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Mallard Down in Perth

Old 29th Jan 2017, 23:48
  #181 (permalink)  
 
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Is it just me or am I the only one that doesn't want to watch her video.....
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Old 30th Jan 2017, 00:14
  #182 (permalink)  
 
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On many phones, when you swap cameras to selfie mode, the video is reversed to a mirror image
When you're looking at the screen taking the shot/video it is, but when you look at the finished product, it is as though someone took a shot of you. That is, the orientation is correct. Take a selfie with some text on your shirt: it comes out correctly when you view the image.
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Old 30th Jan 2017, 00:23
  #183 (permalink)  
 
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As flyer69 said, I hope none of you preaching the downwind turn being no different are instructors and I hope any prospective pilots reading this don't get it into their heads thinking this.

It might not be relevant to the tragedy in question but there is a reason we try to get as much out of the hopper as possible and make the first turn into wind before having to turn downwind. I reinforced the point to myself after spending 6 weeks in a wheelchair following a downwind turn in which ambition exceeded ability. If you haven't flown a heavy ag plane then you don't know what you don't know.
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Old 30th Jan 2017, 02:33
  #184 (permalink)  
 
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There's lots of talk about this accident, and turns, with varying reference to wind. I'm not a Mallard pilot, nor am I familiar with Perth, but to inform myself a little, I did some Google Earth measuring of the flying display area before commenting here. Presuming that is was the intention of the pilot to avoid flying over land (built up areas) as depicted in the flying display graphic kindly posted, let's consider dimensions:

The water area depicted on the graphic equates roughly to the runway and infield dimensions of an airport with one 8000 foot runway, and a bisecting crossing 4500 foot runway. Let alone an aircraft the size [and lesser maneuverability] of the Mallard, would it be considered normal flight operations to fly a circuit inside the infield of an airport of these dimensions? I think not - that would be unusual flying. Possible, but unusual.

Perhaps this pilot practiced the turn at a place of similar dimensions, to get used to what most anyone would consider tight maneuvering. I have no idea. I know that water flying can dramatically alter perception of space for maneuvering - it can look like there's room, but there's not that much. This is a major teaching point when I train flying boat pilots.

I train that a water landing is preceded with one or more reconnaissance passes, with consideration for dimensions, the approach, hazards, and the possible affect of wind. I wonder if this pilot had the opportunity to fly some practice or reconnaissance passes before landing.

It is certain that he, as any of us would, maneuvered so as to avoid overflight of crowds or even shore. Once it started going bad, tightening the turn was not going to fix it. He had already run out of room for maneuvering within the normal flying characteristics of that 'plane. I fly light floatplanes and flying boats, and what I see in that video would worry me for maneuvering a light seaplane, let alone the larger Mallard.

I can imagine that this pilot felt pressure to perform with his aircraft, and further would not want to disappoint his passenger. He pressed further into a maneuver than perhaps he had the practice, performance and maneuverability with which to complete it.

The facts will come out, but in the mean time, discussion of what is evident so far can benefit all pilots in reminding that when maneuvering close to the ground/landing in a non aerodrome environment, extra awareness and caution are needed to assure that the required minimum space is available, and that there is an escape plan if the maneuver is going wrong. This video will become an element of my training, with the obvious aspects discussed, even before a formal investigation report is written. Anything we do to make pilots think is good.
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Old 30th Jan 2017, 03:16
  #185 (permalink)  
 
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The "parcel of air" theory is all good and well until that parcel of air gusts, wanes, rises, sinks, sheers, or otherwise changes direction and speed - usually close to the ground. Gravity is a constant. Wind is not. That parcel of air you are moving in can also move around you. A 10kt gust on tailwind loses 10kt over the wing - instantly, and for a brief moment, due to inertia. Your ASI doesn't lie.

The reason for caution turning upwind or downwind (even if that happens to be crosswind) is because that's the direction the wind is likely to gust or drop off - leaving you in the poo if you are low and slow and in a turn losing lift.

We all know this, so I'm not sure why the argument.
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Old 30th Jan 2017, 03:57
  #186 (permalink)  
 
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Well, the 'good' news is that the reason the thing stopped so rapidly is that it hit the bottom; its only a couple of meters deep there so the bodies would have been trapped where they sat, and that will resolve the question.
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Old 30th Jan 2017, 06:29
  #187 (permalink)  
 
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At headmaster et al flat earthers - the earth is rotating at a speed at the equator of about 900 kts. Lucky when when we change direction and walk East to West, our momentum doesn't change by 900 kts worth.


CHANGING DIRECTION WITH A CONSTANT BANK ANGLE IN A CONSTANT AIRMASS DOES NOT CHANGE THE LIFT ON A WING

L= 1/2 CL rho V^2 S

The V in that ole formula is not Groundspeed.
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Old 30th Jan 2017, 07:06
  #188 (permalink)  
 
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If you are too tight, too low and too slow when trying to land whether it be on water or land you will crash. The decision making leading up to it may come from overconfidence or inexperience but physics and gravity will ultimately decide your fate and unfortunately, those seated next to you.
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Old 30th Jan 2017, 07:18
  #189 (permalink)  
 
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The "parcel of air" theory is all good and well until that parcel of air gusts, wanes, rises, sinks, sheers, or otherwise changes direction and speed.....The reason for caution turning upwind or downwind (even if that happens to be crosswind) is because that's the direction the wind is likely to gust or drop off - leaving you in the poo if you are low and slow and in a turn losing lift.
Who in the world would be low and slow and turning? Crop dusters and others who have low level endorsements and are aware of the pitfalls aside. In any case I would assume an aviator would ensure that he keeps airspeed well in hand, and not nibbling on, or close to the stall if low level. Who spends their time in manoeuvring flight below 500'? He/she may well use the "Flight Safety Foundation" recommendations for approach speeds as a basis.

Wind Conditions
The wind correction provides an additional stall margin for airspeed excursions caused by turbulence and wind shear. Depending on aircraft manufacturers and aircraft models, the wind correction is defined using different methods, such as the following:

• Half of the steady headwind component plus the entire gust value, limited to a maximum value (usually 20 knots);
• One-third of the tower-reported average wind velocity or the gust velocity, whichever is higher, limited to a maximum value (usually 15 knots); or,
• A graphical assessment based on the tower-reported wind velocity and wind angle, limited to a maximum value (usually 15 knots).

https://flightsafety.org/wp-content/...-apprspeed.pdf
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Old 30th Jan 2017, 07:36
  #190 (permalink)  
 
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Who in the world would be low and slow and turning?
Glider pilots sometimes do when scratching for low down thermals especially in comps. Circling in a bumpy thermal at 2-300 feet is sometimes necessary to avoid a field landing. Of course the landing field is picked when below 2000 feet just in case the thermal doesn't work!
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Old 30th Jan 2017, 08:28
  #191 (permalink)  
 
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Capt Rex,,

Please read this:

As flyer69 said, I hope none of you preaching the downwind turn being no different are instructors and I hope any prospective pilots reading this don't get it into their heads thinking this.

It might not be relevant to the tragedy in question but there is a reason we try to get as much out of the hopper as possible and make the first turn into wind before having to turn downwind. I reinforced the point to myself after spending 6 weeks in a wheelchair following a downwind turn in which ambition exceeded ability. If you haven't flown a heavy ag plane then you don't know what you don't know.
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Old 30th Jan 2017, 09:16
  #192 (permalink)  
 
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Step Turn
Thank you for your post. No one else seemed to notice but in my opinion it is the most sensible and informative post i have read since the beginning. I have been following this accident report with interest and as others pointed out professional pilots will wait until the investigation is completed before criticising a fellow pilot's actions. I have done many years of outback flying in similar sized twins but thankfully a lot more forgiving then the Mallard which I don't know much about besides listening to others with more experience on type. What I can see on the videos is quiet obvious as to what happenned which has been summed up by Steep Turn and and some other more seasoned pilots.
For now I will sit back and wait for the final report....
RIP P.L. and partner.

Last edited by sms777; 30th Jan 2017 at 09:21. Reason: Spelling error
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Old 30th Jan 2017, 10:01
  #193 (permalink)  
 
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Zac 21 - flown lots of stuff in military low level much heavier than an ag plane at airfield with high elevations and Density alts.

I'm sorry you had a prang, but it wasn't caused by turning into a tailwind. It was caused by you focusing (I'm guessing) on a ground feature and letting the angle of attack increase to the stall point.
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Old 30th Jan 2017, 10:52
  #194 (permalink)  
 
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Originally Posted by ACMS
Is it just me or am I the only one that doesn't want to watch her video.....
I hear ya.
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Old 30th Jan 2017, 10:57
  #195 (permalink)  
 
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This has been done to death before but here goes -

Do your steep turn at altitude - downwind.

Wow - nothing happens.



There is no wild arse stall spin crash scenario awaiting those that try it.

Try it at low level, ignore the ground going past in an unusual fashion - same result.
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Old 30th Jan 2017, 11:01
  #196 (permalink)  
 
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I think this thread has well and truely past its use by date.

RIP to Peter Lynch and his partner. They were both aviation enthusiasts who paid the ultimate price for what they loved!
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Old 30th Jan 2017, 11:03
  #197 (permalink)  
 
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Step Turn - thank you for your lucid, well written and informative piece, with the final sentence saying it all.
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Old 30th Jan 2017, 12:11
  #198 (permalink)  
 
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If a wing/aeroplane "doesn't care about the moving air mass" Why is windshear a big deal?
Could it be that a parcel of air could change its speed or direction faster than a heavy aeroplane can? Does a sailboat instantly travel at the same speed of every wind-gust? Would a light sailboat adopt ambient wind conditions faster than a heavy sailboat? Does a sailor or balloon pilot never feel the "wind in their hair"? (Gust in their hair)
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Old 30th Jan 2017, 12:46
  #199 (permalink)  
 
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Originally Posted by Pastor of Muppets View Post
If a wing/aeroplane "doesn't care about the moving air mass" Why is windshear a big deal?
It cares about the moving air mass - that's what it's flying relative to. If the moving air mass suddenly changes its speed or direction, it cares about that too. It just doesn't care about the Earth, the Sun, the distant parts of the universe, or the fact that you've just flown over SHEED and are turning into a northerly to land at Melbourne.
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Old 30th Jan 2017, 12:52
  #200 (permalink)  
 
Join Date: Jan 2017
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Yup.
If the wind is blowing strong enough, you can fly backwards like a Super Cub can for example.
You can do a 180deg turn no problem. But if the wind died off suddenly, and you were low, well then things could get interesting.
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