Airbus Invents Turning By Fuel?
 

I was looking at the New Scientist magazine and saw this. For me, it's nonsense. You'd need to be lucky enough to not run out of fuel before you find a place far away enough to land, needing miles and miles to line up the aircraft. Not forgetting pitching down during a bank, and pitching up upon roll-out. How on earth could such a system be conceived?

PILOTS are trained how to fly their aircraft if an engine or other flight systems fail, but what if they lose control of the steering?

Now Airbus has come up with a way for pilots to fly a plane to the nearest runway in even these extreme circumstances.

In a US patent filed last week, Airbus says damaged aircraft could be controlled by moving fuel quickly between fuel tanks in the wing, fuselage and tail, shifting the centre of gravity to provide rudimentary steering.

This could easily be achieved, Airbus says, by programming flight management software to include fuel-based steering among its emergency options. If the pilot needed to roll to the left, the system would pump fuel to the left wing's tank. To pitch the nose up, fuel could be pumped to the tank in the tail.

Link: Airbus invents steer-by-fuel emergency system - 08 April 2009 - New Scientist

(It's not April fools, like I thought it was).

It's not as farfetched as it sounds. A similar system has been used for trim -- in Concorde for example -- and pilots have used differential engine thrust to steer a plane with no hydraulics. Sure the response isn't going to be quick but when it is all you have you'll try it.

I read this in Flight International I think it was and they said that it could even be used instead of the flight control surfaces during normal operations as it would reduce aerodynamic drag due to sticking bits of aileron and the like into the airstream - and thanks to fly by wire it could be all done using the normal systems.

Whether or not it is implemented, it will certainly take quite some time - interesting idea though!!

FF

I think New Scientist must have got their dates mixed up. The same issue had an article about human echo-location which I am convinced is an April 1st story...

Is cg movement not how one steers a hang glider?

Patent??
 

That's how for God's sake ORVILLE maneuvered.

PRIOR ART!!!!!

And the fundamental principles of flight have been in place for how long ? Not to mention the millions (billions) of [insert favourite currency] that have been pumped into aerodynamic R&D over the same period of time !

If such a fundamental change were possible, it would have happened by now ! Sure as a trim / emergency / whatever thing .... but for everyday use, I'll keep my ailerons thanks ! For those doubters .... one word .... BA38.


When were you last on a longhaul flight as pax Cosmos2 ? :cool:

I saw this guy on a news show who did echo-location. Unless they were lying about his blindness, I'm not sure how he could fly down a city street on a skate board. Yes the US Navy was interested.

I looked him up: Ben Underwood. There's also a wiki article.

Moving fuel would have to be done extremely quickly and in the right amounts for sufficient effect. The issue is the fugoids that inevitably emerge in any aircraft without the use of flight controls, especially swept wing configurations. Most Airbus pilots have done the "complete loss of hydraulics" drill and had to land the simulator using engine and mechanical horizontal stab trim alone. I spoke with someone at Airbus (former FAA) and he said he'd done it in the airplane and it wasn't that hard, (although the landing was, he said). We practised it in the 330/340 but not to the landing. The Sioux City DC10 crew had a very difficult time with the fugoid oscillations and learned quite quickly how much lead/lag they needed in terms of engine thrust. The whole point is, one must do exactly that...lead and lag the controlling inputs. If it's too early, too much, too late or not enough, the fugoids slowly become unstable and loss of control will eventually result. With computer control and such factors built-into the algorithms, it may work but shifting fuel manually to control the airplane would be, I think, damn near impossible to accomplish and execute to a safe landing. I call April Fool, but the idea may only be ahead of it's time and the joke will be on us!

Is it any nuttier than landing an a/c without any flight controls?

THAT has saved a big Scarebus out in Iraq (or similar- no loss of life).

And The guys who lived through the Sioux City crash
NASA came up with a scheme (widely shown on TV) where 'NO CONTOL' landings in a MD-11 became routine.

Trust Airbus to come up with their own 'FBW' version of it!:8

Kind of, but because the wing is flexible it's more to do with altering wing loading and "billow shift" than actual C of G. :ok:

PJ2;

Do you mean phugoid?
In the DC-10 SIM it is controllable to a landing. And it is a very realistic SIM.

In the DC-10 SIM it is controllable to a landing.

(a) I don't think that we are fussed too much as to how anyone might wish to spell things ..

(b) sim fidelity will be very much a case of how the box is modelled, set up, and tweaked

(c) Al Haynes made no secret of the fact that the boys didn't have much of an idea of what was going on in the beginning .. without knowing the jargon, they figured out how to get some control over the phugoid

(d) if it hadn't been for the phugoid oscillation's catching them coming in over the fence .. they might have just got away with a landing rather than rolling themselves into a ball. As Haynes observed in the Dryden presentation -

We were starting a down phugoid, and starting a right bank, 300' in the air. And we just, that's where our luck ran out.

An intelligent directional and vertical profile flight control mechanism using differential thrust was officially in the works after a famous accident involving loss of hydrualics (not Sioux City incidently). FAA ran trials and this system was tested successfully, however it all got brushed under the carpet after the true cost came to light.

This would be a far better bet than moving fuel around IMO.

I have tried several times in the A320 SIM, to fly overhead the airport at 10.000`/ speed 250 kts and then remove all hydraulic power (= no flightcontrols and no stab trim)

It is a very good learning experience and a "confidient builder" to see that the aircraft is quite easy to control and steer only using asymmetric engine thrust. The trick to learn is the lead/lack of thrust.

On the first try, I landed the aircraft on the center of the runway, and one dot low on the localizer. Quite hard landing though, but suviveable. Try it next time you have time to spare in the sim.

It would though be a very scary thing to do real life, and it reminds me that e.g. Sioux City and Bagdad A300 "No flight controls landing" both were MUCH MUCH more of an extraordinary performance when compared to the Hudson River landing, which I think most 40 hour PPL could have pulled of just as good.

Greetings
PJ2 Phugoids are oscillations, most like to occur around 15 17 deg pitch, so I dont see the point related to turning with fuel :}

Entirely feasable idea.

I like it.

We used to have lots of fun on the nimrod getting the back end crew to all run to the front or the back together while new FO's were hand flying close to max height to weight.

kijangnim;
First, the assumption here is loss-of-all-flight-controls, usually due to loss of all hydraulics. I can't really conceive of a situation where control in pitch is available but not in roll. And if that's the case there are other, perhaps less elegant or at least imaginative ways of turning an airplane - a small, momentary deflection of rudder (same amount as yaw-damping, roughly), particularly in a swept-wing aircraft, will do nicely.

Next, I understand your point and phugoid oscillations quite clearly. The point was made in the first post by the thread-starter - turning affects pitch; this is also acknowledged in the NS article. It was this problem, not turning, (by whatever means), that I was considering. This is precisely the problem that Sioux City illustrated. All pilots know that turning will cause the nose to drop - my thought was, how is that to be controlled through fuel movement? The article mentions pumping fuel to and from the tail. Obviously not at present rate capabilities!

I don't think it's that simple, having flown the sim using only stab trim and engines. While such a fuel transfer system is common in transport aircraft, it would have to be done with a great deal of flexibility in terms of rate, timing and amount, and, I submit, it would have to be computer-controlled but those are details - it is the idea I'm interested in. I am assuming by your comments that you know phugoid oscillations can destabilize if one is not careful with the airplane. Despite what some say about it being a piece of cake, the success rate is not stellar. It was to the notion of how to keep it stable that I was directing my comments. Clearly there are other issues such as design, testing, manufacture, certification, maintenance which are yet to be addressed.

Greetings,
I see your point, and what I know about phugoid oscillation, is that it takes place at high pitch angle (during windshear recovery for example) and to give an image, it is as if the airplane was suspended to a huge spring, the oscillation will induce unwanted load factors.
As you said technology is easy to visualize, but dam hard to implement, how ever the idea is great, and needs to be investigated in depth :ok:

As deltayankee already said, the basic notion is at least 40 years old - see Concorde, where it was used to minimise trim drag when the CofL moves aft significantly during the transition from subsonic to supersonic.

Do subsonic airliners have fwd and aft (tail) trim tanks?
Can existing fuel pumps move fuel fast enough to obtain any kind of long and lat control? (IIRC a typical fuel pump moves about 2t/min.)

If the answer to either question is 'no', I would suggest the idea is stillborn: nobody is going to carry the additional weight of tanks, pipes, and beefed-up pumps, for a one-in-a-million + occurrence, i.e., totally loss of any other form of control.

CJ