Toronto place crash 4

[LittleInch]

A Delta plane appears to have touched a wing tip during landing, ripped the wing off then promptly flipped over onto its back.

As they were on the airfield and this time didn't run into anything or catch fire, everyone is alive, though not surprisingly some injuries.

All passengers survive crash landing as plane flips at Toronto airport

Eighteen of the 80 people on board were injured after the Delta plane overturned on landing.

www.bbc.co.uk

This video https://www.dailymail.co.uk/news/article-14407855/delta-plane-crash-toronto-fireball-footage.html makes it look like a very hard landing - no visible flare

 

[GregLocock]

Perhaps David Soucie could explain where the explosive bolts are fitted?

 

[TugboatEng]

The trouble with fusible parts is that they have to be designed to fail near normal operating loads which makes them unreliable and prone to fatigue.

 

[Alistair_Heaton]

Apart from anything else I can't think of any situation that being able to jettison the wings would improve the survival chances.

I certainly wouldn't trust pilots to make the yes no decision on that one.

 

[Alistair_Heaton]

Btw you do have pyrotechnics onboard aircraft. They are used to fire various fire suppression systems and also chemical O2 systems.

Don't ask me how or where they are used. I just know they can be transported and have an exemption from dangerous goods regulations.

 

[LittleInch]

I think (hope) Greg was being sarcastic....

The key area for me now is that connection of the rear spar to the rest of the wing subframe.

That looks like a pretty complex joint and given its location might be rather difficult to inspect on a regular basis.

 

[DirteJoe]

"Transport Canada Civil Aviation(TCCA), which is the aviation authority for Canada, has issued Canadian ADCF–2012–10R1, dated January 22, 2018(referred to after this as the Mandatory Continuing Airworthiness Information,or ‘‘the MCAI’’), to correct an unsafe condition for certain Bombardier, Inc.,Model CL–600–2C10 (Regional Jet Series 700, 701, & 702) airplanes, Model CL–600–2D15 (Regional Jet Series 705)airplanes, Model CL–600–2D24(Regional Jet Series 900) airplanes, andModel CL–600–2E25 (Regional Jet Series1000) airplanes. The MCAI states:

The manufacturer has determined that wing-to-fuselage attachment nuts, part number (P/N) SH670–35635–1, SH670–35440–951, SH670–35440–3, SH670–35635–1, and 95136D–2412, installed at six attachment joint locations, do not conform to the certification design requirements for dual locking features. The nuts are not of the self locking type as required and do not provide the frictional thread interference required to prevent the nut from backing off the bolt. Asa result, only a single locking device, the cotter pin, is provided at these critical joints.In the case where a nut becomes loose, in combination with a missing or broken cotter pin, the attachment bolt at the wing-to fuselage joint could migrate and fall out. Loss of two attachment joints could potentially result in the loss of the wing.

The original version of this [Canadian] AD[which corresponds to FAA AD 2012–22–10]mandated initial and repeat detailed visual inspections (DVIs) of each affected wing-to fuselage attachment joint to ensure that a cotter pin was installed.Design review and analysis of the inspection findings since the original issue of this [Canadian] AD have led us to determine that additional nuts at the forward keel beam joint should also be included in the inspection and that the repetitive inspection of some wing-to-fuselage attachment joints is not required. This [Canadian] AD maintains the initial inspection requirements [for missing or failed (. . .) cotter pins] for six attachment joint locations, and removes the repetitive inspection requirements for all butthe forward keel beam attachment joint. This[Canadian] AD also requires a different repetitive inspection interval, and the[Canadian] AD applicability has been changed for the initial inspection to account for changes made in production."

 

[mfgenggear]

Being observing a lot of mis information on YouTube lately. And on AI
Doing 180 on published information.
I looked up explosive bolts which is common on rockets. I never got involved with wing attachment. Mostly work on fuselage on several aircraft and on the shuttle.
I know it was crazy. Both crazy stuff is happen out there.


AI Overview



+5

Explosive bolts, also known as pyrotechnic fasteners, are used to join components together and then separate them when commanded. They are used in a variety of applications, including space exploration, defense, and marine applications.

Applications

• Space exploration
  Explosive bolts are used to separate rocket stages and hold rockets down to the launch pad.
  
  
• Defense
  Explosive bolts are used to separate solid booster stages and break the mechanical link of a clamp band.
  
  
• Marine applications
  Explosive bolts are used in marine applications where rapid structure separation is required.
  

How they work
Explosive bolts contain an explosive charge that is ignited remotely. The charge breaks the bolt into two or more pieces. The bolts are designed to separate cleanly along a predetermined fracture plane.

Other features
Explosive bolts are available in a wide range of sizes and configurations. They are lighter and more reliable than mechanical latches.

Safety
Explosive bolts are designed to avoid becoming fast-moving space debris. Some pieces that remain attached can serve a secondary function, such as forming part of a reentry vessel's heat shield.


Generative AI is experimental. Learn more

 

[GregLocock]

I was.

 

[Sym P. le]

A suggestion posted on PPRuNe that the aircraft could have been carrying a return trip fuel load, so perhaps 10,000 lbs remaining in the wing upon landing. This weight outboard of the gear would add to the strain on the structural system in a hard landing and be a cause for the right wing to bend down initial contact. I have no experience with fuel loads so just throwing it out there for feedback/discussion.

 

[LittleInch]

Maximum is 20,000, lb so half full or a bit more is certainly possible to save time on turnaround and possibly cost differential at different airports.

Not a huge load compared to max landing weight of 75,000 lb or thereabouts

 

[Sym P. le]

Thanks, I misread the chart. Even so it's worth noting there could have been 3,000 lbs. of fuel in the wing (or what ever the appropriate number might be).

 

[dik]

A suggestion posted on PPRuNe that the aircraft could have been carrying a return trip fuel load

I suspect the amount of fuel would be based on the trip plus safety amount and not on return trip unless the trip was short and fuel prices varied.

 

[LionelHutz]

I wouldn't blame them for not wanting to buy fuel in Toronto but instead carry enough to get back to Minneapolis. I'd expect there is a decent savings there.

 

[Sym P. le]

From the build it video, we can derive the wing/fuselage connections. It's easy to see how the rear fuselage connection can punch out the wing box. (Larger crops attached) Edit: I think I missed two so I revised the drawing but it doesn't seem quite right.

 

[Alistair_Heaton]

The which tank the fuel is in gets a bit complicated sometimes when you have more than the wings.

There is imbalance limits and type dependant requirements for APU and trim and balance sometimes.

Hopefully they will release the flight data with the interim initial report.

 

[Sym P. le]

I put up a new video edit of the landing on Youtube that shows the intensity of the touchdown in Hi Res. A few additional frames, better isolation of the aircraft and stabilized on the horizontal runway axis. It's a jarring 1.2 seconds to say the least.


Youtube

 

[SWComposites]

So what is the point of all this? The airplane hit the ground very hard, then the wing hit the ground, and it broke. Well duh. Wings are NOT sized to sustain an impact with the ground. Period. Maybe we need to wait for the detailed NTSB/TSB report.

 

[mfgenggear]

Well it sparked interest

 

[Sym P. le]

Or we can keep deluding ourselves that the wheels fell off? My initial frame by frame review was of a poor quality video. I thought I would generally see the moment the wing tip buried itself in the ground or the wheel punched through the wing and move on. Instead I found some curious details and dug in a little deeper. I thought I could do better as I learned what to focus on and this was the result. Uploads to the forum are limited as to size and the audience is narrow so I put it on Youtube where it's more suitable. It's rather stunning what a pocket cell phone camera can resolve.

All of the public speculation and analysis pokes around the notions of the wing tip or the landing gear causing the crash. Neither happened, and it was plainly contrary to the balance of publicly available evidence. Perhaps the public discussion will move to the more urgent issue of whether the wing spars are adequately inspected so we can all be assured that another incident isn't just around the corner.

Also, It's not fair for the pilots to be harassed If the aircraft structure was lacking.

To be sure, this seems to have been a very hard landing and the unfortunate result is not a regular occurrence, and yes, I eagerly await the reports. They just can't tell us the wheels fell off.

TLDR:

Wings are NOT sized to sustain an impact with the ground.

The wing did not hit the ground. That's the point.

 

[IRstuff]

Of interest in the video clip is the amount of upward motion of the left wing after landing and the fact that it landed hard on its right gear, which is evidenced by the waggling of both the horizontal stabilizers and the left wing. But, in Le's clip, we can see the left wing dip from the downward momentum, and then immediately flap upwards, when something broke on the RHS of the plane.

I'd say that the right wing itself broke just before the cloud of fuel sprayed out, and the horizontal stabilizer concurrently tilted rightward.