Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

NTSB Issues Investigative Update on San Francisco Airport Near Miss

ntsb.gov

Post reply on HN
Print view View original

61–70 of 123 posts

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#61

Post by TrickyRick »

mseebach wrote: post #47
TrickyRick wrote: post #42

Earlier quoted context omitted.

Does the NTSB do what-ifs? Seems odd for an investigative body to do guesswork on what type of disasters could have occurred.

Agreed. It's fairly uninteresting (from an accident-prevention perspective, not a news-selling one) to muse about cutting it close, as soon as you get into seconds-territory, you're way too close. The fuck-up was lining up for the wrong approach in the first place, landing on the taxi-way is insanely dangerous, even if it's empty.

That's what I think as well, it should be sufficient to know that terrible things would happen and like you say, just getting in to a situation like that is bad enough.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#63

Post by tolien »

TrickyRick wrote: post #44
reustle wrote: post #41

Earlier quoted context omitted.

On top of that, storage is cheap. They can probably afford to keep conversations longer than 24 hrs.

Storage is cheap today, it wasn't 30 years ago when these rules were put in place (And probably some of the systems manufactured)

Of course the FDR/CVR might be newer but the airframe is 25 years old: https://www.flightradar24.com/data/aircraft/c-fkck

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#64

Post by rurounijones »

URSpider94 wrote: post #17
rcthompson wrote: post #13

Maybe taxiways parallel to runways shouldn't be a thing.

How do you propose to get to and from the runways?

I may be putting words in OPs mouth here but I imagine he meant not putting parallel taxiways so close to the main runway.

I know that space restrictions make this very tenuous but I must admit that looking at the overhead on https://ntsb.gov/investigations/Pages/DCA17IA148.aspx that the taxiway marked C looks a lot more like a runway than the one marked F. (due to the width maybe?)

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#65

Post by alexeckermann »

LittlePeter wrote: post #62

How about using different colour lights for taxiways and runways. They are already using different colour tarmac lines: yellow vs white.

> Lights for taxiway C were also on and set to default settings that included centerline lights (green) along its length. Default settings also included edge lights (blue) and centerline lights (green) illuminating the transition or stub taxiways from the runway to the taxiway.

> Runway and approach lighting for runway 28R were on and set to default settings, which included a 2,400-foot approach lighting system, a precision approach path indicator, touchdown zone lights (white), runway centerline lights (white at the approach end), runway threshold lights (green), and runway edge lights (white at the approach end).

Taxiway: centre green along length, blue edge lights. Can have planes on it. Runway: centre white along length and edges (also landing zone), perpendicular green at end thresholds. Should not have planes on it.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#67

Post by slavak »

TrickyRick wrote: post #42
phire wrote: post #24

Earlier quoted context omitted.

And they cut it extremely fine. The final NTSB report will probably calculate this, but I'm guessing if they had waited another second or two before shoving those throttles forwards they would have hit a plane (or three). Whats even more scary, is I get the impression that the pilots only shoved the throttles forwards because the tower told them to abort.

Does the NTSB do what-ifs? Seems odd for an investigative body to do guesswork on what type of disasters could have occurred.

The NTSB does not do what-ifs in the sense of calculating expected body count had an accident not been averted. They do, however, often investigate the performance envelope involved in an incident/accident and the timeline for possible corrective actions. So in an investigation it's quite common for the NTSB to look into how initiating corrective action at different points in time would have affected the outcome. e.g.: Sentences like "the pilots could have [taken corrective action X] until Y seconds before collision is a pretty standard sentence to see in an investigation report.

This kind of information is important for determining the available safety margin and the proper changes to recommend in order to prevent similar incidents in the future.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#68

Post by slavak »

mathgenius wrote: post #18
rrmm wrote: post #12

Earlier quoted context omitted.

Ugly stuff. I'm glad it ended up as a miss. This incident as well as the previous ones shows that pilots need better support in these conditions. Lots of airports are set up with multiple parallel runway configs. It wouldn't be all that difficult to add computer driven confirmations of the runway an aircraft is approaching on. Given the frequency of these incidents as well as the cost of the consequences it seems lik…

> but will add another safety catch. The problem with these things is how do they interact: what do you do in the cockpit when several alarms are going off at the same time? Just adding "one more alert" seems easy but... This is actually a deep problem with automation, how do the parts interact. When writing software this is a constant battle, between modularity and connection.

It's actually even worse than that: In more than one aviation accident multiple alarms and alerts actually served to confuse the pilots as to what's going on, causing them to not perform the action that would have saved the flight.

Information overload in the cockpit is a very real thing, particularly in an already task-saturated time like the landing approach. It's entirely unclear that adding yet another alert chime requiring the pilot's attention would help anything.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#69

Post by pjc50 »

viraptor wrote: post #20

I've seen people mentioning this could be a big disaster, but I'm curious exactly what the effects could be. Specifically, ignoring the wheels for the moment, would the hull of the landing plane slide off on contact at all, or would the planes just get squashed? I have no intuition about friction / stiffness of materials at that scale. (I'm also assuming the planes were at least a little bit offset to the side) With…

Large objects tend not to be stiff against collision. It would look like a high speed road crash - remember that the landing plane is travelling at over 150km/h.

Re: NTSB Issues Investigative Update on San Francisco Airport Near Miss

#70

Post by zkms »

So the guy keying up and saying "Where is this guy going?" and "He's on the taxiway" might actually have made a difference in the outcome, huh:

> The flight crew of the first airplane in queue on taxiway C (UAL1) transmitted statements regarding ACA759, one of which mentioned the alignment of ACA759 with the taxiway while ACA759 was on short final (see figures 2 and 3).

> The flight crew of the second airplane in queue on taxiway C switched on their airplane’s landing lights as the incident airplane approached.

Post reply on HN