Flying the Airbus A380 – Takeoff!

Thank you to everyone who has been so kind about my posts on Twitter. I’m glad (most of) you find it interesting. However, the limited number of characters available per post makes explaining the more complex aspects of flying the A380 a little tricky! So I thought I would start a blog where I can give more detailed descriptions about all things A380….

So let’s get the A380 into the air shall we?

Before we go blasting off down the runway we have to perform a takeoff performance calculation using our inbuilt application.


This screenshot shows the takeoff calculation performed for a takeoff  from Johannesburg. So what do all the bits and pieces mean?

The first thing we do is select the airport, shown top centre of the screen in yellow. In this case FAOR / JNB. To the right of this selection we then choose the takeoff runway and which intersection we are expecting to use. Here, that is runway 03L and we are going to use the full length. The application displays the runway information immediately below. Quite a bit of detail here, but the main ones we are looking at are TORA – Take Off Run Available, here 4418m and whether there are any obstacles we need to be aware of, or let the application know about, in the area immediately after takeoff. There is also a small window below this information giving takeoff performance restrictions. This would detail items such as emergency turns we would have to perform should an engine fail during or shortly after takeoff. In this case, No Performance Restrictions Exist.

We then go through the process of loading information into the window on the left of the screen under Conditions. The first few are pretty obvious. We just type in the reported wind, temperature, pressure (QNH), runway conditions, and whether we are going to be using engine anti-ice. If you are not familiar with the flying definition of icing conditions, they may well come as a bit of a surprise. Here is the official definition we use:-

“Icing conditions exist when the outside air temperature on the ground or in flight is 10C or below and visible moisture in any form is present (such as clouds, fog with visibility of one nautical mile or less, rain, snow, sleet or ice crystals).”

There is also a further extension to this definition which covers the situation where there is no actual precipitation at the time, but the taxiways and/or runways have standing water, snow, ice or slush which could be ingested by the engines.

The reason a temperature of 10C can still cause engine icing is the cooling effect on the air as it is taken into the engine inlet. For the Rolls Royce Trent 970 engines fitted to BA’s A380s the engine anti ice system takes hot bleed air from the third stage of the High Pressure Compressor (simply put, centre of the engine) and uses it to heat the front part of the engine cowling (basically the silver bit you see at the front of the engine). More details on engines and compressors at a later date!

Back to the takeoff performance application. We next enter our expected takeoff weight. Here, 500.4 tonnes. Quite heavy! The next three items are the configuration, ie flap setting. We usually leave this in Opt Conf – optimum configuration, unless there is a good reason not to. Air Cond specifies whether we will be using some bleed air from the engines to power the air conditioning and pressurisation systems during the takeoff. This is similar to the anti-ice detailed above. Using some of the bleed air from the engines to power the air conditioning does slightly reduce the power available for takeoff. In some cases we can use either the APU (small jet engine in the tail) to power the air conditioning, or even perform the takeoff with the air conditioning systems turned off, to achieve maximum thrust. We currently use the APU to power the air conditioning during takeoffs from Hong Kong and Singapore as these present the highest takeoff weights for us on the British Airways network. For all other takeoffs we use engine bleed air.

Finally, most takeoffs are performed using Flex Thrust. Describing Flex Thrust could be a blog itself! So here is the shortened version. If we were taking off at the maximum weight the performance of the aircraft would allow on the day we would have to use maximum thrust. However, we usually take off at a weight below this maximum. It therefore makes sense to reduce the wear and tear on the engine by reducing the power below maximum. You don’t always drive your car with the accelerator on the floor do you? (Unless your name is Jenson Button!)

In simple terms, the maximum available takeoff thrust varies with outside air temperature (OAT). As the OAT increases, the air density decreases, so reducing the amount of power the engine produces. So let’s look at our particular case. We can see from the data we entered into the application above that the actual OAT for our takeoff is 16C. However, look at the number next to the green FLEX almost in the middle of the screen, in the Results window. It is showing 35C. So the application has determined that we can use an ‘assumed’ temperature of 35C for the engines for this takeoff rather than the actual temperature of 16C. By telling the engines to use this flexible temperature of 35C instead of 16C, they will not go to maximum power, and so reduce the wear and tear.

The A380 can operate over such a range of weights that the reduction in engine power required for takeoff can be quite large. The limit states that the takeoff thrust cannot be reduced by more than 40% of full rated thrust. This is a much greater reduction than allowed on most aircraft. But going back to Jenson and his car, although he will probably spend quite a proportion of his time when racing with his foot hard down on the accelerator, you would expect him to be far more lenient with his own car when driving on normal roads! This is exactly the situation when we are flying. We can use full power when needed, but it is far better for the engines if we back off a little from this when we can.

Don’t worry! We are almost there! In addition to calculating how much power we need to use for takeoff, the results window shows us our takeoff speeds and flap setting. V1 is the speed beyond which we are going to takeoff even in the event of an engine failure. VR is the speed at which we will rotate, ie pull back on the sidestick to lift the nose up. V2 is the takeoff safety speed. This is the minimum speed we must fly after takeoff. There are three possible flap positions for takeoff on the A380. Here, we are going to use the first one, Flap 1+F, which is the least amount of flap we would ever use. Other flap settings available to us are Flap 2 and Flap 3. These would normally result in lower takeoff speeds, but would have consequences for the rate of climb achieved immediately after takeoff. There is a balancing act to perform here, and the takoff performance application is usually left to decide the best setting. I will cover the specifics of flap settings and what they mean in a later blog….

Now we have all the information we need. We know how much power to use, which flap setting to use, and how fast we need to be going before we can fly. So let’s get on with it!

We line up on the runway and make sure everything is good for takeoff before moving all four thrust levers forward together to approximately 30% thrust. The A380 uses a thrust system called ACUTE to show how much power the engine is producing as a percentage of the maximum power available. (ACUTE = Airbus Cockpit Universal Thrust Emulator)


This is shown by the top dials on the screenshot above. In this case the engines are actually running at around 73% thrust as the photo was taken in the cruise. It is a little busy at takeoff to be taking photos of the instruments!

Once the engines have all stabilised at 30% we advance the thrust levers further into the FLX position. This tells the engines to produce the amount of power we previously calculated. The engines accelerate rapidly from 30% to the required, calculated thrust and off we go! If you have flown with us on our A380s you will, no doubt, be aware of this two stage engine acceleration. There are also a couple of other functions which prevent the engine from operating at certain rotation speeds during the takeoff roll which can result in there being more than one acceleration from 30% to takeoff power. The one which we see most is called METOTS (Modified Engine Take-Off Thrust Setting). It prevents the engine from exceeding 78% N1 below 35kts. This is an engine protection system to prevent fan instability. N1 is the actual rotation speed of the big fan you see at the front of the engine, expressed as a percentage. It is shown just below the ACUTE THR dials. We will often see the engine increase to a power just below the METOTS setting, then as the airspeed increases, a final extra push in the back comes as takeoff power is reached.

The other information on the screenshot above is the EGT (Exhaust Gas Temperature). This is the temperature of the air passing over temperature probes at the rear of the engine.

So now we are accelerating down the runway. The handling pilot (HP) will be spending most of their time looking out of the window, making sure the aircraft is tracking down the runway centreline using the rudder pedals to make very small changes to direction. The other pilot, or non-handling pilot (NHP), will be monitoring all the aircraft parameters very closely, especially the engine and flight instruments and looking for anything out of the ordinary.


This screenshot shows the other engine information. N2 and N3 are internal spinning components of the engine, FF is the fuel flow in kg per hour. The oil quantity is measured in quarts. The PSI is the oil pressure, then there are three vibration indicators for the three spinning sections, and finally an engine nacelle temperature dial. In many ways the NHP is the harder working of the two pilots at this stage as they are monitoring all these parameters while also making sure the HP is tracking the centreline properly, in addition looking at the flight instruments to make sure all the airspeed indications are accelerating correctly and all giving the same speed. The HP is just grinning from ear to ear as they control 500 tonnes of A380 as it accelerates rapidly down the runway!

At 100 knots airspeed, the NHP announces “one hundred knots”. The HP looks down and checks their airspeed indicator, makes sure it also reads 100 knots, and states “Checked”. We use 100 knots as a speed below which we would be ‘stop minded’ if we have a problem, and above which is it probably better to continue the takeoff and deal with a problem in the air due to the problems associated with stopping from high speed. So, from this point on, unless we have a major problem, we are not going to stop. Once we reach V1 an automated voice will announce “V1”. From this point on, no matter what problems arise, we are going flying as there is insufficient runway left to stop. In our case we still have 16 knots left to accelerate before the NHP announces “Rotate” at Vr. Now the HP gently pulls straight back on the sidestick, watching for the horizon to drop out of view at a constant rate, and briefly glancing at the flight instruments to ensure all is well. We want to rotate the aircraft at around 3 degrees per second, initially aiming at a climb-out attitude of around 12.5 degrees. The initial rotation takes a little time to establish, but once the nose has started to lift the pitch rate remains fairly constant for a given sidestick input.

We are now flying! (The grin just got even wider!). The NHP announces “Positive Climb” to which the HP announces “Gear Up”. The NHP moves the gear lever then all 20 mains wheels and 2 nosewheels are lifted up, landing gear doors close, and there is a little ‘squeak’ from the nosegear area as everything stops moving, which never fails to make me smile! It is almost as though it is saying, very quickly and excitedly, “Up!”

Once all the wheels are packaged away there is a very noticeable drop in noise level. It is amazingly quiet in the cockpit.

We continue flying away from the ground until, normally, at around 1000 feet above the airfield the HP will lower the nose, reduce the thrust to climb thrust, and start to accelerate to S speed. This is the speed, shown on the airspeed indicator, at which the flaps can be retracted completely. The HP will ask for this to be done by stating “Flaps Zero” (sometimes followed by “Please” by those who have been brought up correctly!). The NHP repeats “Flaps Zero”, checks the speed is correct, and moves the flap lever. Now we can accelerate to the usual climb speed of 250 knots when below 10000 feet, and once above that, a typical climb speed of around 330 knots.

Then it is time for something very important. A nice cup of white tea, no sugar please!!!


So how much fuel do you think the massive Rolls Royce engines on our A380 use on takeoff?

Well, on the last takeoff I flew the flow rate of fuel into each engine on the runway was 8200 kg per hour! So the total flow rate of fuel used on that takeoff was 32800 kg per hour! Considering how much power is being produced, and how heavy the aircraft is at takeoff, it is quite remarkable how quiet it is both inside and outside.

Stopping! All about brakes and BTV – Brake To Vacate

I hope you enjoyed the first blog post. Thank you to all those who sent feedback!

Operating an aircraft isn’t all about what goes on in the air. Stopping is just as important as going. Now, before we start considering this, a warning…. This is a fairly long piece! So go and make a coffee, get comfy, and we will be fine. Alternatively, read this in bed if you can’t sleep and be prepared for the shock when whichever device you are reading it on hits you in the face when you doze off!

Contrary to a fairly common belief, it is the wheel braking system which provides most of the retardation for aircraft. What about reverse thrust? Well, the thrust reversers on the engines are there mostly to help the wheel braking systems but are not the primary source of braking. Indeed, Airbus originally planned for the A380 to not have any engine reverse thrust. In the final version of the aircraft which went into service, reverse thrust is only available on the inboard engines.

So our main source of braking is wheel braking. But which wheels are fitted with brakes? Not the nosewheels, they are used exclusively for steering. And what may surprise some people is that not all the main wheels on the A380 are fitted with brakes. The most rearward wheels on the main undercarriage are just rolling wheels. You will see in the photo below that the wheels on the right are much cleaner due to lack of brake dust.

Big wheels!
Big wheels! (Captain @Colin__Dick and I inspecting the undercarriage)

Braking is normally carried out using an autobrake function. This also includes a rejected takeoff (RTO) function which applies maximum braking if the thrust levers are closed once above 72 knots during the takeoff roll. Many aircraft have an autobrake system. These are normally armed during the approach and landing briefing, which is typically carried out just prior to starting the descent. Most autobrake systems are set using either a numbered system, where higher numbers giving a greater braking force, or a descriptive system, such as that used on the A320 series, where either LOW or MEDIUM braking will be selected for landing.

Airbus introduced a revolutionary (sorry!) new system on the A380 called Brake To Vacate (BTV). It is optional on the A380, but fitted as standard on the A350. This advanced system allows the landing pilot to pre-select the runway exit they wish to take, and the aircraft will apply automatic braking as appropriate to allow this to happen in the minimum time. The system is quite complex, but works exceptionally well. We use this system for virtually every landing in British Airways as it allows us to pre-plan our exit from the runway, reduces brake wear, and is very comfortable for our passengers.

So how do we use BTV? Firstly we set up the aircraft systems for our expected landing runway. In this example, we will use runway 24R at LAX. Initially we need to look up the airfield and the specific runway on our LIDO airfield charts. You will remember from the previous blog that we have to make sure we only use those runway exits and taxiways which are colour-coded green, ie. suitable for the A380. Here is the runway exit chart for LAX runway 24R.

FullSizeRender 4

So what is this showing us? Runway 24R is the runway at the top of the screen. You can actually only see the label for runway 06L here, but that is the same runway from the other end! Do you know how the numbering system works for runways? If you do, skip to the next paragraph. If not, it is actually quite simple. The two numbers are the first two numbers of the compass heading along which you will be pointing when looking down the runway. So in this case, 24 means the runway is set at about 240 degrees on a compass. Runway 18 would be pointing south, runway 09 pointing east etc. Runway 09 would also be runway 27 if you were using it in the opposite direction. If there is a letter after the numbers it means the airport has more than one runway pointing in the same direction so they are differentiated by R for right, L for left, and C for centre. I hope that is clear!

Just to the right of the 06L label on the chart you will see a green runway exit labelled AA. This is the usual exit we use at LAX when landing on 24R (The chart is orientated to the north, so when landing on runway 24R we will be moving from right to left down the runway as shown on this chart). The chart also clearly shows the green colour-coded taxiways the A380 is able to use. Anywhere not coloured green is out-of-bounds for the A380. So, for example, we could not use exit Z, the one to the right of AA. You will see on runway 24R itself there is some writing – 2721 G 46. This indicates the runway is 2721m long, has a grooved surface, and is 46m wide. 46m is a typical runway width. Some are 60m wide. Interesting to think the wingspan of the A380 is almost 80m and the distance between the outboard engines is 51.4m!

With runway 24R being 2721m long, a typical length, that should be more than sufficient for us to land on. But let’s make sure! For that we use the Landing Performance app installed on our Onboard Information Terminal (OIT). Below is the calculation performed for our flight. (Note that since I took the photos of the landing performance app and OANS displayed below, the runway length at LAX has increased by 1m! Thought I’d better get that in before the eagle-eyed among you did!)

Landing performance calculation
Landing performance calculation

Lots of numbers here! To summarise, on the left we enter the landing conditions and aircraft configuration. Top, centre, we select an available runway. We then press the ‘compute’ button, and after a few seconds the information in the ‘Results’ window appears. In this case the results show that for landing on runway 24R at 344.4 tonnes we should use FLAPS FULL, our landing distance LD will be 1656m. This is the minimum landing distance required using the autobrake setting we have selected, in this case, Lo braking. We use Lo braking as an indicator to start with as this is the most comfortable braking from a passenger point of view. This distance then has a 15% increment added to allow for handling and other variations on the day (the 1656m figure is that calculated as the best which would be achieved by the Airbus Test Pilots!), giving a Factored Landing Distance of 1984m.

The Stop Margin is how much of the runway will be left when the aircraft comes to a halt. GA Gradient is concerned with aircraft performance in the event of a go-around, so is not something we are considering at the moment. Finally, the figure towards the bottom right, VAPP, is the final approach speed, 132 knots in this case. Despite the A380 being such a massive aircraft, the landing speeds are comparable to A320s and the like.

We have determined we need 1984m of runway to stop the aircraft. We know from our LIDO chart that runway 24R is 2721m long, so that is fine. Now we need to determine which exits we are able to make. So lets display our OANS – the Onboard Airport Navigation System. This is effectively a ground-based satnav for the aircraft. It can either display our actual position on an airfield, or we can look up any airfield in the database for planning purposes.

Select the landing runway
Select the landing runway

In this diagram we have selected runway 24R, as indicated by the numbers being shown in blue. The OANS then displays the information it contains about the runway. Remember the 2721m runway length shown on the LIDO chart? OANS shows 2720m. This is one of our crosschecks. If the LIDO chart and OANS disagree by more than 35m, we are not allowed to use BTV. But here we are fine.

You will see two labelled magenta lines drawn on runway 24R. WET and DRY. You will not be surprised to hear that these lines show the position BTV braking has calculated it can stop the aircraft on a wet or dry runway. If possible, even on a dry runway, we would select a runway exit  beyond the wet line. Again, this is mainly due to passenger comfort, but also means the braking system isn’t working hard. Right in the centre of the above OANS display you will see a magenta up arrow with a magenta down arrow directly above it, and a small magenta dot in between. This is the trackball cursor. We would now move this over the top of exit AA, shown to the left of the screen, and beyond the wet line, and select this exit. This results in the display changing as shown below.

Exit AA now selected
Exit AA now selected

Exit AA is now shown in blue, and the display at  the top left shows EXIT AA 2145m, ROT 80″, TURNAROUND 100’/120′. So, exit AA is 2145m along the runway. This is more than the 1984m we calculated we would need earlier using Lo autobrake, so that is fine, and reconfirms the calculated lines BTV drew on the OANS. ROT stands for Runway Occupancy Time. In this case, BTV has calculated this to be 80 seconds for us to vacate the runway at exit AA. TURNAROUND is the time in minutes it will take for the brakes to have cooled below 150C, which we would need before performing another takeoff. There are two numbers. The lower one is the time if we use maximum reverse thrust on landing, the higher number is for reverse idle.

The last thing to do is arm the system using the autobrake knob.

Now all we have to do is land the aircraft in the right place at the right speed and BTV will control the deceleration for us. It is a superb system. It can be a little unnerving the first few times you use it! This is because it constantly monitors the aircraft speed and position on the runway and, unless you have asked BTV to enable you to vacate at a limiting exit, only applies a noticeable amount of braking fairly late on in the landing roll. This allows the aircraft to naturally decelerate after landing using air braking and reverse thrust, so minimising the work the brake system has to do.

Once it has initiated braking, BTV targets a constant (passenger friendly) deceleration rate to achieve a speed of 10 knots, 65 metres from the selected runway exit. However, if the exit chosen is within 300 metres of the runway end, this changes to a target of 10 knots at 300 metres from the end.

All sounds nice and rosy so far doesn’t it? So what happens if we land further down the runway than we planned and BTV calculates we cannot stop by the selected exit? Firstly, don’t land too far down the runway in an A380! (or any aircraft for that matter). Better to throw away a poor approach and do it again than try to make the best of a bad job. However, if the landing is only slightly beyond the normal landing point and a limiting exit has been chosen, or conditions on the ground dictate that the original exit now cannot be achieved because the deceleration rate is not what was expected, what happens next? Firstly, remember the best piece of advice ever given in The Hitchhiker’s Guide to the Galaxy. Don’t Panic!

On landing, the wet and dry lines displayed on the OANS are replaced by a single green STOP line. This shows where the braking system believes the aircraft will stop. It is constantly updated during the landing roll. If the green stop line goes past the BTV selected runway exit it turns amber, as does the label for the selected exit, a ‘triple click’ sound is heard, and EXIT MISSED is displayed. This is not too much of a problem in this case, as there is still sufficient runway to stop the aircraft, just not to vacate it at the point initially selected. However, what happens if the green line goes past the end of the runway?

This would activate the ROW/ROP – Runway Overrun Warning / Runway Overrun Protection systems. These are quite brilliant systems which are worthy of a blog all of their own. And if you have made it this far through this one, you are probably ready for a rest now! So we will cover those at a later date when we have gone through how to operate the A380 when everything is working well, to how we deal with situations where things aren’t going quite so sweetly….!

I hope the above has helped you understand how the superb BTV function works and enables us to bring the aircraft down to taxi speed in the most comfortable and efficient way possible. If there is anything which is not clear, or you have any other questions, please let me know via @DaveWallsworth on twitter and I will do my best!

If you enjoyed reading this and the previous blog, please pass on a link to anyone you think may be interested, and let me know what other aspects of flying the A380 interest you.

Best wishes, and happy flying.