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My first ever car was a Standard 10 (1957 model with "Standrive" 2-pedal control - just accelerator and brake) and it did have a clutch but it was normally disconnected by springs at tick-over and it engaged using centrifugal weights to force the clutch to engage as the engine speed increased. It had a electric switch on the gear lever so that it used engine vacuum to force the clutch to disengage as I held the knob to change gear. It was a clever fully manual automatic approach to driving. Luxury cars of a similar vintage had a pre-selector gearbox and fluid flywheel arrangement which was also a clutchless arrangement with manual gear selection. The answers to zero to above tick-over starting in a manual gearbox ICE without the driver using a clutch pedal are about 70 years old, though nobody uses them any more.

Away from cars but continuing the assumption that the programmer knows better than the driver what is best, I remember a plane crash at a air show. The pilot in a latest model of an aircraft was demonstrating what it could do, and did a manoeuvre close to the ground then went for full power to get height to clear the trees he was heading towards. The plane's software reduced the engine power in the interests of fuel economy and the plane hit the trees. One scene of wrecked plane, dead pilot and spilled fuel all because the plane manufacturer had given the programmer's decision priority over the pilot's requirement.

Hmmm, sounds like an urban legend. Can you recall when or where this is supposed to have occurred? It should be possible to find the original accident report online.

Tim

IIRC it was an early Airbus of some sort. TOGA power was restricted in spoolup or something. I cant recall more than that.

Nothing to do with fuel economy though - they were intentionally operating the aircraft below its stall speed in order to demonstrate the computer protection. In this case the pilot pulled up which would have caused a stall - the computer prevented that, but there was not enough time for the engines to spool up to give climb thrust before they ran into the trees. Had the computer not been active they would have stalled and fallen onto the trees anyway.

The Airbus stall protection has saved a great number of lives, including the 'Miracle on the Hudson'.

Theo

Possibly this one?

That's what I recall, yes. No idea if it is that to which Tim+ refers...

I am remembering a short news report broadcast many years ago so I know it was a real crash, I just don't remember when. I did a search for "air show crashes" and was offered an enormous list of them, each with a thumbnail description. After nearly 2 hours of ploughing through the list I found one that sort of meets the broadcast description of the crash. At least it is sufficient to lift it out of the Urban Legend category.

Looking at the history of the A320, it was the first Fly-By-Wire passenger aircraft so it did rely on software interpreting the pilot's intentions as signalled by the controls. The first A320 was delivered to Air France on 28 March 1988 and began commercial service on 8 April

Jim

So that's the Air France flight mentioned upthread:

Pilots regularly perform takeoffs are less than maximum thrust, for fuel consumption and noise reasons, but that is a calculated figure based on the conditions. The full thrust is always available to them if required.

In this case the pilot had deliberately set the throttle *way too low* for demonstration purposes. If you watch the crash footage:

The pilot noticed they were approaching the trees and commanded thrust. At about 0:17 you can hear the engines start to spool up, but that takes about

The pilot said they commanded takeoff thrust and nothing happened. But jet engines are big heavy spinning things and changes take time to happen. There wasn't enough time here. Perhaps time seemed longer in a panic scenario?

In other situations, if GPWS gives you a TERRAIN, TERRAIN, PULL UP! alert the 'terrain escape manouevre' is to apply maximum thrust and pull up, but you have to understand that pulling up is only going to be allowed within the flight envelope which depends on your current airspeed. If you don't have airspeed, pulling up too much would cause a stall and you'd fall out of the sky - the last thing you want when you are close to the ground.

Theo

At least one Bristol Blenheim was written off recently by ramming the throttles open to get full air but then starving the engines of fuel.

I d In modern aircraft, ============ Full Authority Digital Engine Control (FADEC) system acts as an intermediary between the pilot and the engine.

Computer-Managed Acceleration: Even if you "slam" the throttle forward, the FADEC ignores the instantaneous command and instead calculates the maximum safe rate of fuel increase.

Protection Systems: The computer monitors dozens of parameters (like air density, engine temperatures, and RPM) to ensure the engine accelerates without overheating or stalling.

Spool-Up Delay: You will experience a "lag" or spool-up time (typically a few seconds) because the physical mass of the engine's internal rotors must gain inertia before producing full thrust.

Older Jet Engines (Hydromechanical) ======================= Older engines relied on mechanical linkages and simple fuel control units (FCU). Suddenly calling for full throttle on these systems could be dangerous:

Compressor Stall and Surge: If fuel is added faster than the compressor can provide air, the combustion chamber pressure can exceed the compressor's output pressure. This causes airflow to reverse, often accompanied by loud bangs, flames from the intake or exhaust, and severe vibration.

Overheating (High EGT): Excessive fuel without immediate airflow causes a rapid spike in Exhaust Gas Temperature (EGT). This can melt turbine blades or cause catastrophic engine failure within seconds.

Flameout: Paradoxically, a "rich blow-out" can occur where the sheer volume of fuel displaces oxygen and extinguishes the flame entirely. "

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It is possible that this was the first time the pilot used a FADEC under emergency conditions.

Nothing happens. Or rather, nothing bad happens. Anything with a high bypass turbofan (post-1960s) will have electronic control, and that will make sure the engine is operating within safe parameters. If you ask for maximum thrust it'll give what it can, but not what it can't.

Just like flooring it in a modern car won't cause the engine to die through an over-rich mixture - the accelerator pedal is just an input to the ECU and the ECU won't let you command unsafe mixtures.

Theo

And in older cars it might not cause the engine to die.

If the throttle plate is jammed open then theres no chance of an over-rich mixture

Unless there have been changes since build, the camshaft progressively switches out sections of a series resistor bank, coupled with also switching the 4 motors on a vehicle from "four in series" to "two in series, two in parallel". No solid state equipment is involved.

Somewhere in the loft I have some of the calculations I did when designing the similar equipment for the now retired BR Class 313. That, although able to operate from AC or DC supplies, still used a camshaft and resistor for the actual control.

Chris

Horses for courses. My partner's Nissan Leaf has all the performance I will ever need or desire.

Chris

I love my Leaf too!

And in the end that is the key takeway. You trade a bit of efficiency and top speed for lower cost.

An electric motor does not deliver full power at low speed. If that is acceptable, fair enough

Right. It's constant pumping of the accelerator pedal which causes flooding. I seem to remember that the easiest way to deal with a flooded engine is to push the pedal right down and hold it there while turning the engine over with the starter motor. This eventually clears the cylinders of petrol and dries the spark plugs, allowing the engine to fire.

I'd have thought that with the exhaust system full of a petrol/air mixture there could be a fair chance of a "backfire" when the hot exhaust meets the mixture. I've never experienced it, though. Has anyone?

It's only on some types of carburretor that pumping the accelerator pedal causes flooding.

Thanks for the information and for finding the video. I didn't know it existed.

I was remembering the news as described on the radio and I had no way of deciding what was fact and what was opinion. I was also aware that the crashed plane was one of the very first deliveries of that first ever fly-by-wire arrangement, and as a former programmer I know that it is virtually impossible to prove the absence of any remaining bugs. Sod's Law guarantees that at some time a real life experience will be something the test data didn't check for. So it is possible that the crash caused an urgent review of the software before the next delivery was made. In a business where customer confidence controls the level of orders, any software update because of the crash would have been a closely guarded secret. Pilot error of reacting too late is much more forgivable as a reason for the crash than a software bug would be.

SU carburettors don't have an accelerator pump, I don't know about Stromberg CD types. Pretty much all downdraught types do.

Another way: I had a Rover 400 series for a while (rebadged Honda Concerto type, not the genuine BL one) and very short journeys such as kerb to driveway with a cold engine tended to flood the cylinders. In the old days, leaving a choke too far out for too long (remember the handbag storage hook?) would also do it.