AF447 fell 38,000ft in 3.5 minutes

Posy · 27-05-2011 11:11PM

God help those on board. It sounds terrifying.

sdanseo · 27-05-2011 11:13PM

Ah lads ffs. Posts reported. Theres a thread above dedicated to how the mods can beter handle this place, I'd hazard a guess not having babies allowed like you two might help.

Fukuyama · 27-05-2011 11:14PM

Big shame this. Goes to show that even in the hands of professional pilots and with highly sophisticated aeronautics engineering surrounding you; you're still in a tin can at 40,000 feet...

May all the passengers RIP.

celj · 27-05-2011 11:14PM

Posy wrote: »

God help those on board. It sounds terrifying.

Ah it's not too bad around here,a few drys*%tes but it's ..............

Oh you meant the plane.......

celj · 27-05-2011 11:19PM

CommuterIE wrote: »

Mods can you please get rid of this gob****e!

How very very dare you!!!:eek:

FlutterinBantam · 27-05-2011 11:22PM

celj wrote: »

How very very dare you!!!:eek:

jaysus.

where the fcuk were you since 2003:D

Seven posts a year:eek:

celj · 27-05-2011 11:23PM

FlutterinBantam wrote: »

jaysus.

where the fcuk were you since 2003:D

Seven posts a year:eek:

Early release!:pac:

27-05-2011 11:23PM

There's been a number of crashes related to pitot tubes over the years afaik.

CommuterIE · 27-05-2011 11:26PM

rarnes1 wrote: »

There's been a number of crashes related to pitot tubes over the years afaik.

Yes there has, one 757 crashed because bees decided to nest in them... an Aero Peru crashed in the sea killing all on boards because selotape wasn't taken off to protect them during washing

FlutterinBantam · 27-05-2011 11:28PM

rarnes1 wrote: »

There's been a number of crashes related to pitot tubes over the years afaik.

Absolutely.

If those boys get frozen or blocked up is bad bad news, for sure.

turn on the heat.

cml387 · 27-05-2011 11:59PM

The cruise phase of a long flight is very boring.
Everything is normal the controls glow comfortingly.
Then a small course deviation,nothing out of the ordinary.
A chime ,indicating an autopilot disconnection,and all hell breaks loose.
Warning messages flash up on the displays,the aircraft lurches and buckets.
Misleading readings from pilot and FO's display.
Three minutes later they're all dead.

It's a small vision of hell.

johngalway · 28-05-2011 12:23AM

sdonn wrote: »

Was it in daylight or night-time that the accident occurred? If you lose your instruments over a pitch black ocean, straight and level becomes next to impossible. Spatial disorientation.

My first thought about this is, is there, or if there isn't, why isn't there, some low tech gadget to keep a plane on the level at least, straight could be achieved by a compass I guess (or maybe not, what do I know).

But the level bit, some liquid inside a clear bubble, anything like that would work, just need watching.

CommuterIE · 28-05-2011 12:25AM

johngalway wrote: »

My first thought about this is, is there, or if there isn't, why isn't there, some low tech gadget to keep a plane on the level at least, straight could be achieved by a compass I guess (or maybe not, what do I know).

But the level bit, some liquid inside a clear bubble, anything like that would work, just need watching.

There is a free flowing compass, but how in gods name do you maintain situational awareness with that?? It doesn't tell you whether you left or right, pitching up or down...

28-05-2011 12:28AM

CommuterIE wrote: »

Yes there has, one 757 crashed because bees decided to nest in them... an Aero Peru crashed in the sea killing all on boards because selotape wasn't taken off to protect them during washing

Crazy that things like this could have caused such accidents. I seen a programme on the bees incident alright.

Passenger planes and selotape really shouldn't be in the same sentence together !

Wompa1 · 28-05-2011 12:29AM

https://www.youtube.com/watch?v=1Bs7EqlLiSs

Trevor451 · 28-05-2011 12:29AM

I thought all modern commercial aircraft have GPS that can measure airspeed?

CommuterIE · 28-05-2011 12:31AM

A good way to recover is to keep the engine thrust at 84% with the nose pitched up 5 degrees.... this applies to 757's and 737's... you maintain the same altitude at the same speed

lomb · 28-05-2011 12:31AM

CommuterIE wrote: »

Wrong!!!! To fall 38,000ft flat out in 3.5 mins would have been absolutely anyones worst nightmare.... they knew what was coming, if some didn't black out along the way down

When I went skydiving I fell 7500 foot in 40 seconds freefall, and took another 3 or 4 minutes under parachute to 'fall' the other 5500 foot.
There was no blacking out and actually I felt more alive than I ever did before...

Must have been terrifying sitting there helpless though, RIP.

johngalway · 28-05-2011 12:34AM

CommuterIE wrote: »

There is a free flowing compass, but how in gods name do you maintain situational awareness with that?? It doesn't tell you whether you left or right, pitching up or down...

If you think of it like being buried in an avalanche and you don't know which way is up or down, make a little space and spit on some snow, watch which way that baby hangs/drops, gravity tells you

So if you're flying at night, with no visual references, and no visible horizon, you could have an object on the (for want of a better word) dash that is clear, but has "level"

marked on it. This object is filled with possibly a coloured liquid. If you're turning or ascending/descending, the liquid position in relation to the level

mark should indicate what's happening.

Not explained terribly well, but you get the idea.

In navigation in hillwalking at night or fog/poor visibility I was taught to walk on a compass bearing. One guy watches the bearing, one watched the "level".

If nothing else, it buys you time to talk to ATC and figure out what's going on.

I haven't fully read this thread so I'm probably missing other large problems associated with the crash.

CommuterIE · 28-05-2011 12:35AM

lomb wrote: »

When I went skydiving I fell 7500 foot in 40 seconds freefall, and took another 3 or 4 minutes under parachute to 'fall' the other 5500 foot.
There was no blacking out and actually I felt more alive than I ever did before...

Must have been terrifying sitting there helpless though, RIP.

Agreed, the weight off the aircraft would have made them feel like a ton of bricks

Solnskaya · 28-05-2011 12:41AM

Thats nothing, I was a bit tipsy the other night and missed my footing on the stairs. I fell 6 feet in .3 of a second. Scary stuff, let me tell ya.
More seriously though, I feckin hate flying and me butts like a Mussel on a rock gripping the seat on even a normal landing, so being trapped in a plummetting coke can must be like a step from Dante's inferno.

dfx- · 28-05-2011 12:43AM

I'd say the most frightening aspect to the crash is that there's nothing especially out of the ordinary. It was flying into very strong storms that are always there, at cruising height, on the normal path, the plane didn't break up, it didn't go into a nose-dive, the plane was recoverable for a time I imagine

There's no disaster moment that makes it a one-in-a-million like the tailfin falling off (American Airlines or Japan Airways) or Concorde or the roof ripping open (Aloha) or a bird strike (US Airways), a mid-air collision or the cargo door opening (United) or a volcano (BA)...

CommuterIE · 28-05-2011 12:46AM

dfx- wrote: »

I'd say the most frightening aspect to the crash is that there's nothing especially out of the ordinary. It was flying into very strong storms that are always there, at cruising height, on the normal path, the plane didn't break up, it didn't go into a nose-dive, the plane was recoverable for a time I imagine

There's no disaster moment that makes it a one-in-a-million like the tailfin falling off (American Airways or Japan Airways) or a mid-air collision or the cargo door opening (United) or a volcano (BA)...

Well it's not out of the ordinary... thousands of people have died due to pitot tube malfunctions

partyatmygaff · 28-05-2011 12:49AM

Trevor451 wrote: »

I thought all modern commercial aircraft have GPS that can measure airspeed?

It's not that simple (Thank you Flight Simulator X...)

GPS will only measure the position of the aircraft relative to the orbiting GPS satellites. Therefore it will effectively only ever measure the speed of the plane relative to the ground. That is what is called ground speed and it has no bearing whatsoever on aerodynamic stall which is what happened to AF447.

An aerodynamic stall occurs when the plane drops below its stall speed. The stall speed differs from plane to plane and from situation to situation. During an aerodynamic stall the true airspeed is too low to support the aircraft. That is to say that there is simply not enough lift being generated by the wings due to the speed of the air passing over the wings being too slow.

For example, hypothetically speaking if there was an extremely powerful headwind a plane at full throttle could have an airspeed of 400 knots but a negative ground speed. I.e. it's moving forwards through the air mass but actually going backwards relative to the ground.

The Shtig · 28-05-2011 01:07AM

Maybe it was better that they hit the water at 11,000fps and died instantly. If the pilot managed to 'land' onto the ocean and some passengers escaped then they would be stuck 100's of miles from land, during the night while a storm was raging on with pretty much no chance of rescue.

sdanseo · 28-05-2011 02:00AM

johngalway wrote: »

My first thought about this is, is there, or if there isn't, why isn't there, some low tech gadget to keep a plane on the level at least, straight could be achieved by a compass I guess (or maybe not, what do I know).

But the level bit, some liquid inside a clear bubble, anything like that would work, just need watching.

That would be the standby ADI I talked about further down in my post. I can't imagine why or how that would fail but it's possible that in an emergency you can't go just by that, no lights, no nothing etc

Manic Moran · 28-05-2011 03:57AM

sdonn wrote: »

Was it in daylight or night-time that the accident occurred? If you lose your instruments over a pitch black ocean, straight and level becomes next to impossible. Spatial disorientation.

There is no indication that they lost their instruments. They appear to have lost one instrument, and part of basic IFR training is to identify which instrument system has broken, and how to fly without it. Frankly, the chances that they lost so many instruments as to make the aircraft unflyable on instruments alone is all but inconceivable.

However isn't there a standby gyroscopic ADI for these reasons which should have worked regardless?

Yes, which is why I am reluctant to think that not only did they lose their primary instrumentation system, but that two of three backup systems (Vacuum, electrical, pitot-static) also failed. It's theoretically possible, but incredibly unlikely, and no indication that it happened.

So if you're flying at night, with no visual references, and no visible horizon, you could have an object on the (for want of a better word) dash that is clear, but has "level"
marked on it.

Won't work. Watch this video for a perfect example.

https://www.youtube.com/watch?v=Xp2Uc9XvmjY

The man pours a cup of ice tea from a pitcher onto a glass he just placed on the dash whilst performing a complete barrel roll.

It's not that simple (Thank you Flight Simulator X...)

GPS will only measure the position of the aircraft relative to the orbiting GPS satellites. Therefore it will effectively only ever measure the speed of the plane relative to the ground

Have four satellites, and it will calculate your 3-dimensional place in space. Simple calculation will tell you the true airspeed you're going at, just most GPS nav systems are set for map view. That said, its also useless information. How fast the air is moving over the wing is far more important than how fast you are moving.

NTM

Turtwig · 28-05-2011 05:53AM

I don't know how people can say they lost their bearings in the night sky. The plane had it nose tilted upwards 35º. There's no way you couldn't notice that. Something seriously went wrong to make them decide to pitch up like that.

The pitots seem too easy an excuse.

Wibbs · 28-05-2011 10:55AM

Did you look at the video in the post immediately before your own? Yes they could be pitched up at 30 degrees at night and not notice. Your inner ear and other natural systems were evolved for upright walking and the like. They were not evolved for flight. I'm sure a trained parrot on a pilots shoulder(hmmm lightbulb moment) would notice, humans not so much. Flying "by the seat of your pants" only works in films.

An uncle of mine was flying a single seater many moons ago, knackered with fatigue and found himself exiting a cloud at a 45 degree wing angle to the ground. He went into the cloud level. Apparently very common. I seem to recall a story from one of the RAF's top test pilots in world war two. He was one of the guys who helped develop the Supermarine Spitfire IIRC. He was flying one of them after months of long hours wartime flying and found himself lost looking for his airfield. He was on the radio reporting dense fog to the airfield. They were looking up into a high altitude cloud base, but otherwise clear sky. He was flying upside down.

tails_naf · 28-05-2011 11:55AM

sdonn wrote: »

Was it in daylight or night-time that the accident occurred? If you lose your instruments over a pitch black ocean, straight and level becomes next to impossible. Spatial disorientation.

A regular descent in an A330 would be between 1500-2500fpm. An emergency descent could be two or three times that at the very most, any faster and the airframe becomes unstable.

If the aircraft was falling but pitched up, to me it would suggest total instrument failure, spatial disorientation, stall and loss of flight envelope...followed, almost inevitably, by the crash. However isn't there a standby gyroscopic ADI for these reasons which should have worked regardless?

Do they not have gyroscopes? or at least a backup based on a gyro? That should always indicate what's level / direction no matter the external conditions...

AF447 fell 38,000ft in 3.5 minutes

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