PA-34 RTO @ YPK-What happened

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pdw
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Re: PA-34 RTO @ YPK-What happened

Post by pdw »

AuxBatOn wrote: Tue Jan 09, 2018 7:22 amI ask you, for the second time at least, what kind of aviation experience do you actually have?
I have the experience that it requires to understand most anything to to with LLWS and smaller fixed wing aircraft, and also how to describe it fairly well. The fact that it might be difficult for an instructor and his/her student to describe an encounter under these conditions .. would not surprise me (maybe the pilots don't even know). So until the facts come forward and successfully challenge this is not the case / or is mainly something else .. I'll continue to polish the surface analysis data for this immediate area to prove (more solidly) as to whether or not .. or what kind of .. LLWS-like air curtrents affected that takeoff at that time at the south end this strong mid-mountain LO.

Lytton and Hope (just noticed the 35kts there).. are the nearest airports to the north and northeast respectively with some useful data in this system .. for how that LO would be affecting air currents/pressures in that lower part of the Fraser Valley over Pitt Meadows.
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GyvAir
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Re: PA-34 RTO @ YPK-What happened

Post by GyvAir »

pdw wrote: Tue Jan 09, 2018 2:40 pm
AuxBatOn wrote: Tue Jan 09, 2018 7:22 amI ask you, for the second time at least, what kind of aviation experience do you actually have?
I have the experience that it requires to understand most anything to to with LLWS and smaller fixed wing aircraft, and also how to describe it fairly well.
pdw wrote: Tue Jan 09, 2018 7:03 am One of the points that is brought up, .. where is the actual anomometer located to sense/record a mid-runway LLWS in progress on this field ?
I would recommend you do a little reading up on how LLWS detection actually works. Remember: always google before you bullshit.
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7ECA
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Re: PA-34 RTO @ YPK-What happened

Post by 7ECA »

Hope and Lytton? Are you friggin' kidding me?

Suffice it to say they botched a rejected takeoff in a Seneca that was likely nowhere near MTOW on a dry runway, in calm winds. They didn't even get off the ground - so to say that some mysterious and fleeting LLWS helped them come to grief, is the stupidest thing I've heard in a long time. And that's saying a lot, for the "bullshitters anonymous" that is aviation.
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AuxBatOn
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Re: PA-34 RTO @ YPK-What happened

Post by AuxBatOn »

pdw wrote: Tue Jan 09, 2018 2:40 pm
I have the experience that it requires to understand most anything to to with LLWS and smaller fixed wing aircraft, and also how to describe it fairly well.
I have no idea what this means concretely. Peehaps you could expand a little? Do you have a PPL? CPL? ATPL? Military?

Do you work in Meteorology?
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Cliff Jumper
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Re: PA-34 RTO @ YPK-What happened

Post by Cliff Jumper »

pdw wrote: Tue Jan 09, 2018 2:40 pm
I have the experience that it requires to understand most anything to to with LLWS and smaller fixed wing aircraft, and also how to describe it fairly well. The fact that it might be difficult for an instructor and his/her student to describe an encounter under these conditions .. would not surprise me (maybe the pilots don't even know).
There are two terrifically interesting things in this response.

Firstly, all of a sudden, PDW now has the ability to type a partially coherent sentence. It's not quite grade school level, but it's light years ahead of his usual written mumbo jumbo.

Secondly, the content of this response is so amazingly delusional... "and also how to describe it fairly well". That is the farthest thing from the truth since Trump said he was a very stable genius.

Given this post shows his ability to use grammar half correctly when necessary, I can only assume that he has in fact been trolling us this whole time (including me, extensively).
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CpnCrunch
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Re: PA-34 RTO @ YPK-What happened

Post by CpnCrunch »

pdw had an accident due to "variable tailwinds on final" years ago, and that's why he brings this up so often. He posted about it a year or two ago.

The CADOR says that they reached flying speed but couldn't get off the ground, so clearly nothing to do with windshear.
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Re: PA-34 RTO @ YPK-What happened

Post by mbav8r »

Cliff Jumper wrote: Tue Jan 09, 2018 2:35 pm Private apiary located near the Baynes/Ford, subgenus APIS - if not cerana. Nearby-Aft flowing leeward convective activity CAN cause agitation and cumulative up drift (lower if not negated). If the crew unfamiliar with installation, (READ lack-of-expectation-bias) considered the sum it may have become apparent that the fore-throttle un-friction slope was declining. THERE WAS NO CHOICE, in split-second forethought to re-stow the aggressor and force-ful transverse asbestos based de-thrust. --No choice--. Seems easy in past view.
Holy crap, cliff jumper is also pdw!
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Re: PA-34 RTO @ YPK-What happened

Post by C.W.E. »

The CADOR says that they reached flying speed but couldn't get off the ground, so clearly nothing to do with windshear.
That does not make any sense at all.

If it had reached flying speed it by definition should have flown.
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Re: PA-34 RTO @ YPK-What happened

Post by AuxBatOn »

C.W.E. wrote: Tue Jan 09, 2018 8:23 pm
The CADOR says that they reached flying speed but couldn't get off the ground, so clearly nothing to do with windshear.
That does not make any sense at all.

If it had reached flying speed it by definition should have flown.
Unless the pitch control power wasn't enough to overcome the inherently downwards pitching moment at rotation speed, which could be caused by a a front-loaded aircraft, incorrect trim setting or something restricting the elevator.

There was an F-18 crash years ago due to an incorrect takeoff stabilator position (4 deg nose down vs 4 deg nose up). It was going far faster than flying speed yet, the control authority available (trim will change your authority in the Hornet) was insuficient to create enough control power on the stabilator to allow the aircraft to rotate.
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Zaibatsu
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Re: PA-34 RTO @ YPK-What happened

Post by Zaibatsu »

There was also a Gulfstream a few years back that tried to take off with the gust locks engaged. It reached flying speed, but could not get airborne.

https://www.ntsb.gov/investigations/Acc ... R1503.aspx

I’d agree that the aircraft was loaded within limits but too far forward for an easy rotation, likely with student, instructor, full fuel. Pitch authority on most Piper aircraft is notoriously anemic.
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Re: PA-34 RTO @ YPK-What happened

Post by C.W.E. »

Unless the pitch control power wasn't enough to overcome the inherently downwards pitching moment at rotation speed, which could be caused by a a front-loaded aircraft, incorrect trim setting or something restricting the elevator.
Yes these could be reasons they rejected but they also are issues that should be very easy to identify.
There was also a Gulfstream a few years back that tried to take off with the gust locks engaged. It reached flying speed, but could not get airborne.
If there were gust locks on the airplane that also should have been quite evident and be in the CADOR wouldn't it?

If the C of G was so nose heavy they could not rotate it to fly why wouldn't they have known that before flight and corrected it?

Or am I being to critical and this accident was not of any real importance safety wise because it was a training event?
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cncpc
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Re: PA-34 RTO @ YPK-What happened

Post by cncpc »

Tried to takeoff with full flaps. Left down after walkaround.

Not saying that happened, but it would produce a similar result.
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Re: PA-34 RTO @ YPK-What happened

Post by Pratt X 3 »

cncpc wrote: Wed Jan 10, 2018 11:03 pm Tried to takeoff with full flaps. Left down after walkaround.

Not saying that happened, but it would produce a similar result.
The Seneca II has the Johnson bar flap handle just like the Cherokee that makes it difficult to get into the left seat with it raised in the full flap position. Not impossible but highly unlikely that the flaps were left fully down.
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pdw
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Re: PA-34 RTO @ YPK-What happened

Post by pdw »

GyvAir wrote: Tue Jan 09, 2018 6:35 pmI would recommend you do a little reading up on how LLWS detection actually works.
It's the vertical one I'd be taking a closer look at, if spending more time on it.
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Re: PA-34 RTO @ YPK-What happened

Post by Cliff Jumper »

pdw wrote: Fri Jan 12, 2018 7:25 am
GyvAir wrote: Tue Jan 09, 2018 6:35 pmI would recommend you do a little reading up on how LLWS detection actually works.
It's the vertical one I'd be taking a closer look at, if spending more time on it.
I concur. Takeoff lane 26L has 0.000452 percentage point slope-down. If the NON-expected pilot not-forethinking the increased height due supplemented bernoulis, although NOT AIRBORNE increased on oleos. The added dimension, between aerofoil and asphalt (read super-height) could translate into VERTICAL SHEAR, although no evident CADORS coverage, certainly the first aspects for TSB would inspect.
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pelmet
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Re: PA-34 RTO @ YPK-What happened

Post by pelmet »

cncpc wrote: Wed Jan 10, 2018 11:03 pm Tried to takeoff with full flaps. Left down after walkaround.

Not saying that happened, but it would produce a similar result.
I don't necessarily agree. I have not flown the Seneca yet but....I did takeoff accidentally with full flaps in a twin Cessna once. The takeoff itself felt perfectly normal. The only difference was that there was no acceleration during the initial climb. A full flap takeoff on the one light twin that I did it on had no effect on the ability to rotate the aircraft.
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Re: PA-34 RTO @ YPK-What happened

Post by Cliff Jumper »

It could be a million things... no?

Control locks, mis-rigged elevator, full down trim, airspeed indicator anomaly, reduced power for whatever reason and didn't recognise until too late, mis-perception (airspeed never really reach Vr), mis-reported (for whatever reason), broken elevator control cable/pushrod/rodend, incorrect VR, overweight, well out of CofG, and so on, and so on.

Or bees.

Have you ever tried to rotate with a cockpit full of bees? No? well trust me, it's difficult.

(full disclosure, I was once involved in an accident that was a direct result of bees. Ever since this time, it has become my personal mission to alert other pilots to the greatest un-talked-about risk in aviation... and that, as we all know, is bees.)
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GyvAir
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Re: PA-34 RTO @ YPK-What happened

Post by GyvAir »

pdw wrote: Fri Jan 12, 2018 7:25 am
GyvAir wrote: Tue Jan 09, 2018 6:35 pmI would recommend you do a little reading up on how LLWS detection actually works.
It's the vertical one I'd be taking a closer look at, if spending more time on it.
Should I even ask... the vertical what?
My gut tells me that you're going to say something like "The vertical component.", which will leave me none the wiser, yet oddly amused.
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pdw
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Re: PA-34 RTO @ YPK-What happened

Post by pdw »

"LLWS detection" .. this would be vertical, as opposed to horizontal llws. Still reading ...
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Re: PA-34 RTO @ YPK-What happened

Post by Diadem »

There was vertical low-level wind shear concentrated exactly at the centre of the runway, that had no effect on the wind detection equipment at the airport, but somehow affected a weather station at a factory miles away. Oh, and it was detectable at the stations in Hope, while is even further away and up a valley, and in Lytton, which is on the other side of a mountain range! Next pdw will be looking at stations in Antarctica to see if there was a westerly flow which could draw a vortex south across the Pacific, thereby causing a layer of air to blow a molecule of dust into the pilot's nose, causing a sneeze at precisely the moment when rotation should have occurred.
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