It's really odd. It's like the fuselage ascended through the rotor disc. A rotor blade strikes the roof of the forward fuselage, buckles mid span then hits the windscreen and separates. Then the rest follows.:sad:

You have to use caution in determining rpm from video, aliasing can produce strange (even static) perceived rpm, as we see often on videos of rotors or props. It may be valid to say theres an rpm change, but whether it's positive or negative or how much is not really possible.

For me the accident sequence is:
- Sudden collective pitch change.
- 1 blade strikes fuselage & departs
- Out of balance rotor over-stresses the shaft and fractures

By private message....a suggestion was made a Swashplate Bearing failure could also be a possible cause for such a tragedy.

Meaning there is a reason they are called "Test Flights"?

The spindle fracture tells a big story.
This was not a repeat of the planetary failure chain of events, as I mentioned earlier, blades stay attached even after powered impact. Look at the tail rotor broom sticks, still attached. The separation is in a completely different spot, not at the conical housing, with struts and all.. No, I would strongly suspect that this started with the blade attachment shown broken in the photo.
fracture surface, even at the view shown, is not a clean shear, it has some jagged features on the aft side, and the area near it is clean from paint.
Then, there is an inward crushed area below and forward. This could be the indication of blade twist overload of the remaining segment of metal.
In this theory, crack exists, and is not detected, rigidity holds the geometry. Initial collective load is a "push" on push rod, blade twists, and crack opens further, BTM (Blade Twisting Moment). Damper loads contribute, possible to be complicit in root cause.
Airspeed increases, transitional lift allows collective to drop. Push rod "pull" begins local crushing, blade now unstable and flutters, before separating from rotor.
main shaft fractures from massive overload.

That was a difficult video to watch. I've never seen that before. I don't wish to see it again. Small mercy it was all over quickly for those aircrew on board. Only thing worse I can think of is the same thing happening from great height.

If we didn't have enough whatching a 225 rotor autorotating alone.....now this. What's the chance to caption that on video?
Anyway, whatever are the causes, I find hard for Airbus to recover from these images. It's more emotional than rational now.
RIP

These kinds of videos are akin to watching a Mid-Air Collision occur.....have seen two of those!

Once seen.....they cannot be un-seen....ever.

One per rev, . I am intrigued by the loss of paint. It is unusual to completely remove paint like this. I am not familiar with this structure, but is there a chance it was bonded at that location?

Blakmax

Maybe, the primer simply didn't stick to the metal and the top coat of paint ripped it off the way it did when the spindle fractured.
Given it was a post maintenance test flight, why would they have needed 6 people on board?

Regardless of the reason for the mainrotor to detach, it's a known fact that Airbus is heavily involved in designing and delivering main components to this aircraft programme.
How many airbus designed rotor disk detachments can be accepted within a relatively short timeframe? Regardless of the root cause, I belive airbus has a MAJOR problem.
The design of this main rotor mast looks very like the 225 mast, but with only four blades. It seems only to have small differences with the drag dampers, de-ice arrangement and dome fairing.
Pitch links, MRH sleeve and blade horns seems identical to the EC225.

This is my take on this accident:

What can cause a pitch link failure? Pitch link damage? Swashplate seizure/failure? Scissor failure?

edit: I also noticed that the pitch link connected to the blade horn of the ruptured sleeve has sheared off at the top, while the other two visible pitch links has sheared off/got the eyebolt pulled out of the pitch link tube at the bottom.

Again Airbus will put the blame on the maintenance crew involved in maintaining the aircraft as usual or they're gonna rule this out as a military prototype crash not in any way related to any other aircraft on the market today. Case closed! :mad:

Rest in peace fellow aviators. :(

Is this the straight 332L2 transmission and rotor system?

It's similar technology. The gearbox integration and rotor system are KAI's design, according to an AH subsidiary.

Correction: the rotor hub is KAI's design.

Spindle wall thickness looks a bit thin.

Surface finish looks a bit bright for paint adhesion.

That's a cheap slap on EC.

Pablo 332. This is my concern as well. I fail to see how paint can fail in this manner. I am a specialist in adhesive bond failure forensics and such a failure in an adhesive bond should ring alarm bells even if it is not a direct cause of the failure. I ask again if any part of that structure is adhesively bonded? If it was bonded then adhesion failures such as that are an extreme warning of exceptionally poor bond strength. If not, then questions must be asked about how paint can just peel off like that. Such a surface finish provides absolutely no environmental protection whatsoever. Adhesion failures in adhesive bonds or paint are indicative of exceptionally poor preparation processes. And before anyone suggests it, a crash event can never change the failure mode in adhesive bonds or paints. The interface is already exceptionally weak and impact can not cause such a change in failure mode.

Regards

Blakmax

Not to be discussed any further here, but my trust in airbus has worn very thin after the 225 accident in Norway.
Can agree that the last assertion is a bit cheap, but the first is a fact from the 225 accident.

Not many similarities with the L2 on this one, more similar to the 225 but with only four blades.
Sleeves, pitchlink, blade horn, droop restrainer support seems by looking at the pictures very similar to the 225.
The sleeves are actually shorter on the this aircraft compared to the 225, if you compare to the photo of the rotor head of the norwegian crash you will see it.
At last it's no doubt where they adopted the design from.

Paint peeling off is not uncommon in this area, at least not on the 225 which by the pictures seems to have used the same paint type, AH replaced this with a glossy light gray color after a while. Maybe they replaced the paint type only for civilian aircraft, I don't know.