A typo that almost crashed a plane | Hacker News Reader

A typo that almost crashed a plane

sfchronicle.com

32 pointsdanso27 comments

Tangentially related: In 1988, Iran Air flight 655 was shot down by an American missile cruiser, killing 290 people. It was likely due to a UI problem with the aircraft tracking system on the cruiser that reused an ID number from a potential enemy fighter aircraft. https://en.wikipedia.org/wiki/Iran_Air_Flight_655

> The Aegis System software reuses tracking numbers in its display, constituting a user interface design flaw. The Aegis software initially assigned on-screen identifier TN4474 to Flight 655. Then just seconds before the Vincennes fired, the Aegis software switched the Flight 655 tracking number to TN4131 and recycled Flight 655's old tracking number of TN4474 to label a fighter jet 110 miles away. When the captain asked for a status on TN4474, he was told it was a fighter and descending.[42] Scientific American rated it as one of the worst user interface disasters.[43]

Ooof that is a boneheaded design decision.

I can guess why this maybe isn't a thing, but why are there no electronic guides for this? The plane should be able to figure out via GPS and its compass orientation which runway it's on. If you enter in 01 but end up on 10, the plane should be able to figure out it's pointing the wrong way and is in the wrong place.

I fly a bugsmasher (albeit a really nice one) which does exactly that. If I put everything in the computer and then lineup in a different runway, it will literally yell at me and say... wrong runway!

On some jets there is an annunciation system(RAAS) that also yells at the pilot all the time saying where he is... even in the sky. For instance, as he's about to land, it yells "approaching 28R", or on the ground, "on rwy 28R"

So the tech exists. The challenge is that there are a lot of older planes flying around, tech in that highly-regulated environment is slow-moving, etc.

> The plane should be able to figure out via GPS

Commercial planes don't do much with GPS. Flight systems are slaved to the Inertial Navigation System.

> If you enter in 01 but end up on 10, the plane should be able to figure out it's pointing the wrong way and is in the wrong place.

Another sibling post already talks about this.

Note that the only thing the plane can do is to warn.

This isn't true any more. The vast majority of commercial flights navigate with GPS, and follow GPS waypoints with the AP. They are so accurate that international flights across the ocean apply SLOP (strategic lateral offset procedure) to the route so they don't run into each other.

> The vast majority of commercial flights navigate with GPS

Citation needed. Which planes? Can you even take off without configuring your INS? Are the instruments slaved to the GPS system now?

Citation not needed. I'm a pilot. Inertial systems provide attitude and heading information, but is only a backup for navigation. INS cannot deliver the required navigational performance and is only used to cross-check GPS and to provide a backup in case GPS fails.

This does exist, but isn’t common. Some newer jets do have something like this. When the A350 has its first flight out of JFK the computer automatically aborted the takeoff because it thought there wasn’t enough runway. Turned out to be a false abort.

I was thinking the same thing, at least a warning.

And for the punching in the wrong weight, the system should be able to determine weight from acceleration dynamics and issue a warning as soon as the plane moves.

“Aviation experts say airliners need to lift off the ground with enough runway left to abort a takeoff“

That’s not accurate. While the aircraft shouldn’t be nearly hitting the end of the runway on takeoff it’s normal for larger jets to hit a point before takeoff where they couldn’t stop before the end of the runway.

Pilots call that point V1 during the takeoff roll, which means whatever happens you need to take off. If one of the engines blows up, you still take off. When V1 is called on takeoff standard procedure is to take your hands off the throttle controls since a ground abort is no longer available as an option.

The pre-takeoff briefing usually includes something like the captain saying if there are any problems after V1 we’ll take the problem into the air with us and troubleshoot from there.

... and for the curious, there is a V2 which is the velocity the plane needs to reach in which it can safely climb with only one engine!

And for the further curious there are a bunch of 'V' speeds.

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

Interesting, still remaining in a max 3 characters coding, wouldn't it make sense to renumber/redenominate runways using (say) alpha1-alpha2-alpha3?

Where:

alpha1 is a letter from A to J (10 letters/values 0-9)

alpha2 is a letter excluded R from P to Z (10 letters/values 0-9)

alpha3 is either L or R

So, runway 10L would be BPL and 01L would be AQL.

It still remains the possible error between L and R, though.

I don't know the reason why runways are called "Left" or "Right", I mean, even without the typo doesn't having two runways # 10 possibly create some confusion?

More generally "similar" codes should IMHO be avoided, most probably there are reasons (that I don't know about) why a number of airports have their taxiways/runways named/numbered as they are (possibly ingenerating confusion).

It seems like the crash at Linate Airport:

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

ultimately was caused by the poor visibility and the confusion between the R5 and R6 (maybe if they were called - still say - L5 and R6 or 22 and 87 the Cessna pilots wouldn't have made their error)

The numbers have a meaning aside from telling the runways apart: they're the azimuth of the runway divided by 10 degrees. So runway 10 has you taking off at a heading of 100 degrees, or a little south of east. This matters because you hear the runway numbers over the radio and can picture in your head where the other planes are and where you need to be to line up to land.

Would a simple solution be to "lie" about the runway direction by a few degrees: instead of runways 10 and 28, bump it up to 11 and 29 (or down if that's a smaller lie). DFW is apparently comfortable having numbers slightly off from the true direction, since it has 5 parallel runways, 17L, 17C, 17R, 18L, and 18R, all of which are at 175.4º.

I was confused by the comment saying that they'd "never consider that". There is precedent for exactly this sort of thing, even in the US -- like the example you cite!

Why not just always take off using the settings for the shortest distance?

Is this all about cost savings?

Noise abatement and wear on the engine. I, too, thought that this perhaps was an extreme measure for such a slight gain... i mean, how long is a plane on full thrust on take-off? 15 secs? 20?

But then a jet mechanic showed me some graph comparing wear and engine de-rates (the technical term for this less-than-100%-takeoff) and it has a CONSIDERABLE effect on the lifetime of the engine, far more than I was thinking.

Does anyone have a link to a chart with these?

Can’t find anything on Google.

[angular misinterpretation of supposed-problem-with-renaming runways "10", as the opposite-direction versions of "28"/282-degrees, deleted]

Not sure where you got 77.8 degrees from. THe opposite of 282.2 degrees should be 282.2 - 180.0 = 102.2 degrees IMHO. Which means the label of 10 L/R is correct.

77.8 = 360 - 282.2, or the mirror image of 282.2 degrees across the 0 degree line. That's a sort of "opposite"—just not the one the article was referring to.

Aha, yes, your math is correct & explains the "10"! I was not-fully-awake figuring the opposite compass-heading as (360-282.2), which is actually just the opposite-rotation-from-north, not the 180"-opposite direction. Got my symmetries mixed-up.

Landing at SFO always scares me a little bit. The way you see runway/land only few seconds before plane touches the ground is insane.

Depends where you're sitting on the plane, I guess. My experience is seeing land a few seconds after touching the ground.

Lol all the accidents that never happened blow my mind :D

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