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Malcolm

A380 Wake Turbulance

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Is it time to rethink safe separation distances for the A380s?

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Qantas superjumbo 'nosedives' over Pacific after hitting wake turbulence of other plane

'It was an absolute sense of losing your stomach.' An aircraft's wake turbulence consists of two vortexes spinning in opposite directions. No injuries were reported

A Qantas Airways Ltd. A380 superjumbo suddenly lost altitude for about 10 seconds more than 30,000 feet above the Pacific Ocean after flying through the wake of another plane.

Flight QF94, two hours after taking off from Los Angeles to Melbourne on the night of June 10, plunged upon hitting the wake turbulence of another Qantas A380 that was on its way to Sydney, the Australian airline said in a statement. No injuries were reported. The planes were separated by 20 nautical miles and 1,000 feet in altitude.

According to one of the passengers, Australian radio host Eddie McGuire, QF94 dropped and turned slightly, almost like going over the top of a roller-coaster. After leveling off, the captain explained what had happened and said the crew had asked for a different flight path, McGuire said on the radio on Thursday.

An aircraft’s wake turbulence consists of two vortexes spinning in opposite directions, and large and relatively slow-moving planes produce the most powerful forces, according to Australian aviation authorities. In the right conditions, the vortexes can hang around for more than three minutes. Unrecoverable induced rolls are among the biggest risks to nearby planes.

The lady sitting next to me and I screamed and held hands and just waited but thought with absolute certainty that we were going to crash

It’s tough to completely eliminate the risks from wake turbulence, Qantas Fleet Safety Captain Debbie Slade said in the airline’s statement.

“Aircraft are designed to handle it safely,” Slade said. “We always recommend passengers keep their seat belt firmly fastened at all times just as pilots do in the flight deck.”

The Australian newspaper cited a passenger on QF94, who described a 10-second freefall about two hours into the flight.

“It was an absolute sense of losing your stomach and that we were nosediving,” Janelle Wilson told the newspaper. “The lady sitting next to me and I screamed and held hands and just waited but thought with absolute certainty that we were going to crash. It was terrifying.”

Flying into the vortexes can be like hitting a wall, according to a wake turbulence guide by the Federal Aviation Administration. Between 1983 and 1993, there were at least 51 accidents and incidents in the U.S. from probable encounters with wake turbulence. Those incidents killed 27 people and damaged or destroyed 40 aircraft, the FAA said.

The two Qantas jets, which both took off from Los Angeles, were on flight paths assigned by U.S. controllers and were flying at a safe distance, said a spokesman for Qantas. Australia’s air-safety authority said Thursday it has reviewed Qantas’ report on the incident and it’s not opening an investigation.

 

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The absolute worst wake turbulence I’ve encountered was from following the same vectored descent path behind an Asiana A380. Our 777 had just passed through 10,000’ on a clear day and the extremely violent turbulence lasted several seconds. Immediately afterwards I noticed there was no wind at all so whatever air that “Super” kicked up had not moved an inch.

Got to give that beast lots of room. 

Edited by blues deville

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2 hours ago, Rich Pulman said:

I think it’s time to rethink the definition of “nosedive”.

I'm surprised they didn't manage to fit "air- pocket" in the article somewhere.

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5 hours ago, J.O. said:

I know an A320 captain who’d say the same thing about your 777. 

Ha ha. Yes I suppose it’s all relative. :)

I once passed behind a westbound AF Concorde over France as we headed south at the same altitude in a 757. ATC warned us of possible wake turbulance. We didn’t know what to expect but it was the equivalent of a small parking lot speed bump. Nothing at all. 

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My pet peeve is how inconsistent ATC (thinking Edmonton Centre for this story) can be about reporting crossing heavy and super traffic, while pointing out distant, non-crossing stuff. 

We were coming east and got about three of '2 o'clock, 1000' below you, no conflict' kind of things.  We then noticed converging traffic, asked about it, ; oh that's a  XXX 380, he's 1000 feet above you, you'll pass 10 miles behind, no conflict'

We climbed..... the controller seemed nonplussed by it all, sort of the equivalent of 'whatever'.

Vs

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Wake separation is rarely considered for aircraft in cruise. As long as you meet the altitude and distance requirements, ATC is happy. Time should be considered too in order to avoid wake.

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Vsplat,

Interesting comment!  We are trained and obligated to pass traffic information based on where the airplane is at.  In fact, if no overlap of the targets will happen or if we operate at more that what is required for wake-turbulence separation, we don't have to give traffic info.

I agree that the latest incidents indicate that a review of the criteria might be wise.

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I agree, the change has to be made at the policy level.   Clearly, you guys have to follow your rules like we do ours, and I can see how keeping chatter down when you're working multiple flights and frequencies has a safety impact.

These 380 wake encounters  seem to be far worse than predicted, so it would make sense to revisit the separation criteria, both vertical and lateral.

I imagine an increase in separation will affect capacity, so it will be a complex discussion.  That said, things also get pretty complicated when you experience a jet upset at 350 or hit severe turb level wake with carts in the aisles, so choosing from difficult menu items seems inevitable.

Vs

Edited by Vsplat
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