Aircraft to fly in formation 1.8 nm apart to save fuel like geese do
 

https://www.telegraph.co.uk/news/sci...save-fuel.html
Is this mad, or what ? Never mind the obvious, what about TCAS for a start?

Geese normally have TAs disabled, so not an issue.

I have seen geese myself meany times and assumed that there was an efficiency gain.

Turns out that 12% fuel saving has been achieved in tests with A380s. I assume that is for the following aircraft.

https://en.wikipedia.org/wiki/Formation_flying
"After A380s tests showing 12% savings, it launched its 'fello'fly' project in November 2019 for test flights in 2020 with two A350s, before transatlantic flight trials with airlines in 2021."

"Certification for shorter separation is enabled by ADS-B in oceanic airspace, and the only modification required would be flight control systems software. ... Commercial operations could begin in 2025"

Decent looking article here - https://aviationweek.com/dubai-air-s...lying-together

Will it be mandatory for the following pilots to "honk" to encourage the lead aircraft?

Only when stacked. :E

Jokes aside, it seems a rather impressive saving just by flying closer and modifying the software.

Airbus estimates that the following aircraft can save 5-10% of fuel by flying 1.5-2 nm behind the preceding one. “This is not at all about formation flying,” Bour-Schaeffer stressed. “[The concept] has huge potential and is a very tangible solution. The air is quite smooth and therefore it is practical. There is no impact on passenger comfort.”
From the Aviation Week link.

Not mad, a quite old idea in fact possibly reactivated today due greater automation of flight controls .
The military used this phenomenon already in WW1.
TCAS is not an issue , RAs will only be initiated if tacks converge, not parallel. System only works with RAs coupled to FD which is already the case on the A380/350.
For ATC, also not an issue as they will it will be considered a formation flight ,which means separation is the responsibility of the crews , not ATC..
Smooth air is a prerequisite of course, and how to predict that with accuracy over the oceans is THE question for me.

Our cheap flights will get cheaper they just slot in behind someone else :-)

Gatwick doesn't need to move its spare runway 10m to the north, then.

ATC should change - speedbird 123, easyjet 456 and ryanair 789 you are all cleared to Malaga......

Stick to the aerodynamics of planes with fixed wings in arguments. Likening any effects to geese formation flying is an aberration and a presumption.

I had always thought that geese formations were to prevent the constant leaking of spent fuel from the lead geese to get in the eyes of the trailing ones. The geese are dependent on their line of sight to avoid wing tip to wing tip affects, hence the V
.

So how will they get into formation in the first place without some burning lots of fuel orbiting ?

Well, that's 60 years of Radar separation standards going out of the window. Makes you wonder why we bothered to impose 3 or 5nm. Still, it is good to know that cherished, & strictly applied, separation standards were all a complete waste of time. All those airmisses/airproxes which SRG wasted their time investigating. If only they had realised that those sort of standards could have been dismissed so easily. Glad I am out of it.

2002...
 

Well, it's 17 1/2 years since that article was published and it still hasn't happened, so I shouldn't get to excited by it!

lol yes...

The Yanks tested that with their C17's and found it was about 1000m away to hit the perfect spot:

And another article from Aviation Week about it

Scoff as you will but this has been seriously investigated by Airbus for some time to overcome the obvious issues raised above of TCAS etc. Autopilot ranging is pretty straight forward technology. If they can measure sub millimetre distances between two satellites to infer gravitational anomalies in the earth's surface, keeping two aircraft 3000m apart aint hard.

The bigger commercial issues will be getting the aircraft to depart simultaneously to formate (and not wasting time loitering for the other aircraft to join) and sorting out who gets the credits in a multi company formate. As a leader do you get X nm of leading credits that you can spend in tow with another aircraft from any company...?

Clearly the savings are greater over longer routes. Two aircraft ex LHR to MEL and SYD could stay in formation for say 18 hours then split at the last 45 mins. Similarly in reverse to European destinations. 15% fuel savings are huge, equivalent to NEO engines once more. That's a lot of pax that equals $$$$.

> Turns out that 12% fuel saving has been achieved in tests with A380s. I assume that is for the following aircraft.

Analysis of drafting between bicycles shows that there is also a small advantage to the leading vehicle. Its because the partial vacuum behind the leader is partly filled in by the following vehicle.

And on arrival, number 2 plane then has to use up fuel orbiting while waiting for the lead goose's wake turbulence to go away, and leave space on the runway/taxiway to move around.

Weather avoidance would be interesting.

Just imagine the organisation and logistical problems it would ttake to get just two long-haul airliners to do this,not to mention inter-company rivalries.
But to get a group of them?
What routes are dense enough to do this?
It'd take hours to get the formation together!
And the press hysteria about collision risk?

I checked the date, it's nowhere near April. What's going on? Something brought on by all those mushrooms this fall?

Okay, what do you mean by fly "1.8 nm apart"???

The article says:
I suspect they'd have to fly very close together for maximum fuel savings.

Look at how closely race cars and cyclist follow each others tails to benefit from drafting.

Geese coordinate the way that they flap their wings to maximize the benefits of each others slipstreams. I doubt that planes or helicopters could gain advantage from such subtleties unless they pay close attention to wingtip vortices.

Don't forget the V formation in flight. It helps geese even if they only have one goose to one side of the lead goose, with the rest of the flock angling off to the other side.

https://en.wikipedia.org/wiki/V_formation

Important point is that the second aircraft is not "drafting" You're not getting a tow.

The second aircraft is surfing the wave out to the side of the first. It's similar to the Kelvin wake. visible here https://upload.wikimedia.org/wikiped...-_DSC06962.JPG

And if you're surfing the wave, you're getting free uplift, so power reduces.

At least that's my recollection of discussion with some researchers in the early days of this project

And when the gaggle arrives overhead the destination airports in Europe do they enter the hold?

Or simply land in line abreast?

Formation flying, by people who don't do it regularly, is a good starting point for the various "Air Disaster" shows..... or possibly a Youtube opportunity in the making.

No - they land at their respective airports. From TOD, one peels off to Gatwick, one to London etc having formate for the last few hours saving $$ and fuel.

And Altas - as for formation flying skills - are you allowed to fly above FL290 without and autopilot?

:ugh:

What am amazing concept as long as one lives in suspended reality.
Am amazing theatrical performance as aircraft form different FIR somehow formate.
Kabuki theatre.

Geese fleets, bio-fuel and electric aircraft all provide distraction from the actuality: Technically feasible but practically fanciful.
In the meantime the industry has no plan for transition from hydrocarbon based fuel, no ETS for seven years (and then only international), a low price on carbon and ASK growth rates that will ensure by mid century CO2 emissions from the industry are among the highest on the planet. Consumption of hydrocarbon based fuel continues unabated.

Fortunately, the world can breathe easy, industry lapdog ICAO will be bound to build bigger offices in Montreal and invite dialogue from member states at numerous "conferences" where jet fuel brings delegates to the talk fest.

Nothing to see move along.

https://theicct.org/blog/staff/icao-...re-your-sister

Perfectly suited for say 2xA350s from LHR to SYD and MEL. They depart a minute apart then fly in company for 18 hours, then part ways near TOD. There are not going to be thousands of aircraft from different FIRs suddenly formating to go places. But of course you know that.

Yes, the transition from hydrocarbon is the number one priority, but taking a small step to save ca 10% on fuel on some routes is not a backwards step in the short term. Ignoring environmental benefits, the cost savings alone will be great. The tech is here, the biggest stumbling blocks will be airport slots.

And if they get the slot logistics sorted, and it works out to even a 5% saving on propulsion, that will benefit post hydrocarbon propulsion (whatever form that takes) won't it?

When I was a kid slip streaming on the race track was a big thing but the following car had to be within feet of the leader. The tchnique was to use slip streaming for the first part of the straight to gain a few extra MPH and then pull out and use those MPH to get past. I was astonished recently to learn that Formula 1 cars are now affected by the wake turbulence of a car ahead of the by up to three or four seconds. (They use a lot of aerodynamic down force and in turn create substantial turbulence.)

Did this thread start on April 1st?

Can't be many pilots on this thread - no one is discussing wake separation issues - there are historic and scientifically proven facts that point to the inherent dangers of flying in the wingtip vortices of other aircraft. No, this is a non starter for so many reasons.

In other dated news....Icarus ignores father's advice to fly at "optimum altitude" and plummets from the sky!

You'd have to be a goose to believe this.

If you're a pilot you'd know that wake vortices tend to stay directly behind the wing tips, they don't expand outwards (much).

The plan here is not to fly in the vortex or the wake, much the same way geese don't.

Here's the source info from the public project release at Dubai this week.

https://www.airbus.com/newsroom/pres...rformance.html

Honk

Is this a French plan? Thought so. Next!

If 1000m is the sweet spot, that's not an issue. It will require TCAS reprogramming to acknowledge the 'Buddy' but read the information people,

This isn't slipstreaming, this is wave surfing and vertical separation is already way less than 1000m in the stack. Two planes 1k apart at the same speed would have plenty of time to take avoiding action, first sign of turbulence lead goes one way, vertically and horizontally and 'surfer' goes the other - simples.

Potential savings are huge, especially as we're trending towards longer, point-to-point scheduling.

Acknowledge the argument that airlines are a (large) net CO2 producer, but at the present time, no other commercially viable solution exists, therefore any scheme to reduce CO2 should be received a little more positively.

It sounds like a completely stupid plan to me. Consider this:
Suppose we can find two flights that can be teamed up. They both have to take off from some airfield. What if one of them is delayed by a minute or so? This will create Slot times as accurate as 0855.20 Z. And dedicated taxi routes completely free toward the holding point. Assuming that all goes well with both aircraft when they start up.
What if one of them needs to check te MEL after startup?
What if one needs to sort things out with passengers?
What if one needs to level off because of traffic once airborne?
Etc.
Too many variables. And the trailing aircraft suddenly does not have a leading buddy. But had expected a leader, and has 10%less fuel on board. Now it wont make it to destination.
Too many variables.

I actually think you're overestimating the complexity. See it as a future project in a time where (hopefully) SESAR2020 reforms to EU airspace has taken place: If you can get a direct routing from a London Control exit point, through Maastricht, Rhein, Prague, Bratislava, Hungary, Romania, etc. on your way from LHR to MEL, another aircraft going to DXB, DOH, SYD, MEL, etc will likely get a similar direct routing. If he is 7nm to your right and in front, you might able to get vectors to "link up" with him. If Airbus implements an autopilot function to keep you 1000m behind him and to the side, the lead aircraft can be given WX and Traffic avoidance instructions by ATC as if you were a formation flight. In that case, it might even simplify ATC operations because two aircraft can be treated as one flight.

All it requires is a vaguely similar starting point and the same exit point from the Free Route Airspace.