Breaking News Feb 03 Air Canada Boeing 767 to make emergency landing at Madrid airport

[J.O.]

I agree it looks like the cap separated. It's likely there's other damage to the under wing / flap areas as well.

[rudder]

The picture of the engine intake forward of the fan blade looks like there was a puncture from the outside.

Perhaps not ingestion from in front of the engine but tire shards and shrapnel from the sidewall of the engine nacelle.

[boestar]

16 hours ago, Don Hudson said:

Hi boestar...not sure what you mean by strange physics. I was thinking of the rotational speed of the wheel at say, Vr, (~160kts?) and the speed of any chunks of retread that were flung away from the carcass out in front of the engine during takeoff and ingested.

Wow, thanks, AAS - now we know why the engine compressor section was "stalling"!

I realize the explosive force of a tire is quite large but the failure mode, generally does not release large amounts of debris.  Its the rotation that tears the tire apart.  in this case the tire is the rear tire on the bogie and the bogie is far aft of the engine.  The trajectory of the debris is whats puzzling.  There is no direct line from A to B.

I have no doubt that this is what happened but an abject will maintain its direction in space unless affected by an outside force.  I want to see HOW it happened.  I am intrigued.

 

[Guest]

Better picture of the damage to the tire. http://www.avherald.com/h?article=4d2d213f&opt=0

[Don Hudson]

2 hours ago, boestar said:

The trajectory of the debris is whats puzzling.  There is no direct line from A to B.

Not an engineer or mathematician!, but I think of the tire as a "pinwheel"...any object that breaks away from an object that is rotating, flies away in a linear track. The round object rotating has an angular speed that is offered to everything attached. If anything detaches, the object doing the breaking away is no longer restricted to going around and its velocity becomes tangential velocity. (for those that want more info....Zzzzzzzz). That speed would essentially be the groundspeed of the aircraft, (about 270fps), minus any resistance such as wind, how clean the break was or any physical objects in the way. 

Non-aerodynamic piece(s) of heavy rubber aren't going to be affected much by the slipstream. They're pretty well free to find a linear path away from the disintegrating tire including just over the front tire, out in front of the local area ahead of the gear & engine into or near the path of the engine and ingested, aided by the intake flow at takeoff thrust.

So the direct line was actually, A to B to C, tire (A), to point of reversal ahead of the engine/wing (B), and (C), ingestion. More than a few pieces of shrapnel were likely ingested but that's for the investigation.

As J.O. has mentioned, the underside of the wing will almost certainly have a lot of damage, (this is how & where the fire on Concorde began - the damage was caused "hydraulically" by the intense pressure on the underside of the wing-enclosed fuel-tank caused by the impact from the disintegrating front left wheels after hitting debris on the runway - this had occurred on previous takeoffs...one at Washington, D.C.).

[Seeker]

30 minutes ago, Don Hudson said:

That speed would essentially be the groundspeed of the aircraft, (about 270fps), minus any resistance such as wind, how clean the break was or any physical objects in the way. 

 

I believe the tangential speed of the top of the wheel to be twice the groundspeed.

[Don Hudson]

Hi seeker - you're right, thanks. It would be 270fps relative to the aircraft but 540fps relative to the runway, roughly.

[JL]

The v shape fracture surface is consistent with running over an object vs cap separation type failures.

[Johnboy]

Not the best quality but a good synopsis of the comms during the incident.

 

[boestar]

Well handled by all involved.

 

[Guest]

[Specs]

On 2/4/2020 at 4:43 PM, seeker said:

I believe the tangential speed of the top of the wheel to be twice the groundspeed.

To validate that - I can attest that when the front wheel of your pickup truck detaches from the wheel hub, you will be able to see the wheel accelerate past you on it's path into the brush.