Please create an account to participate in the Slashdot moderation system


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


Comment: Re: Larger landing area (Score 5, Interesting) 340

Certainly looked that way to me. On the last oscillation before touchdown, with the tail end moving towards the left, the thrusters keep pointing the same way as the rocket goes through vertical and only change direction a little bit afterwards. This increased the amplitude of the oscillation rather than decreasing it. The thrusters should have changed direction before passing through vertical, not afterwards. I can't imagine them getting this wrong in software, it's basic dynamic stability 101, so a sticky valve seems likely.

The rocket ended up landing almost perfectly vertical, but still rotating so the base was traveling sideways over the landing pad. No way they could stay upright like that.

Comment: Re:Not 'close' (Score 1) 340

Actually, I think #3 was there, but #4, zero rotation speed (the derivative of #3) was not. It touched down pretty much vertically, but still rotating. Just before touchdown, the rocket seemed to become dynamically unstable because the rocket exhausts moved with a bit of lag. They keep firing in the same direction while the rocket passes throug vertical and in the other direction, and only then start correcting in the other direction. They should actually have changed direction before the rocket was vertical so the rocket would not just return to vertical, but stop rotating as it reaches vertical.

Comment: Re:Perfect security (Score 1) 460

by michelcolman (#49425039) Attached to: Planes Without Pilots

It is easy to quantify. And the quantification is "4/5ths of commercial airplane accidents are caused by humans doing the wrong thing".

Yes, like he said, it's tragically easy to quantify the latter. But what about the former, how many accidents are prevented by having a pilot on board? That's not such an easily available statistic but trust me, it's a lot higher. I've prevented my fair share of accidents (just doing my job like any other pilot, it's what we're trained to do) but haven't caused a single one.

Comment: Re:Sensors wrong (Score 1) 460

by michelcolman (#49421851) Attached to: Planes Without Pilots

Air France 447 was one of those incidents.

But who's to say a remote pilot would have done any worse? Everyone died on that flight, so how much worse could the remote pilot have done? Air France 447 isn't the only crash to take place because of clogged pitot tubes. There was also Birgenair 301 and a couple others.

There's also a list of flights where the exact same failure occurred, but the pilots handled the situation correctly and landed safely. I don't know what a remote pilot would have done, but it's certainly easier when you are actually on board so you can look outside or at least just feel the motion of the airplane. And as for automation, well, it would have crashed every time.

Comment: Re:Sensors wrong (Score 5, Insightful) 460

by michelcolman (#49421799) Attached to: Planes Without Pilots

80% of accidents may be due to pilot error, but probably close to 99% of all would-be crashes due system failures do not turn into an accident because of pilot intervention, and therefore never make it into the accident statistics. Take the pilots out, and you'll see at least an order of magnitude more crashes unless technology improves drastically.

I'm a pilot, I've never had a crash (like the vast majority of pilots), but I've had several situations where automation failed (either completely shutting off or doing something unexpected and dangerous) and a crash would have resulted if we hadn't taken over.

In fact, there are lots of crashes that are attributed to pilot error not because the pilots were the only cause for the accident, but because some system failure occurred that should have been handled safely by a well-trained pilot and somehow wasn't. We are expected to handle these problems, so if we don't, it's our fault (and rightly so).

Take Air France 447 for example, airspeed sensors iced up, autopilot disconnected, other flight crews in the past had had the same problem but handled it well, these pilots got confused and crashed. Probably goes into the statistics as pilot error, but without pilots the plane would have crashed anyway. Every time, including on those flights where the crew did handle the situation correctly (even with inadequate procedures for this particular failure at the time) and landed safely.

Another example, the Turkish Airlines flight that crashed short of the runway in Amsterdam. The plane was flying on autopilot, yet it's "pilot error" because the pilots should have immediately reacted when the autothrottles pulled the throttles back to idle and the airspeed decayed rapidly. Caused by a malfunctioning radio altimeter which let the automation think the plane was low above the runway and it was therefore safe to pull the throttles back for touchdown. There's a reason why we have an initial training and a yearly recurrent training for automatic landings. Haven't had the training? Manual landings only.

So no, automation is not safer than human pilots. Not by a long shot, at least not yet. And given the slow pace of technological advancement in aviation, it will be a very long time before it will be.

Take military drones, for example. Their mission is not exactly complicated: in relatively nice weather, take off, fly a predetermined route, drop some bombs, fly back and land. There aren't nearly as many drones as airliners flying around, yet drones crashes happen all the time, it's not even news.

Comment: Re: Too many pixels = slooooooow (Score 1) 263

by michelcolman (#49420879) Attached to: LG Accidentally Leaks Apple iMac 8K Is Coming Later This Year

They really ought to switch to floating point: one float per color component per pixel. That's 24 bits plus 7 bits of exponent (not using the sign bit). Would also get rid of the problem where the average between two colors isn't really the perceptual average. Thanks to the separate exponent, floating point has such a wide range that it could correspond to our actual perception of color, and basic mixing operations would look a lot better.

Comment: Re:Trademark (Score 1) 111

by michelcolman (#49412931) Attached to: Swiss Launch of Apple Watch Hit By Patent Issue

Given that they are not exactly in the same market, (Leonard Timepiece produce luxury timepieces, Apple produces electronics) the risk of confusion is low anyway and probably they won't give a fuck about it.

It's a different category of product. The trademark was registered for "timepieces and components of timepieces"

So you're saying that the Apple... errr... "Watch" is not a timepiece and therefore no confusion is possible?

Comment: Re:As long as it's not windy (Score 1) 140

by michelcolman (#49386641) Attached to: World's Largest Aircraft Seeks Investors To Begin Operation

If an airship can fly at 80 kts (which is very fast indeed for an airship), it will *not* require 100% more power to increase its speed by 5 kts. That's just preposterous. Drag probably increases with the square of the speed just like (roughly) for airplanes. Obviosuly an airship will have more drag at any speed because of its huge frontal area, but the shape of the drag curve will not be drastically different. Certainly not to the point of requiring twice as much power for 5% more speed.

So the comparison with a small plane that has a cruising speed of 80 kts is in fact perfectly valid.

Comment: Re:As long as it's not windy (Score 1) 140

by michelcolman (#49384941) Attached to: World's Largest Aircraft Seeks Investors To Begin Operation

The GGP was talking about making headway against a strong headwind. In a steady headwind, any airplane with an 80 kt cruising speed will see the same effect from that headwind. The fact that the airship happens to be really big does not change the fact that it simply gets the same wind speed vector added to its airspeed.

Gusts would just make the flight more turbulent, but would not change the average speed much.

Comment: Re:Nintendo "Corporate Social Responsibility": (Score 1) 100

by michelcolman (#49384533) Attached to: Mario 64 Remake Receives a DMCA Complaint From Nintendo

There are legal reasons requiring companies to react to violations of their copyright and trademarks, since they may otherwise legally lose them. However, they could have just reacted with "place a notice on your website that we own all the trademarks and copyrights but gave you explicit permission to keep this excellent remake on your website as long as it's limited to part of the first level."

It's more publicity for their game and may actually lead to more sales from people trying out the web version and then buying the real thing. But alas, lawyers don't think that way.

"I am, therefore I am." -- Akira