AA 757 loses 7500ft in turbulence encounter

[andrasz]

I'm surprised it has not been picked up here, reported on AVH. Incident happened 30 August:

An American Airlines Boeing 757-200, registration N177AN performing flight AA-213 (dep Aug 29th) from Miami,FL (USA) to Brasilia,DF (Brazil), was enroute at FL350 about 160nm west of Caracas (Venezuela) when the aircraft lost more than 7500 feet within a minute. The crew recovered the aircraft below FL275, then radioed "We lost altitude due to severe turbulence and are climbing back to FL350".

It does not sound like a controlled descent... Anybody in a position to enlighten us ?

[AMS]

perhaps there is a clue in the following:

"The crew recovered the aircraft below FL275, then radioed "We lost altitude due to severe turbulence and are climbing back to FL350"."

[poorjohn]

More generally, I hope a bunch of scientists somewhere have been granted a pot of money to tell us if the atmosphere has already become a significantly more dangerous place than our aircraft and systems were designed for. Some folks may wish it weren't so (and despite my individual thought that the atmosphere 'seems' to be more violent than a couple of decades ago, they may well be right).

[Stanwell]

An interesting 'incident'. The detail will also be interesting.


poorjohn's post reminds me of that famous exclamation from Chicken Little...

[andrasz]

perhaps there is a clue...

Let's just say if that aircraft was under control at all times, it was a helluva downdraft...

[jmmoric]

Is the aircraft under control when you loose 7000+ feet from something you can't control?

[Stanwell]

....just like the motorcyclist on another thread who, quote... "I was in complete control until I hit the fence".

[moonburn]

atmospheric disturbance

PJ, Funny you should say that, I think you may find that is not an ""individual thought"" if they asked enough of us it might even become an established fact.

[Herod]

I agree with PJ's point. I've been retired now for ten years, but I reckon in the fifteen or so years before that the average tops of a CB in Europe went up by several thousand feet. Perhaps someone with a met. background would know the facts.

[glendalegoon]

simply look up the definitions of turbulence both severe and extreme to find if the plane was in control

;-)

funny, if I had lost 7500 feet in turbulence, I don't think I would climb back up to see it again!

[justanotherflyer]

I reckon in the fifteen or so years before that the average tops of a CB in Europe went up by several thousand feet.

Curiously enough, the average height of cloud tops is, in fact, falling.

[Herod]

Ah well, I retired in Sep '04, so that was before it really became noticeable!

[captplaystation]

Gone over the Alps at F410 sometimes when that wasn't nearly enough . . . certainly wasn't how it was portrayed in my Met exam for my ATPL circa 1983.

I don't remember the level of turbulence en-route in Europe as being so severe 20 years ago. . . is it just my imagination ? or I am becoming sensitive with age. . . . . . bless

[Sober Lark]

Not to worry, you're not imagining it. New classifications of 'severe turbulence' are being discovered all the time.

[Nemrytter]

More generally, I hope a bunch of scientists somewhere have been granted a pot of money to tell us if the atmosphere has already become a significantly more dangerous place than our aircraft and systems were designed for.

I've applied for funding for something similar to this for several years, it's only in the last ~18 months that funding bodies have decided it's worth looking at.

Curiously enough, the average height of cloud tops is, in fact, falling.

The other poster was talking about CBs, not clouds in general. The reduction in height was due to a reduction in Cirrus clouds.

[Ian W]

The Accumulated Cyclone Energy (ACE) has dropped globally over the last few years. There have been less hurricanes and less tornadoes. The 'global average temperature' (which is not really a useful metric**) has risen by just over a degree Centigrade since the beginning of manned flight. In the last 17 years there has been no statistically significant atmospheric warming (called the 'Pause' by the IPCC).

What has happened is that over the last few years the jetstreams have become more latitudinal (i.e. more lobes and those lobes extending more equatorward - called the Polar Vortex by the weather men in the USA - see earth :: an animated map of global wind, weather, and ocean conditions) probably because the Hadley convection cells that are driven by the convection in the Intertropical Convergence Zone are less active (lots of discussion and research in that area). The latitudinal jetstreams could mean that associated turbulence with both jetstreams and jetstreaks, is found in areas where it normally would not be expected.





** The average global temperature has been described as being as useful as an average phone number.

[oldoberon]

IAN W

The average global temperature has been described as being as useful as an average phone number.

not seen that one before , great one :-)

[Nemrytter]

The Accumulated Cyclone Energy (ACE) has dropped globally over the last few years. There have been less hurricanes and less tornadoes.

To actually address Herod's original point: The average max altitude of a CB over Europe has increased by about 400 meters (~1200ft) between 2007 and 2014. On a global scale there is no significant trend.

As for the rest of your post: That's better confined to jet blast where there's a thread full of similar rhetoric.

[Algol]

How many times have you heard passengers say 'oh it was terrible, we hit an air pocket and dropped like a stone'?
In 30+ years of flying I've never come across one of these mysterious 'air pockets'. This must have been one!

[sherburn2LA]

surely you would be more likely to drop in a 'no air pocket'