over on 16 the same aircraft could lift up to 610 tonnes (well above the max structural weight anyway), and could lift that same 542 tonnes with a very substantial derate (and it could go a max TOW and still be derated). Derating makes a big difference to how long the engines last. Take off crosswinds aren't anywhere near as hard to handle as landing crosswinds, so we'll almost always take a cross wind if it gives us a better derate...the upshot being that we'll almost always use a long runway in preference to a shorter one.

Was it down to Qantas jumping the queue?

We'd love to be able to jump the queue, but ATC quite rigidly control who goes, and when. Use of a single runway is extremely constraining for them.

 

[jb747]

I believe you've previously stated that you won't always be carrying sufficient fuel to make it to a diversion airport... so in that case, if visibility falls below minimum I assume you have no choice but to just go ahead with the landing anyway. How risky is that - landing with visibility below normal minimum?

Some places, like London, have multiple airports in close proximity that are capable of handling large aircraft. Others, like Sydney, aren't so lucky. The amount of fuel needed to handle a 500 mile diversion is rarely available, and will only be carried if the weather forecast requires it. Close in diversions can almost always be handled by the standard arrival fuel, but in most cases they are worthless as diversions as any nasty weather is just as likely to be affecting them as it is your actual destination.

During the flight you will have access to both updated forecasts, and also TTFs (trend type forecasts). TTFs are actually a combination of the airport's actual weather and a short term forecast (they generally have a 2 to 3 hour total validity). A TTF overrules a forecast. During the course of your flight you'll keep an eye on the destination weather, and a closer eye on places currently close to you. As you reach the end of the flight you'll be looking for a TTF that covers your arrival, and that will decide what fuel you need. If at your last diversion decision point the TTF requires something you don't have, then you divert, but if you can cover whatever it requires, then you continue.

If the weather (TTF) changes after the decision point then you have little to no choice, but, to continue. But, the weather will almost certainly still be well above the approach minima, as there are quite substantial buffers between the alternate criteria, and the actual minima. The two main 'gotchas' are fog and thunderstorms. Fog can appear from nowhere, with no mention on any forecast until, lo and behold, there it is on the ATIS. Thankfully that's rare. Fog is probably the least of the problems though, because most aircraft will be able to complete an autoland, as long as the airport is equipped with an ILS. Most ILS installations aren't rated to CAT II/III, but often the reasons are to do with the lighting or backup power, and not the ILS itself. So, in that instance, continuing to land is almost perfectly safe, though it does require some paperwork.

Thunderstorms are very different animals and there you might want to consider any other option other than landing. Time machines are good.

If the airport is not equipped with an ILS, or the ILS is not aligned with the runway, so an autoland is not an option, continuing below the minima is indeed a very dangerous thing to do. I think that was recently demonstrated at Bali.

To go below the minima, you MUST have declared an emergency.

 

[Major]

Is windshear on takeoff something that would affect the A380 or only the smaller aircraft ?

Report: Qantas B738 at Perth on Dec 4th 2012, windshear on takeoff run past V1

 

[jb747]

Is windshear on takeoff something that would affect the A380 or only the smaller aircraft ?

Report: Qantas B738 at Perth on Dec 4th 2012, windshear on takeoff run past V1

An interesting event. Perth can be quite a nasty place to operate to/from, for many reasons.

Windshear can affect any aircraft. Civil or military, large or small.

As this happened on the ground...the wind was 8 knots of headwind as they lined up, which means they'd have 131 knots of groundspeed at Vr (139-8). That represents the kinetic energy that the engines need to give the aircraft during the ground roll.

But, with the wind swinging to a 20 knot tail wind, the groundspeed at Vr would now need to be 159 knots....roughly 47% more energy required (remember, it's related to velocity squared).

Various armchair experts on Avweb were talking about aborting, but it needs to be recognised that although we base the abort decision on a speed, it is unsaid that that speed has to occur at a particular point on the runway. Something that slows the acceleration will move the point at which V1 is attained further along the runway, so it will soon become be too fast for a safe stop.

We use various methods of avoiding windshear issues, ranging from choosing different runways, delaying the take off, using different configurations, and of course using all of the power. Nothing in the prelims of this would have tripped the 'windshear' switch in any pilots mind....

I see this as having been very quickly recognised, and well handled.

 

[RooFlyer]

I expect this topic is a bit of an old chestnut, but would be grateful for your forbearance.

If there is a situation where you just have to get the bird on the ground ASAP, how do you manage the landing at the nearest acceptable airport? I'm mainly thinking of a long haul flight, say at 40,000 ft and yes, I'm thinking of the possibility of having to land in countries the likes of Iran, any of the 'stans, etc, or say most of the central African countries by way of example.

I'd be interested to know:

* Given your planned route, is there a pre-loaded list of emergency landing airports that you might access at any given point / a given scenario?

* If you are say, long haul at 40,000 ft, and need to land ASAP, which type of ATC do you contact and how? That of the country where you want to land into, or is there an international ATC you would contact covering the sector you are in and they liaise with the local ATC?

* Might there ever an issue of having to 'wake up' either an ATC or an airport? Or would you simply decide to vector to a known "open/acceptable" airport?

* Can you refer to any case where a passenger aircraft has had to land at a less-then-friendly airport, under circumstances which might be regarded as "I'm landing whether you like it or not" ?

 

[jb747]

If there is a situation where you just have to get the bird on the ground ASAP, how do you manage the landing at the nearest acceptable airport? I'm mainly thinking of a long haul flight, say at 40,000 ft and yes, I'm thinking of the possibility of having to land in countries the likes of Iran, any of the 'stans, etc, or say most of the central African countries by way of example.

You are always under the control of some ATC authority or other. Of course they may be very long way away (i.e. Melbourne looks after most of the Indian Ocean), but they're always a good starting point.

We carry charts for a large number of places that we could potentially have to use. They exist as paper (for the time being), on the coughpit laptops, and on our iPads.

ATC in the 'stans and Iran is perfectly acceptable, and I'd expect they'd be very helpful in an emergency. I'd have no problem landing in places like Ashgabat or Baku. I don't fly over Central Africa, but I expect you'd have a reasonable number of choices. There is an article about a US airliner landing in Iran on Flightpodcast.

* Given your planned route, is there a pre-loaded list of emergency landing airports that you might access at any given point / a given scenario?

Our FMCs constantly give us a listing of 'nearest' airports. Additionally, we load in up to four 'fixes' which are normally our enroute alternates (and change them as the trip progresses).

The system does offer three secondary routes, and some people load routings into them. Nothing is automatically pre loaded. I'm not keen on having too much loaded, and you really have no idea how any scenario will play out...but you can be sure that whatever happens will not be what you planned.

* If you are say, long haul at 40,000 ft, and need to land ASAP, which type of ATC do you contact and how? That of the country where you want to land into, or is there an international ATC you would contact covering the sector you are in and they liaise with the local ATC?

You're always talking to somebody. Most likely they'll handle you relatively normally, and simply hand you over to the appropriate 'approach' people. Some more isolated places may not have active towers, and there you'll remain with the enroute ATC on one radio, whilst using another for local frequency broadcasts (and to turn on the lights if they are radio activated).

* Might there ever an issue of having to 'wake up' either an ATC or an airport? Or would you simply decide to vector to a known "open/acceptable" airport?

The 380 is quite constrained in just which airports it can use, and virtually all of our choices are major airfields. Many Australian airports are never manned, and you just remotely turn on the lights, and sort out your own act.

* Can you refer to any case where a passenger aircraft has had to land at a less-then-friendly airport, under circumstances which might be regarded as "I'm landing whether you like it or not" ?

I'm sure it would be in wikipedia somewhere.

 

[RooFlyer]

Thanks again for the thorough answer!

 

[fairbasa]

Apologies if you've answered this already, but is there a set criteria for cancelling a flight based upon conditions at the destination?

I ask this just because I was pretty surprised when flights were still landing at PHE during the blue alert immediately prior to an imminent cyclone. I think the winds were gusting and approaching the 100km/h mark at the time. What are the maximum wind speeds you could safely land/take-off in?

 

[wafliron]

Thanks for the info JB, as always.

The two main 'gotchas' are fog and thunderstorms. Fog can appear from nowhere, with no mention on any forecast until, lo and behold, there it is on the ATIS. Thankfully that's rare. Fog is probably the least of the problems though, because most aircraft will be able to complete an autoland, as long as the airport is equipped with an ILS. Most ILS installations aren't rated to CAT II/III, but often the reasons are to do with the lighting or backup power, and not the ILS itself. So, in that instance, continuing to land is almost perfectly safe, though it does require some paperwork.

This is interesting (and good!) to know - that many ILS installations are technically capable of CAT II/III operation, but simply don't have the official rating due to relatively minor factors like lighting / backup power / etc. Given your below comments about the danger of landing below minima without CAT II/III ILS, and the lack of major incidents involving commercial airliners in Australia, I assume most major Australian airports would fall into this category - having ILS systems that are technically CAT II/III capable even though they don't carry the official rating (I believe MEL is the only one actually rated to CAT III)?

Thunderstorms are very different animals and there you might want to consider any other option other than landing. Time machines are good.

If the airport is not equipped with an ILS, or the ILS is not aligned with the runway, so an autoland is not an option, continuing below the minima is indeed a very dangerous thing to do. I think that was recently demonstrated at Bali.

How often do you run into this sort of situation - where you are faced with a thunderstorm, or low vis and no suitable ILS, and have no choice but to attempt the landing anyway? I guess you can either take that as a literal "you", or a wider "you" encompass the general population of commercial pilots. Whichever you think is more relevant / interesting

 

[Shorns]

JB, as said before, a very enjoyable read and your knowledge is most welcome!

When approaching a airport that you no longer have an alternative for (ie you're next to land) is it a concern for you that through something other than weather the runway became inoperable? The most obvious but of course unfortunate scenario would be some sort of incident on the runway with the aircraft ahead of you although i'm sure there might be some other reasons also. The layman in me always assumed you'd have enough in the tanks to get get you out of it, but you've dispelled that myth, thanks!

 

[mannej]

Is windshear on takeoff something that would affect the A380 or only the smaller aircraft ?

Report: Qantas B738 at Perth on Dec 4th 2012, windshear on takeoff run past V1

JB, how much time is there to react to something like this? Avherald does make it seem like there was very little margin to act with that one

 

[jb747]

Apologies if you've answered this already, but is there a set criteria for cancelling a flight based upon conditions at the destination?

I ask this just because I was pretty surprised when flights were still landing at PHE during the blue alert immediately prior to an imminent cyclone. I think the winds were gusting and approaching the 100km/h mark at the time. What are the maximum wind speeds you could safely land/take-off in?

Over the years I've seen some pretty interesting behaviour with regard to people pushing on in very suspect conditions.

I've diverted from London (to Amsterdam) when another airline (that many of you like) most definitely landed outside of the Boeing designated limits. We treat limits as absolute, whereas they consider themselves to be at least as good as the Boeing test pilots, and so consider them advisory only. In HK I taxied away from the runway and back to the terminal, having decided that I would not take off, only to see another airline go...and they'd recently lost an aircraft in similar conditions.

My employer has always relied on their Captains to make valid calls as to the safety of an operation, and there is no come back whatsoever at any safety based decision. Others either don't have that discretion, or don't use it. Some of the hiring practices now in use (i.e. using third party companies to supply pilots) makes it very easy to bring undue pressure to bear. That's something that a mature operation won't do, but I see plenty around that vary from cranky two year olds, to sulky teenagers...

 

[jb747]

How often do you run into this sort of situation - where you are faced with a thunderstorm, or low vis and no suitable ILS, and have no choice but to attempt the landing anyway? I guess you can either take that as a literal "you", or a wider "you" encompass the general population of commercial pilots. Whichever you think is more relevant / interesting

Me personally...I'll probably take the low fuel diversion, or perhaps park the jet somewhere unusual. Pushing below minima is generally a stupid thing to do. I'm pretty sure that Lion showed us what happens in Bali a few weeks ago.

The aim though is to keep a good track of what is happening, and to divert well before it turns to custard. If thunderstorms are even a vague possibility, I personally add lots of fuel prior to departure. If it starts to look shaky, then increasing speed and committing to an early diversion is often the easiest and safest option.

Fuel equals options, and if you aren't an accountant, the only time you have too much is when you are on fire.

 

[jb747]

When approaching a airport that you no longer have an alternative for (ie you're next to land) is it a concern for you that through something other than weather the runway became inoperable? The most obvious but of course unfortunate scenario would be some sort of incident on the runway with the aircraft ahead of you although i'm sure there might be some other reasons also. The layman in me always assumed you'd have enough in the tanks to get get you out of it, but you've dispelled that myth, thanks!

Always an interesting possibility, and especially problematic at places with only one runway. We occasionally look at unusual landings...like landing on a parallel taxiway, or landing as short as possible, and using maximum braking. Perhaps even having to land 'over' something. I recall landing the 747 sim on the light aircraft strip at Cairns, though I suspect the real aircraft would have gone straight through it.

You don't need incidents to happen on the runway though. Many years ago I had a flap malfunction approaching Wellington. The resultant configuration would not have allowed a diversion of any length, and it required much higher approach and landing speeds, which effectively meant the runway was now too short. Lateral thinking helps...