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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

#121

Post by Filligree »

lmm wrote: post #117
PhantomGremlin wrote: post #38

From the article: They then set the thrust levers to idle and raised the aircraft’s nose, before selecting take-off and go-around power and regaining straight and level flight at 31,000ft. Can anyone familiar with these aircraft opine on why the pilot decided to select TOGA in order to complete recovery? They were at perhaps 28,500 feet at the time. Seems like a a panic reaction.

Not familiar but TOGA is just the aircraft-idiomatic version of "maximum power", no?

Yes, and it wears the engines out much faster than any lower setting would. Grandparent post has a point, though it probably does have to do with recovering as quickly as possible.

Re: A330 flight control laws saved Voyager, inquiry finds

#122

Post by CaptainZapp »

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…

Not really. My observations go for intra-European flights, though.

You're usually also not yelled at when queuing for the loo, provided the seat-belt sign is off.

What I do notice a lot, though, is passengers that unbuckle half a second after touch down.

To me this seems incredibly stupid.

For starters: it's really dangerous to them and by extension to their fellow passengers and to emphasize the idiocy: They're off the plane exatly zero seconds earlier than when they just stay buckled up until the plane arrives at the gate.

Personally, I just stay buckled up, while sitting. The inconvenience is minor. Especially compared to the inconvenience when your head crashes through the overhead bin, due to sudden turbulences.

Re: A330 flight control laws saved Voyager, inquiry finds

#123

Post by mannykannot »

colanderman wrote: post #69
mikeash wrote: post #18

Earlier quoted context omitted.

It literally says "indicated air speed." There's no need for interpretation or assumption. If I saw a raw airspeed without and qualifier, I'd probably assume it meant indicated speed. But I fly small planes where that's the only airspeed available. If you want true airspeed, you have to take what's indicated and convert manually.

When coining new terms at my day job (software engineer) I try to avoid terms like "indicated air speed" for the reason that part of the term – "indicated" in this case – is easily ignored by those less familiar with the terminology, because it seems superfluous. (In this case, "indicated" to a layperson simply means "it was shown on a dial". In that interpretation, it carries little information and hence gets ignore…

Indicated airspeed is not a term for laypeople. Its meaning and significance is well understood by every pilot and aero engineer.

Re: A330 flight control laws saved Voyager, inquiry finds

#125

Post by spuz »

Pxtl wrote: post #59
JBReefer wrote: post #48

Earlier quoted context omitted.

The article states there was 198 souls on board

The article is confusingly worded, mentioning 25 passengers and 7 crew in another part... Which are also described as 25% of occupants, but that's not 25% of 198.

Thanks, those figures were confusing me. I wasn't sure if there were 32 or 198 people on board.

Re: A330 flight control laws saved Voyager, inquiry finds

#126

Post by mannykannot »

sk5t wrote: post #23
lutusp wrote: post #10

Earlier quoted context omitted.

The speed of sound varies with altitude. Nevertheless, at 30,000 feet, Mach 1 is 1,091 km/h, so the original statement is not correct (mach 0.9 at 30,000 feet would be about 982 km/h).

My takeaway/learning is that "knots indicated airspeed" is a measure of pressure due to the aircraft mushing its way through the atmosphere, and is vaguely in proportion to actual_airspeed * altitude, and from my non-pilot's perspective ought to be expressed in bars or torr or something else meant for pressure and not velocity or distance.

You are not going to like 'density altitude' then, and the terms 'light year' 'parsec' and 'electron volt' will blow your mind.

Despite the efforts of standards bodies to regularize everything, people continue to use measures that match their purpose.

Re: A330 flight control laws saved Voyager, inquiry finds

#127

Post by msandford »

dorfsmay wrote: post #108
cyberferret wrote: post #94

Earlier quoted context omitted.

Bear in mind that the AF447 crash was primarily due to a junior officer not knowing basic flight principles. Visibility of the side stick to the other two crew (the captain had come back into the cockpit and was positioned between the first and second officer) is an issue, but I am not sure that central style yokes like Boeings have would have been a huge help to a crew already overloaded with an insurmountable amoun…

In the case of AF447, the first officer (Robert) has to constantly ask the second officer (Bonin) what he is doing and why he is climbing, he's clearly worried about air speed (starting at 2:10:16 in [1]. Had the FO had direct control over the input, he could have felt that the SO was pulling back, and push back the column in neutral himself. In the case of Crossair 498 (your first link), the copilot knew the captain…

> In the case of AF447, the first officer (Robert) has to constantly ask the second officer (Bonin) what he is doing and why he is climbing

The fact that this happens at all makes me think that there could have been a hardware malfunction or that something got wedged forcing the stick back ever so slightly. So FO says "why are you pulling back?" and SO doesn't even respond since his hand isn't on the control.

In this case the Boeing system wouldn't have stepped in, granted. But in this case the Boeing system also wouldn't have let things get so far so fast. It's much, much harder to accidentally jam a big control yoke so far forwards. It would also take more than the weight of a camera to do so.

The title should read "Airbus' automated flight control conflict resolution system saves plane from problem that Airbus' poor cockpit design allowed to happen in the first place" but that's not catchy.

Re: A330 flight control laws saved Voyager, inquiry finds

#129

Post by DonaldFisk »

colanderman wrote: post #69
mikeash wrote: post #18

Earlier quoted context omitted.

It literally says "indicated air speed." There's no need for interpretation or assumption. If I saw a raw airspeed without and qualifier, I'd probably assume it meant indicated speed. But I fly small planes where that's the only airspeed available. If you want true airspeed, you have to take what's indicated and convert manually.

When coining new terms at my day job (software engineer) I try to avoid terms like "indicated air speed" for the reason that part of the term – "indicated" in this case – is easily ignored by those less familiar with the terminology, because it seems superfluous. (In this case, "indicated" to a layperson simply means "it was shown on a dial". In that interpretation, it carries little information and hence gets ignore…

Those less familiar with the terminology generally don't fly aeroplanes. Indicated air speed is different from true air speed and ground speed, but this is essential complexity - pilots need to know it.

Indicated air speed is determined by measuring pressure in the pitot tube (https://en.wikipedia.org/wiki/Pitot_tube) and is shown on the air speed indicator, which on an A330 is on the Primary Flight Display (https://en.wikipedia.org/wiki/Primary_flight_display). Important speeds such as stall speed (https://en.wikipedia.org/wiki/Stall_(fluid_mechanics)#Speed) and never exceed speed have constant values of indicated air speed.

True air speed can be calculated if you know the air pressure, which depends on the altitude and outside air temperature. Altimeters work by measuring air pressure.

It's a good idea when reporting something to take into account the readership, and to a lay audience explain things which are counter-intuitive.

Re: A330 flight control laws saved Voyager, inquiry finds

#130

Post by raverbashing »

Animats wrote: post #88

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…

A similar system is beginning to roll out in case of Cabin depressurization, the plane descends and enters a holding pattern until somebody hopefully gets back from hypoxia (there's a good Smarter Every Day video about this)
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