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 »

CWMM is not "irrelevant", no not at all; yet for that kind of runway LLWS far out in the clear it might require a cross refernence for accurate timing if the station had missed it. And I only used the " 50 mile " one to show how many xxxVyyy readings there are elsewhere nearby in that system around that time. Stations north of there had them every hour ...
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rookiepilot
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Re: PA-34 RTO @ YPK-What happened

Post by rookiepilot »

pdw wrote: Mon Jan 08, 2018 2:07 pm CWMM is not "irrelevant", no not at all; yet for that kind of runway LLWS far out in the clear it might require a cross refernence for accurate timing if the station had missed it. And I only used the " 50 mile " one to show how many xxxVyyy readings there are elsewhere nearby in that system around that time. Stations north of there had them every hour ...
LLWS IS reported by stations. Show me one station where that is reported.

Please.
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Re: PA-34 RTO @ YPK-What happened

Post by GyvAir »

pdw wrote: Mon Jan 08, 2018 2:07 pm CWMM is not "irrelevant", no not at all; yet for that kind of runway LLWS far out in the clear it might require a cross refernence for accurate timing if the station had missed it. And I only used the " 50 mile " one to show how many xxxVyyy readings there are elsewhere nearby in that system around that time. Stations north of there had them every hour ...
Look at the wind speeds that went with all those dreaded variable direction winds. The wind was so light most of the day over much of the region that it couldn't decide which way it wasn't going to blow. Not much in the way of gusting reported, either.
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Re: PA-34 RTO @ YPK-What happened

Post by rookiepilot »

GyvAir wrote: Mon Jan 08, 2018 11:52 pm
pdw wrote: Mon Jan 08, 2018 2:07 pm CWMM is not "irrelevant", no not at all; yet for that kind of runway LLWS far out in the clear it might require a cross refernence for accurate timing if the station had missed it. And I only used the " 50 mile " one to show how many xxxVyyy readings there are elsewhere nearby in that system around that time. Stations north of there had them every hour ...
Look at the wind speeds that went with all those dreaded variable direction winds. The wind was so light most of the day over much of the region that it couldn't decide which way it wasn't going to blow. Not much in the way of gusting reported, either.
Where is this low level windshear?
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pdw
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Re: PA-34 RTO @ YPK-What happened

Post by pdw »

Just above (Low Level .. as the naming suggests) except that over any wide open areas like airports, without any obstructions, it drops Lower ... because over flat areas can force cool retreating air out of the way so easily. IMO the timing (YVR 2pm and Abbotford 2-3pm) .. still seems to work for that.

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 ?
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Last edited by pdw on Tue Jan 09, 2018 7:09 am, edited 2 times in total.
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Re: PA-34 RTO @ YPK-What happened

Post by justwork »

PDW is hitting home runs again. Christ.
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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 7:03 am Just above (Low Level .. as the naming suggests) except that over any wide open areas like airports, without any obstructions, it drops Lower ... because over flat areas can force cool retreating air out of the way so easily. IMO the timing (YVR 2pm and Abbotford 2-3pm) .. still seems to work for that.

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 ?
So, there is some obscure LLWS present throughout lower mainland that day but none of the station reported it?

I ask you, for the second time at least, what kind of aviation experience do you actually have?
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Zaibatsu
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Re: PA-34 RTO @ YPK-What happened

Post by Zaibatsu »

LLWS I can deal with. It’s those variable tailwinds that can jump up and bite you.

They did the right thing by aborting. You practically have an inflight emergency every time you take a battered flight school twin into the air in calm winds.
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Re: PA-34 RTO @ YPK-What happened

Post by B208 »

I wonder if C of G played a role. The Seneca is pretty nose heavy with only a student + instructor on board. I remember that we used to put a considerable amount of lead shot in the rear baggage compartment as ballast to compensate for this. Even then, the aircraft took a fair bit of back pressure to rotate.
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Re: PA-34 RTO @ YPK-What happened

Post by Cliff Jumper »

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.
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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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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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