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QF94 from Los Angeles to Melbourne Vortex

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QF94 from Los Angeles to Melbourne Vortex

Old 14th Jun 2018, 04:02
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QF94 from Los Angeles to Melbourne Vortex

https://nypost.com/2018/06/13/airlin...ying-nosedive/
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Old 14th Jun 2018, 05:09
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Interesting - I wonder about the 1000-ft altitude difference cited for two planes on the same southwesterly heading. I assume the upset plane was the lower plane (wake vortices sink), and perhaps the leading 'Bus was in the process of its first step-climb from FL320, passing through FL330? Timing is about right, and the extra lift needed in the climb would increase the vortex intensity. 20 nm equals about 2.5 minutes separation, so that makes sense.

EDIT - AvHerald says upset plane actually was SW-bound at FL310(?? - also in step climb?) but indeed the event occurred at about the time the lead plane was also starting its climb from FL320 to FL340.

http://avherald.com/h?article=4b9da5b2&opt=0
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Old 14th Jun 2018, 05:14
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"Australian television and radio host Eddie McGuire, who was on the flight, said the plane "jumped up and down for about 10 seconds" and that "somebody described it as the feeling of going over the top of a roller-coaster.""

A somewhat less breathless version by a respected newspaper...

https://www.smh.com.au/business/comp...14-p4zldt.html

Last edited by JohnMcGhie; 14th Jun 2018 at 05:15. Reason: adding appropriate emphasis
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Old 14th Jun 2018, 05:29
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Maintaining separation to avoid wake turbulence is SOP, how did this happen to Qantas pilots, the nosedive was most likely the PF repositioning the craft.
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Old 14th Jun 2018, 05:32
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Yawn. Newsworthy? Only because 'kick the National Carrier' is a game in Australia.

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Old 14th Jun 2018, 05:33
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Define "nosedive", please.
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Old 14th Jun 2018, 06:40
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For those not living in Australia, you might be interested to know that he media celebrity Eddie McGuire is know as “Eddie Everywhere”. He certainly lives up to his name, even being on an A380 as it nosedives (sic) towards the Pacific Ocean.
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Old 14th Jun 2018, 08:46
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ATSB ' take on the issue
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Old 14th Jun 2018, 09:15
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The fact that no one was injured based on the severity of the rapid descent makes me call shenanigans.
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Old 14th Jun 2018, 10:38
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Have to admit that I didn't know there was more wake generated during steady state climb, since lift equals weight in steady state, the same lift as is required in straight and level flight.
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Old 14th Jun 2018, 10:46
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I watched Eddie McGuire’s interview on TV this morning. He tried to play it down, despite being pressed by the dopey interviewer about the ‘nosedive’ on several occasions.

He added that the flight over to LA was more uncomfortable due to continual turbulence. Didn’t see that in the media!

Slow aviation news day!
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Old 14th Jun 2018, 10:51
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I'd speculate that the nosedive was the pilots trying to quickly get out of that turbulent air by promptly descending.
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Old 14th Jun 2018, 10:55
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Originally Posted by DType View Post
Have to admit that I didn't know there was more wake generated during steady state climb, since lift equals weight in steady state, the same lift as is required in straight and level flight.
I may be wrong, it is a long time ago, but I must admit I thought I was taught that for a powered aircraft lift was/could be actually less In a steady state climb than when S&L due to the contribution to the upwards force vector of the vertical component of thrust....







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Old 14th Jun 2018, 10:58
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since lift equals weight in steady state, the same lift as is required in straight and level flight
Pedant mode on/ If one is being really picky, a small portion of the weight is opposed by the thrust in a climb, so the lift require is less than level flight \pedant mode off

Wiggy beat me to it!

Last edited by BizJetJock; 14th Jun 2018 at 10:59. Reason: Slowness...
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Old 14th Jun 2018, 11:06
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When I'm in the sim, it sometimes feels like we're in a nosedive but we haven't really gone anywhere!
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Old 15th Jun 2018, 00:47
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Originally Posted by Pattern is Full
and the extra lift needed in the climb would increase the vortex intensity.
Since these were Australian crews, aircraft, had Eddie Maguire on board, and was reported in Australian papers, PIF, I'll ask you to do a Pauline Hanson: PLEASE EXPLAIN?!
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Old 15th Jun 2018, 10:38
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Originally Posted by DType View Post
Have to admit that I didn't know there was more wake generated during steady state climb, since lift equals weight in steady state, the same lift as is required in straight and level flight.
Not the case, you gain positive vertical acceleration you need more lift than cruise. Also its a not clean profile with more power.
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Old 15th Jun 2018, 10:49
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you gain positive vertical acceleration you need more lift than cruise
That would only be during the initial pitch up. Take an aeroplane steady-state climbing at a 60° angle. Wing lift, the thing that creates the vortexs, is not more. IMO.
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Old 15th Jun 2018, 16:06
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Originally Posted by hoss183 View Post
Not the case, you gain positive vertical acceleration you need more lift than cruise. Also its a not clean profile with more power.
hoss, not sure what the second sentence means but IMHO Capn Bloggs is correct with regard to the first bit.

You are (first approximation) only actually accelerating upwards until you achieve a constant rate of climb (ROC) or as Capn Bloggs describes it, during the pitch up itself (doesn’t matter whether it is a pitch up at takeoff or a pitch up to initiate a cruise climb). Once you’ve established in a steady climb you are climbing upwards but you are not accelerating upwards, and we are back to the possibility/probability of the required “wing lift” being less in the climb than in level flight due to the vertical component of thrust.
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Old 15th Jun 2018, 16:07
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OK, yes, transitioning to a climb would put a "knuckle" of increased vortex in the wake momentarily and then return to the "steady state" vortex strength - assuming the climb in thereafter unaccelerated (not a loop-the-loop!). It is highly improbable (but not impossible) that the trailing plane would fly into the preceding vortex exactly at the point where the knuckle exists.

@Capn Bloggs - an aeroplane climbing at a 60° angle will not be in a "steady state" very long - unless it's an F-18. But your point is taken.
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