Human-Centred Design

[kellykelpie]

I'm interested in what pilots of new technology aircraft think about the human factors issues of automation of such aircraft.
Is there too much automation, or is there not enough? Are the systems no longer transparent to the pilot. Examples would be appreciated. It is for a Uni assignment.

[Nozzles]

My immediate observation is that pilots are gradually being further and further removed from the physics of what happens to the aircraft when the pilot demands something of it. In flight control systems, for example, we progressed from mechanical linkages, where all the feedback you felt was real, through hydraulic systems where artificial feel was added. Then came aerodynamically stable (just) airframes that were fly-by-wire controlled. The current situation in the fighter world is that the latest machines are naturally unstable and human pilots are unable to control them in simple level flight. Thus, the pilot puts in a familiar control input to achieve a certain manoeuvre, but has no idea what the flight control surfaces are doing to achieve that manoeuvre. It makes emergency failure diagnosis more difficult because there is no logical link between input and effect. Additionally, as designers are finding new and unconventional ways of manoeuvering aircraft (e.g. 3-D engine exhaust nozzles, flexing wings etc.) the water will become even more muddied. However, I think that the whole concept is something we simply need to get used to. It is the future, but people (especially as they get older) are less inclined to embrace new concepts. As an ex-Harrier pilot I once flew a simulator that was a development platform for future VSTOL concepts. They wanted to take the nozzle lever out of the cockpit, and make the aircraft controllable with only two 'inceptors'. In a Harrier, if you want to do a vertical take-off, you move the nozzle lever so the nozzles point vertically down, select full power with the throttle then control pitch, roll and yaw with the stick and rudder. In the two inceptor concept, you pulled back on the right-hand inceptor (where the stick normally lives) whilst on the ground with the engine idling. The system said "he must want to go up", so it rotated the nozzles to the vertical and spooled up the engine. Once in the hover, letting go of the stick meant the thing would hold altitute. You could not pitch the aircraft-pushing the RHI forward would simply spool the engine down because the system thought you wanted to go down. If you pushed the left-hand inceptor (where the throttle normally lives) forward, the system realised you wanted forward speed, so it would power up the engine slightly and slowly rotate the nozzles aft. Once the wings were developing enough lift in forward flight, the system would rapidly pull back the power on the engine-extremely disconcerting as your 'throttle' was still parked at max! We figured that a kid who was good with video games but had never flown a flight simulator would pick it up quicker than us, as he/she would lack the preconceptions that we had about what should be happening. And I think that's the answer-the new generation will have a lot less problems accepting these systems than those of us discussing the issue!
Hope this helps with the assignment-if you need more, let me know.

[kellykelpie]

Thanks Nozzles for a very interesting post.
I definately agree that the new generation will take to this new technology like a duck to water. This brings up an interesting point about having senior pilots being used in the design process.
I think we are still being constrained by past designs and believe in a ground up - totally revolutionary concept for new flight decks.
The Harrier is certainly a good example of how a revolutionary concept can flourish. They must have been great to fly too.
Regards Kelpie.

[Sheep Guts]

Very good reply Nozzles.

The new technology today is suppose to give feedback to the Pilot of what he or she is doing , and so it should. But parts of the new flyby wire design have a few loop holes, that their predecessors can handle alot better.

One of them comes to mind, after an occurence when a 767 ran out of fuel over North America. Gashtly as it sounds this story has a happy ending. The Pilot ran out oi fuel and in short glided the Aircraft to land on a smaller Aerdrome called "Gimly Filed". In doing so, the Pilot had to side Slip the Aircraft to get into the small airstrip. Which he did with no problems. He was an accomplished Glider in his off time. The 767 is not a Flyby wire Aircraft, and hence it responded normally to such unormal control inputs.

This puts the question, can a flyby wire Aircraft perform similarly with these type of inputs. I have asked a few Pilots now of Aibuses and alike about this, and they all say that the control inputs would be read as cross control inputs and not respond. If this is the case,( I stand to be corrected) then one would think that these Aircraft in such unusual flight configerations would suffer. My criticism not only comes from this incident, but many other incidents and accidents. The St Louis DC-10 where the No2. Engine failed and all of the Hydraulic lines were severed. Resulting in the Crew members juggling power levers to accomplish a crash landing and saving half the passengers. If this occurred in a FlyBy wire Aircraft what then?
By the way, the St Louis accident scenario was practised with 100 odd crews in a sim, and they all crashed.

Then a positive from this. When I was a Tech in the RAAF in Tindal Australia. Our 75SQN CO at the time persihed in a Hornet "God Rest His Soul". It was the resultant of a Midair Collision. The other Aircraft another Hornet had nearly half of its wing clipped off in the collision. The onboard systems compensated for the loss of control and the Pilot managed to Return to Base with problem. This shows that Flybywire systems can be inherently safer aswell.

Our removal from the basics and consequences of our actions in controling a Large Jet, through Flyby wire systems has both pros and cons. The pros being the New Generation Pilots with their Computer Simulator skills would definitely adapt to these new technologies, and cons being, would they be able to cope with complications arising lack of practical experience.

Hey maybe Im just bantering

Regards
sheep

[kellykelpie]

Great reply Sheep,
I am very interested in hearing from airbus pilots regarding what would happen in the emergencies talked about by Sheep Guts.
Anyone?