The Aircraft Turnaround: What Goes on Between Flights
Just more than 10 hours after leaving Los Angeles, the Boeing 787 Dreamliner finally touches down into London Heathrow. It's a few minutes after 1 p.m. On board, the passengers are nearing the end of their journey. Family await some of them, business meetings with clients await others. For the pilots and cabin crew, it's the end of another long night shift. Bed is calling.
However, for the aircraft, there is little time for rest. In just two hours time, it's due to embark on another long journey — this time 11 hours east to Shanghai.
In that short time frame, the current load of passengers and cargo need to be offloaded, the aircraft needs to be cleaned and re-catered before the new passengers and crew board for the next flight.
How does this all take place? What really goes on after you leave the aircraft and before you board? Here's the low down to all that goes on during the aircraft turnaround.
Inbound Aircraft
Before the aircraft touches down, ground staff are already preparing for its arrival. The parking stand has been allocated by the airport and the team of staff led by the aircraft dispatcher are ensuring that it is ready for the arrival of the inbound aircraft. The stand area is checked for any debris that may cause damage to the aircraft and all ground equipment is parked clear of the aircraft maneuvering area.
When the stand is clear, the parking guidance is turned on. In order to park accurately, pilots use laser-guided systems to guide the aircraft to the exact spot in which it needs to stop. For more on how this is done, check out my article, Parking a 200-Tonne Airliner — How Pilots Move a Plane Around on the Ground.
As the aircraft turns onto the stand, the guidance system counts down the distance until the stop point. The pilots take a moment to ensure that the parking brake is set, the APU is running and the doors have all been set to manual before then shutting the engines down.
Outside, the ground staff hear the engines start to wind down and the front engine fan start to slow. However, they are waiting for one more thing before they know it's safe to approach the aircraft. On top of and below the aircraft is a red flashing light, the beacon. When the pilots switch this on, it's a sign to those on the ground that it is not safe to approach the aircraft. This is normally because the engines are running or are about to be started. As soon as the beacon is switched off, the ground crew spring into action.
The first thing the ground crew do is chock the aircraft. This involves placing large rubber or wooden wedges around the aircraft wheels to ensure that it doesn't move inadvertently. They also place cones at strategic points around the aircraft to ensure that ground vehicles don't drive into the engines or wings. As the 787 is an electricity-hungry aircraft, two ground power sources are connected to the left hand side of the aircraft, just behind the nose wheel.
When the engines are shut down, the aircraft uses electrical power generated by the APU — the small engine in the tail. That said, sometimes the APU isn't working so the aircraft needs to connect to ground power before shutting the engines down. This can take a little time as the ground staff need to approach the aircraft with the ground power connection whilst the engines are still running. In dangerous situations like this, things are done slowly and methodically to ensure the safety of those on the ground.
Once the aircraft is chocked and the engines shut down, the air bridge is moved toward the aircraft door. Whilst this is normally done fairly promptly, sometimes it can take some time if the ground power needs to be connected before shutting the engines down. With the aircraft door open, the passengers can start to disembark.
Clever positioning
Have you ever boarded an aircraft via an air bridge or steps on the right-hand side of the aircraft? I'll bet you a good sum of money that it's a no. If so, I'd like to hear about it!
When designing an aircraft, manufacturers spend a great deal of time working out how it will be serviced whilst on the ground. They plan the vital access points, such as boarding doors, cargo doors and water filling points so that they don't interfere with each other.
The basic principle is that passenger boarding/disembarking and refueling are done on the left hand side, and all other ground services, such as catering and baggage and cargo loading is done on the right-hand side.
This means that the various servicing jobs can be carried out at the same time without interfering with each other. This reduces the time needed to turn the aircraft around, meaning that it can get back to earning money in the air just as soon as possible.
The Offload
Baggage and cargo
With the passengers heading off the aircraft and up into the terminal, on the ground, the staff have opened the cargo holds and are preparing to offload the baggage and cargo. The 787 has two holds — one forward and one aft. Whilst you may casually sling a suitcase in to the boot of your car, loading and unloading an aircraft is a much more technical process.
The baggage and cargo are carefully loaded to ensure the aircraft is kept balanced or 'in trim'. Depending on the load, the ground staff may have to unload the contents of one hold before they start on the other to stop the aircraft from falling back on its tail.
Toilet servicing
It seems to be a common myth that when flushing the toilets on an aircraft that the 'contents' are vented to the outside air. I can confirm that this is categorically not true. What does happen is that the contents are taken via a system of pipes to a waste tank in the back of the aircraft. At the end of every flight, this tank has to be emptied by a specialist operative and vehicle.
A pipe is connected to the aircraft and the contents of the waste tank are emptied into a vehicle. Probably not the most glamorous job at the airport but someone has to do it.
Cabin servicing
As the last passenger leaves the aircraft, an army of cleaners and caterers are primed, ready to swarm the cabin. Bins need to be emptied, toilets need to be cleaned and rubbish needs to be picked up off the floor. In the economy cabin, blankets need to be collected and in the business-class cabin, pillow cases need changing and duvets need replacing. With more than 200 passengers after a 10-hour flight, there's lots of work that needs to be done to make the cabin presentable again.
Catering
At the same time, catering trucks arrive at the doors on the right-hand side of the aircraft, adjacent to the galleys. During the flight, whatever comes out of the food trolleys must go back in.
A tip for passengers to be helpful for crew: Piling all your trays up actually makes life more difficult for them. If you can return your tray to how it was when you received it, it's much easier for them to slide them back into the trolley.
With more than 400 meals worth of trolleys to unload, there's some serious work to be done. Once all the trolleys and canister boxes have been removed, it's time to start preparing for the next flight.
The Onload
It's now 70 minutes until the flight is due to depart for Shanghai. The passengers are all checked in and are starting to head toward the boarding gate. The pilots and cabin crew have conducted their preflight briefing and are making their way to the aircraft. 'Above and below the wing', or airline speak for the activities on the ground and in the cabin, preparations are now underway for the departure.
More food and drink
With more than 400 meals to serve on the 11-hour flight to Shanghai, there's plenty to be loaded. However, if they were all loaded in a haphazard fashion, the crew would find it nigh on impossible where to find things. As a result, the caterers know exactly in which stowage each trolley and canister go. Once on board, the crew immediately know where to find what they're looking for.
Refueling
The route between London and Shanghai is around 5,750 miles. Older aircraft types of aircraft such as the 747 would need just under 100 tonnes of fuel to do this route. However, the efficiency of the 787 means that just 60 tonnes of fuel is needed.
For a full load of 220 passengers, this equates to about .01 gallons (45 milliliters) of fuel per passenger, per mile. Far more impressive than any petrol road car. For more on how we decide how much fuel to take, check out my previous article, How Do Pilots Know How Much Fuel to Take on a Flight?
That said, getting 60 tonnes of fuel into the wings of the aircraft takes some time. Once the pilots have completed their briefing in the report center, their decision on the final fuel is passed onto the refueler. Around an hour before departure, the fuel begins to be pumped into the aircraft's fuel tanks.
Drinking water
During an 11-hour flight, there will be plenty of cups of tea and coffee drunk — not least by the pilots. In order to provide for this and to keep the water flowing in the bathrooms, around 185 gallons (700 liters) of water are loaded for the flight.
A small truck containing potable water connects to the underside of the aircraft toward the rear and pumps in water to be used for the flight ahead. The tank actually has capacity for more water, but like with anything aviation, weight is everything. Carrying an extra 79 gallons (300 liters) of water around over hundreds of flights a year will add significantly to the overall fuel bill.
Baggage and cargo
Loading an aircraft is very much like balancing a seesaw. Load too much weight at the back and the aircraft could tip back onto its tail. Load too much at the front and the pilots will struggle to get the nose into the air on takeoff. There's a fine balance to strike.
As a result, the loading of the aircraft is carefully calculated by the airline's planning department. Ground crew are told exactly where each container of baggage and cargo must go in the holds to ensure that the aircraft is in trim when it leaves the gate.
Engineering checks
Before every flight, engineers give the aircraft a once-over. Engine oil levels are checked and minor defects are dealt with. Each aircraft has a detailed list of tasks, which must be carried out in a particular time window. Some of these have to be done before every flight, some every day and others every week.
If any significant problems are found, they are dealt with in the appropriate way. If it's permissible to depart with them in accordance with the MEL, they are detailed in the aircraft technical log. If it's a more serious issue, there may be a delay to the flight. If it's not safe to depart, the aircraft simply won't leave. Safety is the most important factor.
Crew and passengers
Around one hour before the departure, the crew arrive at the aircraft and quickly spring into action. The cabin crew check their safety and emergency equipment and carry out a security to check to confirm that nothing untoward has been left behind from the previous flight or by ground staff. In the galleys, meals are counted and catering supplies are checked.
When the crew are happy that the cabin is ready for passengers, with the permission from the captain, it's time to start boarding the passengers.
Meanwhile, in the flight deck, the pilots perform the initial checks before setting up the aircraft for departure. The route is loaded into the Flight Management Computer, the predicted winds are downloaded and a departure briefing is completed.
The captain signs the legal paperwork pertaining to the loading of the aircraft and hands copies to the ground staff. It's almost time to go.
The Final Few Minutes
As the clock ticks down to the departure time, the last of the bags are loaded into holds and the hold doors are closed. The pilots start the APU to provide the aircraft with its own electricity and the ground power is disconnected.
The pushback tug positions itself in front of the aircraft, ready to clamp onto the nose wheel and push the aircraft from the gate.
With seven minutes to go, the passenger boarding door is closed and the air bridge is the final ground connection to be removed. It's time to go.
Bottom Line
Preparing an aircraft for flight is a complex process. Coordinating multiple teams of people to complete their jobs in a timely and safe fashion takes some work. Without any one of those seemingly small links, the whole process will break down.
The aircraft dispatcher is key to all this, making sure that the turnaround works like clockwork. Delays to any part of the turn could impact the on-time departure of the flight leading to a late arrival at the destination, potentially resulting in missed connections.
Next time you are sat at the gate waiting to board a flight, take a look out of the window and see what's going on. There's more to it than you think.