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A330 flight control laws saved Voyager, inquiry finds

flightglobal.com

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Re: A330 flight control laws saved Voyager, inquiry finds

#81

Post by drewkett »

brandmeyer wrote: post #71
sk5t wrote: post #21

Earlier quoted context omitted.

So it does. I still find this disunion of UOM disagreeable, in the way that "in thousandths, take 300 grams of acetaminophen twice daily" is troubling.

The aircraft has a maximum speed rating, beyond which the structure may fail. That speed rating is based on the aerodynamic forces on the aircraft, which are proportional to the indicated airspeed, not the true airspeed. That's why the instrument panel almost universally shows IAS. That way the pilot doesn't need to perform an altitude-based nonlinear conversion in his head during an emergency to see that he's about…

Just so you know the forces are actually proportional to the square of equivalent airspeed which is indicated airspeed adjusted for the compressibility of the air at the sensor. Indicated airspeed is still a better number than true airspeed for approximating the aero forces

Re: A330 flight control laws saved Voyager, inquiry finds

#82

Post by robzyb »

rwmj wrote: post #4

The link I posted is the only good technical summary, but there are plenty of others about the pilot's ongoing military trial, eg: http://www.telegraph.co.uk/news/2017/02/06/bored-raf-pilot-s... 'Bored' RAF pilot sent 187 passengers into a nosedive 'while playing with his camera'

> The link I posted is the only good technical summary

Agreed, except for...

> Its automatic high-speed protection system was triggered 3s later, with a maximum indicated air speed of 358kt (662km/h), or Mach 0.9, recorded.

Re: A330 flight control laws saved Voyager, inquiry finds

#83

Post by closeparen »

kristianp wrote: post #20
Someone wrote: post #7

"seven dented ceiling panels, 50 damaged in-flight entertainment sockets" The article doesn't state it, but that's because the passengers, like the co-pilot, fell towards the ceiling of the airplane during this episode. Apparently, the headphone cables are stronger than those sockets.

It's a safety concern that at least 50 passengers didn't have their seat-belts on!

Is it me or has seat-belt-sign discipline gone out the window?

Over my December travels, dozens of passengers on all 4 segments I flew openly flaunted the seat-belt sign, getting up to go to the bathroom and standing in the aisle waiting for it in full view of flight attendants, who didn't say anything. I broke down and did so myself, as the seat belt sign was on for the vast majority of the flight and I was getting desperate.

In the years prior, I've been sternly commanded to get fuck back to my seat when queueing for the bathroom, even with the seat belt sign off. Never observed anyone out and about while it was on. Maybe the only care in the front of the plane, since you might be preparing to rush the flight deck or something?

Any frequent fliers notice this change?

Re: A330 flight control laws saved Voyager, inquiry finds

#84

Post by xenadu02 »

jsmthrowaway wrote: post #46
tropo wrote: post #43

Earlier quoted context omitted.

Nope, it wouldn't happen in a Boeing aircraft. This is a well-known Airbus defect that was a contributing factor to the crash of Air France Flight 447. Boeing uses traditional controls. It's like a race car steering wheel on a big movable stick. It is really easy to see how the control is positioned. Airbus uses a small joystick off to the side. It is force-based like a Thinkpad pointing stick, so it barely moves whe…

This is the partisanship I'm talking about, for what it's worth. I've flown an A320 in a full-size simulator and my experience with its sidestick, even in that simulator environment, does not match what you are describing. The sidestick moves quite far and quite noticeably[0], and does not behave like a ThinkPad. The aircraft simply ignores drastic input, which might be what you're thinking of with that assessment? A…

I don't think the sidestick is the problem, it's the lack of feedback and the fact that the system ignores conflicting input.

Boeing undoubtedly does that one aspect correctly: Regardless of the type of stick the two inputs are linked so if the captain is giving strange input it would be immediately obvious to the copilot. There is no reason Airbus couldn't implement the same system on their sidesticks.

The fact that conflicting input causes the system to ignore both seems like downright insanity and based on the assumption of one input being defective, rather than conflict between pilots. A simple fix might be to include a hand detection mechanism and ignore input from the stick that doesn't have a hand present unless it is the only input and is not overridden.

Re: A330 flight control laws saved Voyager, inquiry finds

#85

Post by nathancahill »

closeparen wrote: post #83
kristianp wrote: post #20

Earlier quoted context omitted.

It's a safety concern that at least 50 passengers didn't have their seat-belts on!

Is it me or has seat-belt-sign discipline gone out the window? Over my December travels, dozens of passengers on all 4 segments I flew openly flaunted the seat-belt sign, getting up to go to the bathroom and standing in the aisle waiting for it in full view of flight attendants, who didn't say anything. I broke down and did so myself, as the seat belt sign was on for the vast majority of the flight and I was getting…

I've noticed that too. I used to do that myself, until I hit some of the worst turbulence of my life flying in to Denver a couple years ago. Whacked my head pretty hard on main cabin ceiling (the plane dropped ~20ft without warning and I didn't). Ever since then I've worn my seat belt for as much of the flight as possible.

Re: A330 flight control laws saved Voyager, inquiry finds

#86

Post by wapz »

6stringmerc wrote: post #80
ririau wrote: post #76

Earlier quoted context omitted.

Remember that most of the sources of typical crashes or problems have been eliminated. Which means that accidents happen they're always freak accidents.

Not really, that recent crash in San Francisco had alarms going off like crazy and the idiot pilot still managed to crash the plane. Once you read enough NTSB reports / bulletins about General Aviation accidents (usually only big stuff makes the news) it becomes very clear that accidents happen and bad decisions happen. Like turning off the wrong engine...

Was this the Korean (whichever of the companies) airlines crash? I didn't read up too much into it after the fact.

Re: A330 flight control laws saved Voyager, inquiry finds

#88

Post by Animats »

The next step up is auto-GCAS. That system, which started going into USAF F-16s in 2014, has already saved four planes and pilots. Here's a video of the cockpit view. The pilot had briefly lost consciousness during a high-G maneuver, and the auto-GCAS system rolled the plane wings-level and pulled it out of a dive and into a mild climb.[1]

Work is going on to develop auto-GCAS for aircraft without the maneuverability of a fighter.

[1] http://aviationweek.com/air-combat-safety/auto-gcas-saves-un...

Re: A330 flight control laws saved Voyager, inquiry finds

#89

Post by comex »

fryguy wrote: post #75
m_mueller wrote: post #63

> "Up to 24% of the aircraft occupants were rendered temporarily unfit for duties following the incident" Gotta love the officialese for 'people puked everywhere'....

Or flung into the ceiling headfirst at 0.5g and then back to the floor at 2g. Presumably that could cause injuries other than motion sickness.

Indeed. From the Telegraph article linked in another comment:

> Flt Lt Nathan Jones, the co-pilot, suffered a cut to the head, a fractured back, a prolapsed disc and nerve damage.

> The court heard 14 passengers were so badly hurt they were unable to fly back to the UK.

Re: A330 flight control laws saved Voyager, inquiry finds

#90

Post by _Codemonkeyism »

chanandler_bong wrote: post #19

From the headline, I could not figure out how an A330s flight control system could have any influence on spacecraft launched in 1977. Surely there would be no way to port the code and the storage on the Voyagers is tiny... at least until the V'ger Mk. I upgrade.

Incidentally my first thought too.
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