TBM Gear collapse on take off

[pdw]

The only way it wants to go over left if there's more power on than normal and yet pulls it off at rotation like the normal expectation (of a performance increasing with height) but with also now the 'less lift than normal' of the ground contam ... and if it's instead catching up with more tailwind right there he's gotta keep 'head down' a bit longer right there ... and got TOO slow because of contamination which he was said he was watching ("sloughing off").

Not expecting that extra slowing .. so it takes by surprise... that's all I'm saying; he survives because it's not stalled yet ... but IMO freaks out the pilot ... so voluntartily puts it back down exactly as stated there (report)

[Cliff Jumper]

He's not expecting that extra slowing .. so it takes by surprise... that's all I'm saying; he survives because it's not stalled yet ... but freaks him out .. voluntartily puts it back down as stated

So, he was "surprised' by the 'extra' couple of knots (or fpms) of "slowing" and so he put it back down???

No.

Simply, no.

[Cliff Jumper]

I'm sure you're correct, and I enjoy pdw's contributions as much as anyone.
It's still true that low level wind shear has caused numerous aircraft more capable than a TBM to crash.

Well, now you're changing the story. LLWS is not a normal gradient.

Secondly, I'm not sure that the statement you've made is correct. What aircraft is 'more capable' at combating LLWS on departure than a TBM. A TBM is a light weight/low inertia high powered, quick accelerating aircraft.

I would very interested to read about the 'numerous' crashes which have occurred with aircraft of this type during LLWS on departure.

[pdw]

Pilot said it was "stalling" (could feel it) .. to me that meant 'not yet stalled' ... so then PUT the nose down power off .. that probably means the pilot is already thinking "down" is happening anyway. Is it the extra P- factor that forces this descision ? No hdwnd but tlwnd increasing with height ... so more fuel/power/thrust/enerby blown thru the prop to get at that elevated groundspeed to achieve airspeed in the first place [where the patience to pull off more gradual wouldn't be a routine to think of (in that sense allowing it into rotation prematurely already .. may be part of the difficulty encountered)].

Lift loss from increase tailwind AND attached precip narrows the two sided stallspeed margin (the former skims off the top of it and the ice undermines it from the bottom of the narrowing margin) which is the total effect the SLOWING-event had on the immediate Airspeed when realized. It's firstly the amount of increase in tailwind during the roll (even just 2-3kts here), secondly the fact that it's increase-tailwind not increase-headwind (felt heavily/suddenly when coming up out of ground effect to the "150ft"), and the fact of the extra power making those 20kts faster at rotation (in every case twice the difference than against the current). The power going on there gets threatening with yaw already ... so dropping that power avoids it (so IMO it would be accurate to say "felt it stalling").

In this case the tailwind reported in the final happens to be as close to 100% as can be. As said before, the tailwind given there is 010True and take-off direction is 180True. Not often you see an example perfectly like that.

[pdw]

The following is not from the final (unless I missed it):

"Prior to this segment, the aircraft had departed from Vancouver/Boundary Bay, BC (CZBB) and was observed on radar to deviate from cleared altitude several times on the departure, as well as on the approach to KBLI. The pilot reported to the FAA that they experienced auto-pilot issues".

CZBB is 40nm NW from KBLI. Can check for "LL WS" within previous hour/wx-hist along the TBM's Low Level repositioning route. Also seeing there's more to this icing, if a catch base still there from a previous leg.

[Canoehead]

pdw

The airplane crashed because the wings were contaminated and they stalled. End of story. An 8 knot tailwind did not play into it, nor did a "shear".
"Extra thrust" is just bafflegarb. Not sure where you saw anything about a decreasing performance shear, or "extra thrust" in the report.

If it was a contributing factor, the NTSB would have included it in their report.

Airplanes routinely takeoff and land with tailwinds. It's not dangerous if the pilot follows the airframe manufacturers procedures and adheres to the airframe (and pilot's own) limitations. This guy failed step #1- clean aircraft concept. Everything else is you say are moot points (and even incorrect in at least one instance). If you want to dissect this, why not discuss the real issue?

[170 to xray]

Some of you have renewed my faith in Canadian aviation. I am shocked that a pilot doesn't deice/antice, stalls on takeoff and some people are concerned about the effects of an 8 kt tailwind.

PDW, if you beleive the airplane was not yet stalled....what do you think of the pilot's corrective action to an airplane that hadn't yet stalled?

[pdw]

The pilot was quoted as saying he noticed it was stalling so he put the nose down. He admitted he should have de-iced better. The plane is from Manitoba where its mostly plains. So here's something interesting: A guy flies south from the land of icing where he's quite familiar is often bad (icewise) ... gets into trouble ... and has to admit he could have de-iced better. The safeteyboard that deals with the aftermath from the sunshine state to Hawaii has to tell its population of pilots again to watch out (their "mandate"). Must know about "clean concept" esp if you're from FL or Hawaii (non ground-icing places)and might not have as much clue what ground icing is about.

The pilot admits it, yet IMO let us pause for a moment and not too hastily overlook at what happens around mountainous terrain (or at least the Hills around Bellingham) that might be foreign to the accident equation for his perspective. A few nautical miles off the right wingtip at the time of the accident the sunny shores station "KWAFERND4" south of Neptune Beach WA (7NM West of KBLI) gusted 33.3kph (18kts NNE) at the time of this takeoff (7-8NM due west of BLI). Others evidence 13-15kts NNE at the time, with readings every few minutes making it possible to track better. At Bellingham it's halfway between the hourly metar which is ~ 30 minutes before and after the take-off (then no accelerating component recorded in there).

[Canoehead]

I don't care if he took off with 20 knots of tailwind. It's not the reason the airplane fell out of the sky. Not even remotely.

Drop the wind thing already.

[pdw]

-

[pdw]

It's component change as it affected this performance; I'll never mention the W word except the amounts from station reference. Anyways, it could have been nearly "20" well above the runway from what I've gathered ... so half that .. 10kts of actual shear .. would that make a difference ? But I doubt it was quite that much (still checking). With a higher stallspeed now (ground ice) and the OTHER, the groundspeed had to be up mighty quick & high and still accelerating with great power on (for all that extra energy the airframe now requires).

...and so he put it back down?

Considering the longer take-off run required was all over very shortly from "150ft", which hints IMO that the stalling reference means running out of right rudder effectiveness (photo/video/location looks like a left turn made) so that 'cutting power' became necessary to stay straight, no other option.

With at least 30% less lift already given by an icing verdict, the extra AIRspeed / performance loss (of any amount) has exponetially greater effect than under "clean" circumstances. Pilots (getting away with ice before) reading, and not picking up about the OTHER performance loss, can't equate that their better air might have helped survival in those past breaches. We can automatically think case-is-closed / this plane must have been covered in ice from nose to tail (ie 'that idiot' quote/unquote) and go away unchanged, thinking that will never happen to me.

[mbav8r]

pdw, you obviously have thick skin, you've had this fixation on wind and it's level of contribution to just about every accident mentioned(exaggeration?, maybe, maybe not), however this accident would NOT have happened if the wing was clean, whether it wouldn't have happened if there was less tailwind, shear, no shear is frankly irrelevant!
If this TBM ended up in the exact same spot because of an engine failure, the only part the wind would have played is how far he went sliding down the apron.
I will give you one thing, a 10kt shear if it was present could have affected stall speed but I can almost certainly guarantee another thing, this pilot knowing his wing was not fully clean would've rotated at a higher than normal Vr, so everything is a factor including how heavy the aircraft was(size of his morning bowel movement), the reason nothing else is mentioned is, this was happening regardless.

[pdw]

... can almost certainly guarantee another thing, this pilot knowing his wing was not fully clean would've rotated at a higher than normal Vr, so everything is a factor including how heavy the aircraft was ...

That's calling it (more than likely right on). Yes a pilot doing this might have compensated with "higher than normal Vr" knowingly, when already keeping the eye on "sloughing off" where counting on the loosening catch (a slushy precip/texture) if that was the idea. So then lets quickly add this up: With the "higher than normal Vr" the runwayspeed gets faster (1) when deploying more power in "tailwind" departure which is maybe counted upon (but also is not mentioned in this report whether-or-not aware nor if an actual/proposed strength is made available at BLI-wx station in sequence with the precise accident departure timing).

The big reason for higher power setting/needed/used then (if "higher than normal Vr" already) .. which IS counted upon ... obviously is the NTSB's residual ground icing finding [aiming higher for any texture that might have been in process of forming/holding-on (ie: just in case substrates WERE NOT releasing quite as planned in the available slipstream)]. (2)

(3) Only on top of these other two could a more obscure 'LLWS finding' even matter at all (which might have only subracted IAS in that smaller way I'm now imagining, thanks to Justwork); yes, if stumbling the airspeed indicator's increase to that stronger dreamed-of AS that was expected (however little it falters right then .. but then altogether with 1,2 &3) the pilot wouldn't have remotely anticipated the escalating Vr necessary there than perhaps was the lesser precautionary estimate executed, thus 'safe to say' [/i]would NOT have been counted on (#3 pending the acceptance of the wx-hist evidence available for proving its existence; kwafernd4,kwafernd43&kwafernd7 for starters ~noon feb27/17).

[Cliff Jumper]

... can almost certainly guarantee another thing, this pilot knowing his wing was not fully clean would've rotated at a higher than normal Vr, so everything is a factor including how heavy the aircraft was ...

That's calling it (more than likely right on). Yes a pilot doing this might have compensated with "higher than normal Vr" knowingly, when already keeping the eye on "sloughing off" where counting on the loosening catch (a slushy precip/texture) if that was the idea. So then lets quickly add this up: With the "higher than normal Vr" the runwayspeed gets faster (1) when deploying more power in "tailwind" departure which is maybe counted upon (but also is not mentioned in this report whether-or-not aware nor if an actual/proposed strength is made available at BLI-wx station in sequence with the precise accident departure timing).

The big reason for higher power setting/needed/used then (if "higher than normal Vr" already) .. which IS counted upon ... obviously is the NTSB's residual ground icing finding [aiming higher for any texture that might have been in process of forming/holding-on (ie: just in case substrates WERE NOT releasing quite as planned in the available slipstream)]. (2)

(3) Only on top of these other two could a more obscure 'LLWS finding' even matter at all (which might have only subracted IAS in that smaller way I'm now imagining, thanks to Justwork); yes, if stumbling the airspeed indicator's increase to that stronger dreamed-of AS that was expected (however little it falters right then .. but then altogether with 1,2 &3) the pilot wouldn't have remotely anticipated the escalating Vr necessary there than perhaps was the lesser precautionary estimate executed, thus 'safe to say' [/i]would NOT have been counted on (#3 pending the acceptance of the wx-hist evidence available for proving its existence; kwafernd4,kwafernd43&kwafernd7 for starters ~noon feb27/17).

PDW, I'm not intending to be a jerk, but I genuinely think you should print out your last post and take it to your family doctor.

Say "I wrote this, and I think it makes sense."

Perhaps he can get you some assistance.

If I'm wrong (we're wrong), what's the harm?

[CpnCrunch]

Classic PDW! This should go in the avcanada hall of fame.

[Canoehead]

pdw

What do you mean by your reference to "higher power setting"? Do you think TBM's take off at FLEX (reduced) power?
I honestly am confused by your perception of what this airplane went through. It was not the launch of a Space Shuttle, nor a space X rocket.

Wind had Z E R O to to with it. Honestly I bet 30 knots or more wouldn't have any affect on what happened.

Wing(s) stalled due to contamination. That's it.

[pdw]

We agree on contamination, the way that it is presented in this report.

Do you think TBM's take off at FLEX (reduced) power?

If on purpose taking off the opposite direction and with the ground icing (where taking off against the current is always the recommended direction) I "think" the TBM's power was already at top power setting when barelling down rwy16 ... whatever combination worked the best for that / or is permitted (as a max).
________________________

KwaBelli71 station East of rwy16/180T registers ESE before take-off. Appears sustained NE/NNE picks up strongly right at departure time except where taxiing for take-off rwy-16 downwind & lee of the forest at NE corner of airport lands / near threshold. Tree stands beside runways mainly block crosswind components, but here could mask the "tailwind" (that proves to be increasing at the time) at the launchpoint; if choosing wrong rwy-direction say if 'at own discretion', it could be just an error made ... with BLI wx-station at opposite side of field, the SW corner. This report provides the only metar from there that is recorded "27 min" prior to departure.
__________________________

If you want to dissect this, why not discuss the real issue ?

Like for instance tailplane ice, where a tail stalls up/out of download ? Couldn't make out in the accident photo/video if there was flap deployed.

[justwork]

I just want PDW to know I took off with a 7kt tail wind today. By 400' it was about 30. I was neither shocked nor surprised, and the airplane suffered no noticeable loss of performance. And I lived.

[pilotsmack89]

I feel like this was an episode Mythbusters did... if not, it's equally as silly.

Tailwinds make lower speeds a little squirrelly, yes. However the big problem with them, especially with such a small tailwind, is that it increases takeoff distance. Once the plane rotates and takes flight, the tailwind doesn't matter anymore. You see, the aircraft has separated from the earth and is now at the mercy of the little bubble of air it is in, and if that bubble is pushing the plane forward and making it go faster, that won't scare the plane into not flying.

The ice on the wing however....

[pdw]

Actually that's just the point, it's not established in the new air bubble yet ... is it?

squirelly

Esp when it cuts into the major-enough increasing of tailcomponent from over those trees with contam. Airframe airspeed stumbles in process of attaching to the unusual "bubble" above (renewed bursts of increasing / slightly-left tailquartering) just barely out of ground effect at contam-stallspeed.

... and the airplane suffered no noticeable loss of performance.

That's it, when goes un-noticed for any length of time going in; with ground-ice/ICE it has vulnerability to airspeed drop at the risen (ice) stallspeed much much sooner. Not expecting it, is the secondary factor to consider with that ...

[goingnowherefast]

Lets agree for pdw's sake that the tailwind played a 0.5% factor in this accident. The remaining 99.5% was contamination.

[mbav8r]

So what I'm getting, if you want to take off with a contaminated wing, do so into wind, is that pretty much it t?

[trey kule]

So what I'm getting, if you want to take off with a contaminated wing, do so into wind, is that pretty much it t?

Wise words....you have learned the lesson well.

[pdw]

Can't agree more that it is "wise" (to pay attention to the early lessons about the windsock).

So what I'm getting, if you want to take off with a contaminated wing, do so into wind, is that pretty much it ?

"What I'm getting" is that the contamination-weather more often has the uncertain components; but if you "want" to ask it that way ...

... here was not an applicable ATIS component (seeing it's dated 1/2 hour before/after crash; report). Some of the 10 minute kwabelli's display "ESE" briefly (SE of this airport area). Just saying .. that knowing for sure whether "into" or not might get somewhat deceptive in certain wx signatures, and that should add to a wariness against ever defying "clean concept" in any way.

ie: Here on rwy16 it's no question a rise in tail-component along the rwy and up thru ground effect, just showing a light and variable sock lee of trees and the aerodrome-wx at that point is still a mile further along.

So "you want to" know when you're "contaminated", to be able to do what it takes for "clean concept". Nobody wants to take off with a contaminated wing.

EDIT: (For some gramatical errors .. sorry about that, it got real tire-some trying to explain what I felt was far less complicated to explain as it turned out to be)

[GyvAir]

I can't bring myself to read your posts anymore, pdw.