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Comment by scotty79 | Hacker News Reader

Absolutely horrified.

> The Cobalt’s engine shut off and the lights inside and outside the car dimmed. Melton hit the brakes, but no power from the engine meant no anti-lock brakes and no power steering.

I wasn't aware that anti-lock brakes (is that ABS?) is not a purely mechanical system. Also, was power steering hydraulic or electric? Shouldn't it be run of battery for short period of time?

> While Brooke’s lap belt glued her waist to the seat, her shoulder harness went slack the instant the engine shut off.

Now that's just criminally stupid.

EDIT: I guess I need to read through to the end to the article but that's a hard read for me for some reason.

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That's not quite right. The Cobalt, like a lot of cars, has a seat-belt pre-tensioner. This is an explosive device that pulls in the seat belt by about 4 inches when the air bags fire. The seat belt's basic inertial locking function still works without power.

Anti-lock brakes, on the other hand, definitely require power. They're computer-controlled, using pulse counters in the wheels, electrically-controlled brake valves, and rate gyros. With ABS, jamming on the brakes is just fine. Without ABS, jamming on the brakes is awful. In the first crash mentioned, the driver not only jammed on the brakes, but having entered the skid, turned away from the skid, which makes it worse. It was also a side crash, so the air bags would not have fired. Who practices non-ABS skid recoveries in cars any more?

Losing electrical power in that car is a big deal. You lose propulsion, power steering, power brakes, anti-skid braking, seat belt pre-tensioning, and air bags all at once. That's bad design. All those electrical functions should be enabled until the transmission is in PARK.

And the airbags wouldn't go off, either, without the key turned on.

But having your car suddenly go from having abs -- where jamming the pedal down is probably the right thing to do -- to a state where the driver must pump the pedal is probably more than virtually all drivers can handle.

Given my experiences i personally feel she has shown terrible lack of skill - why slam on the brakes? The car was fully controllable. I`ve had my engine stall once and i mistakenly turned my engine off (and the hydraulic power steering went off) midturn and it wasn't a light car. I was completely fine.

On the other hand i find american buisness practices despicable and sickening.

> why slam on the brakes?

Maybe she wanted to stop the car she had lost control of?

The reason for ABS to exist is that slamming the brakes is a very natural thing for (most of) us to do in a dangerous situation. If you're designing a car for a human to drive, you should keep this in mind.

I once had a sheet of plastic blow on to my windshield at 70 mph on the Houston Beltway effectively blinding me. It takes significant presence of mind not to do something dumb.

To amplify that observation: ABS was banned from Formula 1 because it made braking too easy. Modern ABS can outperform people who are paid in excess of $40 million/year to be the best drivers in the world, who have unreal reflexes, complete mastery of a vehicle, and the ability to make good decisions under high-pressure driving situations.

The idea the average driver is an adequate substitute for ABS is laughable.

Consider the possibility that this person may never have driven a vehicle without ABS. There would likely be little or no emphasis for teaching a skill (pumping the brakes) for a person in driver education, after a generation had passed with reliable ABS equipped on every car. Also consider that even a person with the requisite knowledge, driving a car with ABS, may not realize their situation until after they are in a skid.

Losing power steering in a vehicle with hydraulic "power assist" steering may be completely unlike losing power in a vehicle with electric assist. Given that in the recall, GM is replacing the electric power steering assist motor, one might assume that it becomes much harder to steer after loss of power. In other words, it may be much easier to rotate an unpowered hydraulic motor by its output shaft than it is to rotate a gear-reduction electric motor by its output shaft.

Finally, the fact that someone (such as yourself), or even that many people may have been skilled enough to be able to avoid fatally crashing their Chevy Cobalts is not proof that the cars are safe (enough). Nor does it excuse GM from ensuring that their products meet mandated safety standards.

She had scant seconds, the Air France 447 pilots had over a minute[1]. People do not function correctly in situations for which they are not trained - eg automation failing.

http://en.wikipedia.org/wiki/Air_France_Flight_447

That's a very good comparison. (The Wikipedia article on this isn't very good, though.) The Airbus flight control system (not the autopilot) in "Normal law" mode will prevent stalls, and it's normal procedure to pull the stick all the way back if you want the nose up. The control system will keep the control surfaces just below the stall point.

Flight 447 had clogged air speed sensors. The flight control system detected this and dropped to "Alternate law", which does not have stall protection. In "alternate law" mode, pulling the stick all the way back will, as in most aircraft, cause a stall. This drastic change in flight control confused the pilots. This despite them having been trained for a drop to alternate law.

Airbus has redundant air data sensors, but not, apparently, with enough redundancy.

I'm not sure why you've been downvoted. She obviously lacked driving skill. When a vehicle loses power you don't slam on the brakes. Losing power is not a panic situation, especially on a long straight road. You either coast to a stop or gently slow down.

You're both getting downvoted because you're coming off as both obtuse and heartless.

When things go wrong at 60mph, people panic. When you're panicking, it's hard to remember skills you were taught in calmer circumstances--and nobody practices high-speed power failures, so you don't even have muscle memory to fall back on.

It is an engineer's responsibility to prevent dangerous situations from occurring, as far as is practical. "Dangerous situations" include those which are likely to induce panic in an average driver, even if a particularly skilled driver could handle them. Often it isn't practical, which is why so many people die in traffic accidents every day, but in this case the problem with the ignition switch was known and deliberately ignored. There's no excuse.

> in the first crash mentioned, the driver not only jammed on the brakes, but having entered the skid, turned away from the skid, which makes it worse.

I agree that jamming on the brakes was bad. But according to the article the back end "fishtailed, coming up on her left" (meaning her front end drifted right). So, turning the wheel counterclockwise (i.e., to the left) was the correct move, although it's also possible she over-corrected, hard to say from the article.

ABS is indeed the Anti-lock Braking System and I think it depends on sensors to determine the skidding amount and on software to determine the interval at which the brakes are applied and let go. So, the ABS is run off electricity and not a purely mechanical system. However, brakes themselves (without the "anti-lock" part) are purely mechanical/hydraulic, but since the brakes locked up, it didn't matter.

I'm not entirely sure about electric power steering systems and how they work.

ABS: https://en.wikipedia.org/wiki/Anti-lock_braking_system

EPS: http://www.caranddriver.com/features/electric-vs-hydraulic-s...

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

ABS depends on power not only for wheel speed measurement, but also for power to drive the brake piston.

> I'm not entirely sure about electric power steering systems and how they work.

It comes in a variety of forms, but it's usually an electric motor that adds torque as you turn the steering wheel to make it easier to turn.

In a hydraulic power steering system, if the power is cut, the driver can still turn the wheel (although it's much harder to do). In an EPS, is this still true?

> Also, was power steering hydraulic or electric? Shouldn't it be run of battery for short period of time?

Further down the article it answers this; yes, if the engine had simply "died" the power steering would still have run off the battery. But because the ignition was turned off, all the power was cut off.

Cutting all the power based on only the key must be the most stupid thing I've heard today, especially power steering?! Really, I've worked in automotive and all designs I've seen keep important components alive as long as the vehicle is moving, regardless of key position. THAT is the design flaw here, not that the key is too easy to twist.

This can be quite a hot topic, I frequently see people wanting the key as a "last line of defense against electronics and programming error switch" and i can understand that concern and sometimes think that way myself but really, if they are not confident enough in their system and think they require a human controllable "main switch" they might as well put a big red emergency shutdown button in the middle of the dashboard, i wonder how many people would buy such a car.

The point is key switches as cut offs work fine when the component doesn't have major faults.

Any other electrical control system could cause just as many issues if designed poorly. Imagine if GM was just as sloppy with a push-to-start electronically controlled system that could shutdown due to EMF.

And there have actually been issues with push-to-start systems. One model I can remember required the user to hold down the button to shut off power in an emergency, when the most common user reaction was to rapidly jab the button.

>The point is key switches as cut offs work fine when the component doesn't have major faults.

GP is correct. Cutting the electrical power to the power steering assist while the car is in motion is a design flaw. Can you think of any reason why the car should not have operational power steering when it is in motion[1]?

[1] If you thought "for towing", that situation can be handled by the tow truck operator manually disabling the steering.

>Can you think of any reason why the car should not have operational power steering when it is in motion[1]?

You can't have an electrical cut-out that doesn't cut-out certain components. The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay). If the ignition switch is not used for that purpose they would need to put a big red button on the dash like GP said.

The ignition switch cutting all power has worked without incident in every other brand for many decades. The issue here is GM's incompetence, and I'm not inclined to the idea that they would have competently implemented another system.

If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).

>You can't have an electrical cut-out that doesn't cut-out certain components.

Nonsense. Even the old mechanical ignition switch simply engages a number of relays and other electrical/electronic controls.

>The reason you need a complete electrical cut-out is for safety reasons (eg fuel leaks into engine bay).

Fuel cutoff relays exist and have been in use since, not long after electric fuel pumps were put into use.

>The ignition switch cutting all power has worked without incident in every other brand for many decades.

In no way is that statement predictive of the efficacy of such a simple scheme going forward with more advanced electronic controls.

>The issue here is GM's incompetence,

No arguments there.

>If anything I think this is an argument that power steering should be limited so that average drivers don't lose control of their vehicles if it fails (I've lost power steering in motion due to an engine stall, it is very scary).

It is limited. It's more properly called power assist. It shouldn't be scary. Power steering is most useful only at low speeds.

What's the chance that:

1. You get a fuel leak in the engine bay while driving. 2. There is not already another safety system detecting this. 3. The driver actually notices this while driving. 4. The driver decides to take action by turning off the key, without stopping the car first?! 5. For the scenario to be dangerous we are also assuming this leak is severe enough to eventually cause ignition and catch fire.

This is like taken from a b-grade action movie and doesn't happen. Any scenario i can think of where you would require an emergency shutdown you would also want to get the hell out of the car asap. You could also imagine that things like cruise control "get jammed" but i find that extremely unlikely since software doesn't have the same wear and tear as mechanical components and sensors. Worst worse case you can always stop the car use the mechanical brakes or gearbox since those have more power than the engine. Unless we are talking about brake by wire or similar but those have _completetely_ different safety standards, there is also a reason those are not on the market yet.

GM failed to perform an adequate hazard analysis. Faultiness is inherent in any vehicle driven for a number of years, and as we've seen a single fault can disable many safety-critical features like ABS or Power Steering.

The potential impacts of the failure modes of the key switch are quite severe, although in normal use the likelihood of any one is low. Because of the severity, some risk mitigation should have been in order regardless of whether the component "works fine" or not.

I'm fine with that. I just think people are throwing out the baby with the bathwater by declaring mechanical ignition switches to be the problem (when they have worked fine for decades in every other brand).

There are also mechanical solutions to this, old Saab cars for example required the gear to be in reverse before you can remove the key.

If you cut engine power hydraulic steering is basically dead, as are the brakes. The power assist on brakes usually uses engine vacuum and power steering is mostly driven by a hydraulic pump running off the motor. I'm not sure about the newer electric steering models.

But for most cars, simply having a stalled engine makes them nearly undriveable due to the weight of the controls.

I think that driver training should start with unassisted cars - no abs, power steering, power brakes and no stability control. And that early training should include skid control.

Once competency in those areas is gained, then move to bugger cars with power systems and electronics.

I'll always be grateful for learning to drive in a completely manual car with no power assist on anything. It means I can always tell when the car is doing something for me. I still drive an older car for fun which is completely 'analog'. It's mic more rewarding to make good progress by using skill rather than silicon.

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