Technical stop duration

[Yan104]

Hello,

It's been a hell of a time since I didn't been back on the community forums, after a few personal concerns, and today I want to launch a topic that raises my curiosity. I would like to remind you that as a French speaker, my English might not be the most understandable, which is why I would ask you to be patient and understanding. I've noticed that during a report on an Air France A380, just arrived from a flight it seems it assured on Los Angeles, therefore of a duration of 12h of flight, it was programmed 3h after his park for a new flight on New York!!.... This time of stop seemed rather short to me: personally, I play a simulation of airline management, and for my long-haul planes, I set a stopover of 50% of the duration of flight that they make, that is to say that if my A380 makes a 12-hour flight, I leave it parked at destination for 6 hours before its return flight time, this in my opinion to not keep the reactors operating on stresses too sustained, potentially increasing the risk of failure. I would like to know whether there are any technical constraints or other factors which determine the minimum duration of technical stop for different types of aircraft?

Thank you for your answers.

[wiggy]

Bonjour

I set a stopover of 50% of the duration of flight that they make, that is to say that if my A380 makes a 12-hour flight, I leave it parked at destination for 6 hours before its return flight time,

You'll regularly see 2 hr or less stops routinely programmed at airports for Long Haul heavy types these days. and that's mainly due to the time it takes for the cabin to be cleaned and galleys to be refilled. The aircraft systems do not need to "rest" so the actual technical turnaround might just be a refuel and the engineers checking the engine oil levels and walking around the aircraft to check the gear and airframe for any signs of problems.

As an extreme example the shortest turnaround I've seen for a 747 was just under 40 minutes ( brakes on - one pax off (medical) - top up of fuel, check of engine oils - sign paperwork- push back- depart).

[chevvron]

When flying Heathrow to Rio or return (BA 777), there is a tech stop at Sao Paulo which last about 1 hour.

[wiggy]

Ah yes, I can't recall if all the pax have to get off on that transit and then reboard or whether those "going through" can stay onboard - they used to be able to and that speeds the tech stop up. I've also seen on occasions 1 hour transits done in SIN on the LHR/Oz routes, and that is somewhere where everybody has to get off, but the key to that one working so quickly is having efficient ground staff and an efficient terminal/gate layout.

[B2N2]

Financial reasons.
Airplanes cost money sitting on the ground.
Just for the fun of it:

Airplane cost $240 million new
Depreciation to zero: 20 years

That's $12million/year just in depreciation.
$32,876/ day
$1,367/hr
$22.83/min.

This is just depreciation.
Doesn't include maintenance cost and insurance over 20 years.
Long haul airplanes can spend up to 16-18hrs in the air in a 24hr period.
Two legs plus turn around.
Some passengers flights are conducted at a loss and some may only make $300-$500 profit.
On an entire flight.
Any delay costs money.
Big money.

[AerocatS2A]

Curious what airline management sim do you play?

[B2N2]

I don't.
I fly them.
But I'm a numbers geek
https://en.m.wikipedia.org/wiki/Boeing_747

https://en.m.wikipedia.org/wiki/Airbus_A340

A 747-400 D check is $2.9 Million and that's every 4-5 years.

[chevvron]

Originally Posted by wiggy

Ah yes, I can't recall if all the pax have to get off on that transit and then reboard or whether those "going through" can stay onboard - they used to be able to and that speeds the tech stop up. I've also seen on occasions 1 hour transits done in SIN on the LHR/Oz routes, and that is somewhere where everybody has to get off, but the key to that one working so quickly is having efficient ground staff and an efficient terminal/gate layout.

At Sao Paulo, all passengers for Rio stay on board.

[Yan104]

Hi guys,

Sorry I could not get back to the forum earlier because I was busy these days ... Thank you in any case for your interventions ...

AerocatS2A

Curious what airline management sim do you play?

In fact, at first I started playing Manager Manager, but I did not find it fairly realistic to look at it, and as I went through it, I came across a community simulating with an unprecedented level of detail the Life of a real company and all its management parameters !! ... I give you here an overview of the characteristics of Airwaysim(https://www.airwaysim.com/Information/Features).

wiggy

You'll regularly see 2 hr or less stops routinely programmed at airports for Long Haul heavy types these days. and that's mainly due to the time it takes for the cabin to be cleaned and galleys to be refilled. The aircraft systems do not need to "rest" so the actual technical turnaround might just be a refuel and the engineers checking the engine oil levels and walking around the aircraft to check the gear and airframe for any signs of problems.
As an extreme example the shortest turnaround I've seen for a 747 was just under 40 minutes ( brakes on - one pax off (medical) - top up of fuel, check of engine oils - sign paperwork- push back- depart).

It seems to me I have read I do not know where the recommendations of the manufacturers to spare the reactors and avoid the risk of breakdowns. This concerns the critical phases of take-off and initial climb to the cruising level: I understand that 99% of the thrust should never be used during taxiing on the take-off runway, and that once the climb has been engaged The pilots must progressively reduce the thrust to stabilize it to a little more than 80% in cruising ... To apply too frequently the reactors to their maximum power on takeoff can be cause of breakdown ... From there I deduced by extension That the reactors had to be spared after sustained efforts like 12 hours of flight, to avoid too close cycles of maximum efforts on takeoff ...
On the other hand, it is true that I did not take into account other stopovers operations such as passenger cabin cleaning, refueling and food, and loading / unloading luggage. On other forums I could see schedules inserted in the documentation of the manufacturers on the ground operations, but that I did not know how to interpret correctly. I also know that now the kerosene feeding of airplanes is done by an underground network of pipelines leading to the locations of airplanes: the fuel is then pumped from the ground and directly injected into the tanks of the planes, without needing a tanker truck . How long does it take a full tank of gas to run a bi-reactor? Does it depend on aircraft types and sub-types (B777-200 / 300, A330-200 / 300 etc)?
On the other hand the time of turnaround you quote me for the B747 of 40 minutes, please with a sick passenger to evacuate, seems completely unimaginable !! ... This delay is already too fair for the A320 and B737 of low cost airlines !! ...

chevvron&wiggy

When flying Heathrow to Rio or return (BA 777), there is a tech stop at Sao Paulo which last about 1 hour.

wiggy

Ah yes, I can't recall if all the pax have to get off on that transit and then reboard or whether those "going through" can stay onboard - they used to be able to and that speeds the tech stop up. I've also seen on occasions 1 hour transits done in SIN on the LHR/Oz routes, and that is somewhere where everybody has to get off, but the key to that one working so quickly is having efficient ground staff and an efficient terminal/gate layout.

Chevvron and Wiggy, here is a rapid stopover due to an insufficient range of this airplane which does only suppose I think usual checks and the refueling in kerosene of the plane ... In general this n Is that at the final destination of the plane one prepares it for a new flight after the passengers left it ...

B2N2

Financial reasons. Airplanes cost money sitting on the ground. Just for the fun of it:

Airplane cost $240 million new
Depreciation to zero: 20 years

That's $12million/year just in depreciation.
$32,876/ day
$1,367/hr
$22.83/min.

This is just depreciation. Doesn't include maintenance cost and insurance over 20 years. Long haul airplanes can spend up to 16-18hrs in the air in a 24hr period. Two legs plus turn around. Some passengers flights are conducted at a loss and some may only make $300-$500 profit. On an entire flight. Any delay costs money. Big money.

B2N, I am aware of the costs involved with airplanes for a company, and in the report I saw on the Air France A380 I learned that its parking cost the company just over $ 2,000 / H, not including the other airport charges of destination airport and base airport of company ... But concerning the long haul flights, for flights at a loss or with ridiculous profits, the companies of the emirates (Qatar Airways, Etihad etc ...) have competitive advantages that cause prices to be broken compared to traditional companies as well ...

To get back know to my subject, can we standardize the turnaround time of some planes like ATR, B737 / A320, B767 / A330 etc ...?

[wiggy]

It seems to me I have read I do not know where the recommendations of the manufacturers to spare the reactors and avoid the risk of breakdowns.

Yes, there are limits on the amount of thrust used in various stages of flight, usually most important in take-off and climb. Once in the cruise the engines are running at or below "Maximum Continuous Thrust" and are then able to run almost forever as long as they have fuel and oil. Despite what you have been told or what you have read they really really do not need to be rested/spared after a flight, they really really don't.

Chevvron and Wiggy, here is a rapid stopover due to an insufficient range of this airplane which does only suppose I think usual checks and the refueling in kerosene of the plane

Um,

1. Last time I did the Sao Paulo stopover chevron mentioned was not due to limited range, but he may be more up to date on it than I am.

2. The SIN transit is mainly due to range but even so it is not just "usual checks and the refueling". Some passengers leave the flight in SIN, others some join it, so on arrival everybody gets off the aircraft and heads into the terminal, the cabin gets a quick clean, there's some baggage unloading/loading, and then there's full boarding again as passengers get on, so it is much much more than just a fuel stop. I've personally seen that transit done in about an hour or a little more on several occasions...I would say that is just about as fast as you can do a full turnround on a 777 or a 747 and to achieve that everything has to work perfectly.

On the other hand the time of turnaround you quote me for the B747 of 40 minutes, please with a sick passenger to evacuate, seems completely unimaginable !! ..

I was one of the co-pilots involved and unimaginable or not it did happen. It was only possible that quickly because we just needed to get just one passenger off, not everybody, didn't need to reboard, etc....and there was no need to rest the engines...

I know you will see some very long turnrounds at times, but that will be done for several reasons: to perhaps fit in with schedules, to fit in with ATC slots or night slots at departure/destination (you see that with QF 380s at LHR and BA's 777 at SYD), or allow slightly more time for scheduled maintainance on the aircraft, which it will need every few sectors ...but in almost 30 years of flying Wide bodied aircraft on often Ultra Long Haul flights I have never heard of turn rounds being extended simply to let the engines have a rest.

[chevvron]

Limited range? You fly right past Rio to get to Sao Paulo then come back an hour or so Later!

[wiggy]

Ah that's how I remember it working... I was wondering if somewhere had moved and nobody had told me...