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Mallard Down in Perth

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Old 28th Jan 2017, 06:29
  #101 (permalink)  
 
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Originally Posted by onetrack
It's entirely likely the left turn, which changed the airflow from crosswind to tailwind, along with reduced airspeed in the bank, led to the port wing stall, and the resultant unrecoverable situation.
Are you a pilot? If so, you will need to sit your theory again.
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Old 28th Jan 2017, 06:39
  #102 (permalink)  
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The video reminded me a bit of this accident. Very different in size of aircraft but similar in outcome.

Yes, the physics probably will be shown to be similar.

However, probably not all that reasonable to compare the Perth mishap with Holland's cowboy attitudes. While the one, possibly, will prove to involve an unfortunate degree of inexperience ... the other pilot, while having considerable experience, led spades in wilful stupidity which proved to be trumps on the day.

Dr Kern's article is worth a read, I think.

While I'm not overly interested in buying into reruns of the downwind turn arguments, the presence/absence of horizontal/vertical shear is very relevant and is, I suspect, a major cause of much of the confusion. It is worth noting that the albatross exploits the latter consideration most competently.
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Old 28th Jan 2017, 06:46
  #103 (permalink)  
 
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Are you a pilot? If so, you will need to sit your theory again.
Thanks, I know I'm very tired today, however I thought what I was reading contained zero elements of fact!
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Old 28th Jan 2017, 06:59
  #104 (permalink)  
 
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Low and slow turns with an upwind carry a risk of a visual perception that the pilot needs to increase bank to complete a "normal" turn over ground. This is because the visual pilot is seeing landmarks pass by close to the aircraft telling them that the turn isn't meeting expectations Not being a pilot that's ever considered landing on the wet stuff is this visual perception still relevant over water where I presume it would be different due to lack of moving landmarks.
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Old 28th Jan 2017, 07:04
  #105 (permalink)  
 
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The aircraft doesn't care if it's blowing 300 knots, it just flies merrily along its' way.
But if that 300kts wind turns from a crosswind to a tailwind, within the space of a few seconds, you would expect some small alteration in the aircrafts flying position? Such as a loss of height?
In the initial video above, I see a Mallard travelling at a fairly steady altitude up until 17 seconds. At 18 seconds, it's losing altitude. At 19 seconds, the port wing is dropping dramatically. At 21 seconds, it's unrecoverable, due to a lack of altitude.

What is difficult to see in the video (due to the angle of videoing), is if the loss of altitude and port wing drop, is purely attributable to increased AOA, or loss of airspeed, due to initially flying too close to stall.
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Old 28th Jan 2017, 07:11
  #106 (permalink)  
 
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Errrrm....onetrack... when flying, an aircraft is always flying into a 'headwind' equal to TAS...
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Old 28th Jan 2017, 07:12
  #107 (permalink)  
 
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OneTrack, are you a qualified pilot, be it RA-Aus, GA or otherwise? I'm curious...

Because if you are... then this has not been explained to you in a way in which you have understood it and I would suggest that you speak to an instructor for further clarification.

The aircraft will fly the same through the air regardless of whether it is flying in zero wind, or 300 knots.
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Old 28th Jan 2017, 07:15
  #108 (permalink)  
 
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No, I'm not a pilot, or I would have that on my profile. I did take out basic pilot studies many years ago, but never completed them, due to other commitments.
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Old 28th Jan 2017, 07:24
  #109 (permalink)  
 
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So would not turning into a tailwind exhibit the same symptoms of windshear?
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Old 28th Jan 2017, 07:30
  #110 (permalink)  
 
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What does "turning into a tailwind" mean?

If the wind is a constant velocity an aircraft in the air never turns into a tailwind. The wind will affect the aircraft's groundspeed and track depending on which way the aircraft is heading, but the aircraft's TAS is not affected by the wind.

Now if it's a 300 kt northerly at 200' and a 300 kt southerly at 100', the aircraft will be destroyed on descent...
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Old 28th Jan 2017, 07:32
  #111 (permalink)  
 
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Originally Posted by onetrack
No, I'm not a pilot, or I would have that on my profile. I did take out basic pilot studies many years ago, but never completed them, due to other commitments.
Thanks for your honesty.

It doesn't matter which way the aircraft is travelling in the 300knot wind, it simply flies normally as every *molecule* of air is moving at the same speed so the airframe is none the wiser.

What screws things up is when the pilot tries to get to a specific point on the ground or point of reference to be at by a certain altitude and with the 300 knots of wind, it will be extremely difficult to judge, therefore a pilot may pull a much steeper turn than normal to get to that point in time. Speed may also be reduced to allow the aircraft to make the point, which can result in a stall. The aircraft needs to be flown fully within its documented flight parameters, regardless of the wind speed.
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Old 28th Jan 2017, 07:36
  #112 (permalink)  
 
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Just remember that you're standing on a planet that's evolving
And revolving at 900 miles an hour.
It's orbiting at 19 miles a second, so it's reckoned,
The sun that is the source of all our power.
Now the sun, and you and me, and all the stars that we can see,
Are moving at a million miles a day,
In the outer spiral arm, at 40,000 miles an hour,
Of a galaxy we call the Milky Way.

.....and I don't feel any of it no matter which way I turn.
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Old 28th Jan 2017, 07:56
  #113 (permalink)  
 
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Onetrack.

16 seconds into that video the ailerons are already going right.

Steve
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Old 28th Jan 2017, 08:07
  #114 (permalink)  
 
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Low and slow turns with an upwind
Really? An upwind?
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Old 28th Jan 2017, 08:38
  #115 (permalink)  
 
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Squawk7700, thanks for your patience and explanation. I'm happy to have my lack of knowledge/understanding exposed and discussed, if it means only one pilot is saved from making a fatal error anytime in the future. We all learn by discussion and demonstration, and one should never stop learning.

What is of concern, of course, is that Peter Lynch was a supposedly fully qualified and experienced pilot - yet he managed to stoof his aircraft in, with what appears to be a very basic flying error.
I'm hazarding a guess that he didn't have low-level flying training and qualifications? - which, if true, leads to a lot more questions, as to why he was allowed to fly into the Skyworks display?
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Old 28th Jan 2017, 08:47
  #116 (permalink)  
 
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What is required to get approval for a display of this type? Or was he just showcasing the aircraft? It does seem a pretty small area for an aircraft of that size to be manoeuvring in, and no escape route in the event of something going wrong such as becoming assymetric.
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Old 28th Jan 2017, 08:54
  #117 (permalink)  
 
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Without wishing to comment in specifics of the accident :

I'm hazarding a guess that he didn't have low-level flying training and qualifications?
FWIW the dangers/differences between upwind and downwind turns at low level were regarded as so significant that they used to be taught or at least demonstrated by (UK) Central Flying School instructors as part of the first low level flying lesson on a light piston aircraft , I'd guess/hope it's still taught elsewhere. As someone has already pointed out the major threat was regarded as trying to tighten a downwind turn or "wrap a turn up" to overfly a ground datum.
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Old 28th Jan 2017, 08:59
  #118 (permalink)  
 
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Oh gawd, here we go.

More approvals and training and qualifications and regulations? To land an amphibious aircraft on the water?

The ways in which pilots usually "stoof in" are well known. And those ways are usually "very basic" errors. Perhaps education, education and more education about the lessons that have been learned over and over would be a more effective solution.
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Old 28th Jan 2017, 09:01
  #119 (permalink)  
 
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This article makes interesting claims.

"...Mr Lynch had also been battling with the Civil Aviation Safety Authority to allow him to fly in the Australia Day air show right up until the 11th hour.The approval was finally granted on January 24 and a delighted Mr Lynch left a voice message on Mr McCormack’s phone that day saying: “Guess what mate, I got my type rating and everything through from CASA... and I am pretty happy about that as it means I will be in the show.”

No Cookies | Daily Telegraph

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Old 28th Jan 2017, 09:13
  #120 (permalink)  
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One question; Is anyone who has posted on this thread an Ag Pilot? Or has anyone a low level endorsement?

I'm almost tempted to say not!
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