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-   -   AW169 Rollover (https://www.pprune.org/rotorheads/639524-aw169-rollover.html)

krypton_john 28th Mar 2021 20:13


Originally Posted by ShyTorque (Post 11017852)
Yes, that’s obviously how it started but why no opposite pedal once it began yawing?

Is it yawing because of MR torque or because of TR torque?

[email protected] 28th Mar 2021 21:58


Is it yawing because of MR torque or because of TR torque?
it seems because he put far too much pedal input - he could have lifted to the hover and not crashed the aircraft

ShyTorque 28th Mar 2021 23:30

The blades on the 169 rotate anti-clockwise as seen from above. The tail rotor is on the right of the tail, so it’s a “puller”, rather than a pusher.

It remains to be published whether or not the pilot actually retained control of tail rotor pitch.

If the control linkage failed, as in the Leicester AW169 accident, he may have initiated a yaw only for t/r pitch to run away to full travel. In this case it looks like an uncontrolled amount of positive (power) pedal pitch was involved, rather than the negative pitch that caused the Leicester aircraft to go out of control.

[It used to be part of the RAF Puma conversion course how to learn how “drive” the aircraft forwards out of the situation where the nose wheel had accidentally become fully cocked off to the side. The first part of that recovery was to centralise the yaw pedals to avoid the aircraft rotating uncontrollably, and use the independent main wheel brakes to help stabilise and steer, rather than big bootfulls of pedal. It was important to get this right, due to the high mounted tail rotor the Puma will roll very rapidly and markedly if too much pedal is used on the ground].

Nescafe 29th Mar 2021 01:16

It appears that as the aircraft moves forwards pedal is applied to turn left, so much so that the aircraft actually leans over to the right. The pilot stops forward motion (at 26 seconds), releases the pin and its all over.

jb68321 29th Mar 2021 02:28

So is this just a case of Italian authorities trying to sweep pilot error under the rug? Or did I misunderstand you? Certainly seems like a few pilot errors from my perspective, but I'm not so experienced with AWs. I've heard some stories about the company culture and Italian authorities before though...


The AAIU has already determined it was not the crew’s fault. The pilot was licensed and qualified by the authority and followed the published SOP to the letter, nobody to blame.

SpindleBob 29th Mar 2021 07:40

As said above - That comment about the Italian authorities was just sarcasm - A joke!!

Fair play to the second ground crew - The one furthest from the camera - He was actually running towards the fire extinguisher and still ducking for cover while the aircraft was rolling and showering the ramp in debris. I don't know whether to put him forward for a medal or clip him round the ear!!

Flying Bull 29th Mar 2021 12:14

Hi,
there is a video online on Facebook, where the scenario is replayed in a simulator.
The sim crashes even faster
-R&c[0]=AT2Ip82GROK-OC0FGukaE3KkBck4XtOJ8CVtD75qWZu6FYDWQ4MAKaxkXpxaaZfAPhF5st4a ytG6KQocI7vB23lT0jK1IRlopThWYJCgn7DGmNJ7Ca2W0IG9otSZ68THO5Q0 vpvowzoSGdkwJee0b2Uw-Ba0uyIwd9RxR-GVRrcj3lqa6UMKielU8Lg]Facebook-Link to video

hargreaves99 29th Mar 2021 13:06

it looks like they were trying to taxi and turn left (ie left pedal in) and the nosewheel lock was engaged, when the noseweel lock was taken out, the wheel "flicks" to the left quickly (you can see this in video if you look closely), as a lot of left pedal was already applied the aircraft started to rotate left quite rapidly.

like with any pedal/rotation scenario, once an aircraft has completed one or two 360s the pilot will be so disorientated/surprised/frozen in terror... in most cases it's "game over"

ApolloHeli 29th Mar 2021 13:17

Here's a link to the Facebook video referenced earlier (same scenario replicated in a simulator)

https://imgur.com/a/1DA60zZ

I copied and re-uploaded the video as it was difficult to locate in its original form on Facebook.

gulliBell 29th Mar 2021 19:12

And what does the flashing light on the CWP signify the moment things start to go pear shaped?

Droopy 29th Mar 2021 19:18

That's the nosewheel going through the process of unlocking.

ZAGORFLY 29th Mar 2021 19:33

Incomplete analysis
 
I believe the explanation is incomplete because the pilots would have obviously apply correction rudder right to stop the uncommanded left rotation that let me think that is a hydraulic jam here in place.

[QU=malabo;11017649]The AAIU has already determined it was not the crew’s fault. The pilot was licensed and qualified by the authority and followed the published SOP to the letter, nobody to blame.

But even less seriously...looks like he wanted to taxi to the left, aircraft resisted so he tried a little harder, then remembered the nosewheel lock and when it released the aircraft spun left with full left pedal applied. This threw the pilot to the right still hanging on to the cyclic and collective. So on top of the yaw the pilot has now got the collective coming up and full right cyclic. The aircraft is truly embarrassed at the overreaction by the pilot to the initial slow left turn and rolls over in shame.

fodder for weeks to come on pprune[/QUOTE]

etudiant 29th Mar 2021 20:14

Can only say 'Oh wow!'.
An aircraft in perfect shape, destroyed in seconds because of the nose wheel not being unlocked in time?
If this is representative of the sensitivity of helicopter flying, it explains a lot.
The question that remains is why do very wealthy people accept such low safety standards.

hargreaves99 29th Mar 2021 20:21

unlikely, the fast left yaw would have taken them by surprise and they would have quickly got disorientated


>I believe the explanation is incomplete because the pilots would have obviously apply correction rudder right to stop the uncommanded left rotation that let me think that is a hydraulic jam here in place.

helicrazi 29th Mar 2021 20:26


Originally Posted by etudiant (Post 11018792)
Can only say 'Oh wow!'.
An aircraft in perfect shape, destroyed in seconds because of the nose wheel not being unlocked in time?
If this is representative of the sensitivity of helicopter flying, it explains a lot.
The question that remains is why do very wealthy people accept such low safety standards.

I missed what this has to do with wealthy people?

atakacs 29th Mar 2021 20:28


The question that remains is why do very wealthy people accept such low safety standards.
In this specific case I thnk those guys are supposed to go after the wealthy people (Italian fiscal police )

SpindleBob 29th Mar 2021 20:32

OK, so if we accept that this may well be the cause. Certainly taking out the nose wheel lock with full left pedal, can go very wrong very quickly.

What is the learning? Pilot training? Lift into the hover like ground resonance - Last thing you want to do when you feel like you might have lost tail rotor control, is to get in the air! Perhaps with the violent rotation, your feet might get swept of the pedals?

If this has happened twice by the sound of it, would a software interlock be worthwhile? One that doesn't allow the nose wheel to be unlocked unless the pedals are set at no more than +/- 30% power for example?

helicrazi 29th Mar 2021 20:32


Originally Posted by ZAGORFLY (Post 11018773)
I believe the explanation is incomplete because the pilots would have obviously apply correction rudder right to stop the uncommanded left rotation that let me think that is a hydraulic jam here in place.

This wasnt uncommanded, it was commanded, and as soon as they realised they had forgotten the nosewheel lock and unlocked it (the amber flashing lights in the sim) they got the yaw they commanded.

helicrazi 29th Mar 2021 20:36


Originally Posted by SpindleBob (Post 11018802)
OK, so if we accept that this may well be the cause. Certainly taking out the nose wheel lock with full left pedal, can go very wrong very quickly.

What is the learning? Pilot training? Lift into the hover like ground resonance - Last thing you want to o when you feel like you might have lost tail rotor control, is to get in the air!

If this has happened twice by the sound of it, would a software interlock be worthwhile? One that doesn't allow the nose wheel to be unlocked unless the pedals are set at no more than +/- 30% power for example?

Only 1 aw169 that we know of. It happens on most types, especially puma as detailed earlier.

Pilots are trained, sop's are written, people dont follow them, the cause of many accidents.

etudiant 29th Mar 2021 20:37


Originally Posted by helicrazi (Post 11018797)
I missed what this has to do with wealthy people?

Think recent accidents in Alaska, earlier in France, the Caribbean and before that a UK stadium, all billionaires, wiped out by their helicopters


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