CL-215 down in Greece

[pilotmike]

Originally Posted by 70 Mustang

….pulling the aircraft left ....

To the right.

[cncpc]

Originally Posted by Compton3fox

Juan Browne's Anaylsis of the accident...
https://youtu.be/z6BlaXqmQLA

This is a question for pilots who actually fly this aircraft.
Juan discusses the lack of left rudder input. That is in the context of whether there was an alternate means of picking the right wing up. Juan implies that had the rudder been applied, that might have worked. My question is whether setting up asymmetric power would also have complimented that rudder control input.
I've had occasion to do that in an Aztec years ago in BC, and it saved the aircraft, which was in a delicate situation with a popped Lister latch and some pitch control issues coming from the door being a few inches out into the airflow and blanking the right elevator to some extent. It started to roll on final with the addition of the last notch of flap.

[FullOppositeRudder]

Juan discusses the lack of left rudder input. That is in the context of whether there was an alternate means of picking the right wing up. Juan implies that had the rudder been applied, that might have worked.

I've been wondering the same thing. I'm puzzled by the significant amount of right rudder almost from the time of impact with the tree causing the aircraft to be in a skidding turn. However it's corrected about the time aircraft is in centre of the blue, and you can see the change in excessive yaw almost immediately. Would carrying through to a boot full of left rudder have helped in picking up the right wing? It's unfair to perhaps even ask the question. The startle effect was enormous by this time, they had but a very few seconds to analyse and react where we've had days. And most importantly, we don't know whether the aileron circuit was damaged or restricted by the departure of the float and other possible complications from the tree strike.

One other possible factor returns to haunt me. The wind is coming over the ridge they are turning to avoid. The right wing is possibly still down in 'dirty' and turbulent air, the left wing probably much less so. Indeed it may well be hit with the full force of the air mass as it comes over the top of the ridge. It's hard to comprehend these situations unless you've been down in amongst the rocks as can happen in adventurous ridge soaring. I've seen 15 knots vanish off the ASI in Blanik in a few seconds as we popped over a spur in the main ridge and encountered the resultant curl over. Happily we had around 60 knots at the start, but it's not a nice feeling when it hits you.

My final observation is that it's very hard to pick the variations in terrain from any reasonable altitude. The complexity of the terrain in this situation would not have been fully evident until they were committed to the drop, There may have been a prior pass to evaluate these factors - we just don't know. But it all demonstrates that safe aerial firefighting is a very demanding activity, and experience gained from a long history of low level flying in relatively benign operations ie AG work, is surely a prerequisite for getting down in amongst the smoke, heat and turbulence of direct fire attack, where target fixation cannot be allowed to take over from other complex considerations.

[DaveReidUK]

Originally Posted by Compton3fox

Difficult to see from the video here but the damage looked no worse than the above two incidents. Of course, we don't know what else the L/E Strike may have damaged but based on what I saw during the races, L/Es can take a substantial hit and not render the A/C uncontrollable.

The damage to the L/E visible in the video looks consistent with the effect on the wing structure of the float being violently ripped off. It's worth noting that we can't see the underside of the wing at any point in the video.

[DroneDog]

Original video enhanced and upscaled to 4k plus slow motion & zoom

You Tube

p.s. Don't forget to force Youtube to play the video in its highest quality 2160p, Youtube will sometimes automatically defer to a lower quality.

[fdr]

Originally Posted by DaveReidUK

The damage to the L/E visible in the video looks consistent with the effect on the wing structure of the float being violently ripped off. It's worth noting that we can't see the underside of the wing at any point in the video.

the underside of the wing is not an overly sensitive area to the performance of the wing section, but it is taking tensile loads in normal loading. The LE being damaged, for the span in the images would be a severe impact to section performance, with a very large increase in Cd, reduced AOA for stall, and a reduced CL/AOA slope. The yaw and loss of lift causing additional roll is going to need everything that is in primary and secondary yaw and roll controls to achieve any mitigation, and there is no certainty that it is survivable at all. A P3C Orion overcooked an "overhead set heading" years ago, and blew 3 of 6 D sections off the wings, leaving half the wing with just a flat front face, despite over boosting an overpowered aircraft with 70%+ blown wing, the plane bled off energy rapidly, and lost ~250kts doing a 270 degree turn, and parked in the water in a reef lagoon. The LE controls much of the low speed performance of any airfoil.

If the crew have not had the opportunity to have advanced handling training, a stressful condition of an unexpected emergency with a critical performance and handling issue is challenging. Rudder and asymmetric power may have assisted, the rates look like the derivatives might get close, but the use of asymmetry comes with a compounding drag problem, so performance is going bad in all events.

[Pilot DAR]

the underside of the wing is not an overly sensitive area to the performance of the wing section

I speculate entirely about the damage to the wing resulting from the wing tip float being ripped off (let alone probably the leading edge of the wing also striking the tree). It is possible that when the wing tip float ripped off, it tore skin from the underside of the wing too. It would not take too much ripped wing skin, peeled back and flapping, to cause immense drag, which is well out the wing as well. I cannot speak for the CL215/415, as I do not know it's structure, but I know that other smaller amphibious flying boats are designed such that you can rip off a wingtip float without damaging the wing. I have found this to be true on mine .

In any case, that was a remarkably short time for the crew to reassess the possibility that control might be maintained....

[DaveReidUK]

Originally Posted by Pilot DAR

I speculate entirely about the damage to the wing resulting from the wing tip float being ripped off (let alone probably the leading edge of the wing also striking the tree). It is possible that when the wing tip float ripped off, it tore skin from the underside of the wing too. It would not take too much ripped wing skin, peeled back and flapping, to cause immense drag, which is well out the wing as well.

Yes, that was what I was alluding to as a possibility when the float was ripped off.

[DroneDog]

For those like myself unfamiliar with this aircraft this gves a good idea of he beast.

You Tube

[Mad (Flt) Scientist]

Originally Posted by Pilot DAR

I speculate entirely about the damage to the wing resulting from the wing tip float being ripped off (let alone probably the leading edge of the wing also striking the tree). It is possible that when the wing tip float ripped off, it tore skin from the underside of the wing too. It would not take too much ripped wing skin, peeled back and flapping, to cause immense drag, which is well out the wing as well. I cannot speak for the CL215/415, as I do not know it's structure, but I know that other smaller amphibious flying boats are designed such that you can rip off a wingtip float without damaging the wing. I have found this to be true on mine .

In any case, that was a remarkably short time for the crew to reassess the possibility that control might be maintained....

The upscaled video just above your post seems to show a ragged edge of the leading edge, suggesting that it was indeed damaged as you suggest. That would definitely not aid controllability.

[DaveReidUK]

Originally Posted by DroneDog

For those like myself unfamiliar with this aircraft this gives a good idea of the beast.

Though not entirely representative of the accident aircraft, which was the earlier piston-engined, non-EFIS variant.

[Cedrik]

Originally Posted by DaveReidUK

Though not entirely representative of the accident aircraft, which was the earlier piston-engined, non-EFIS variant.

The aircraft was converted to Turbine power, not a lot different to a 415

[DaveReidUK]

Originally Posted by Cedrik

The aircraft was converted to Turbine power, not a lot different to a 415

No, it wasn't - I challenge you to find a photo of the aircraft in question (1055) with turboprops.

[Liffy 1M]

Originally Posted by Cedrik

The aircraft was converted to Turbine power, not a lot different to a 415

Here is the accident aircraft in 2022:

Flickr Shortlink

[treadigraph]

You can see clearly in the video that it still has radial cowlings.

I don't believe any of Greece's original 215s were converted to turbine 215T standard, they also have some CL-415s in service and Viking/DHC built 515s on order - I should imagine the remaining CL-215s will be disposed of as the new aircraft arrive.

[DaveReidUK]

Interesting article from a few years ago about the issues involved in keeping the older Greek CL-215s flying:

A race against time for Greece’s Canadairs