[vharihar]

https://m.timesofindia.com/world/us/.../104656450.cms

and

https://twitter.com/CitizenFreePres/...9joftntfw&s=19

Is this so simple to happen? I find it hard to believe. I'd have thought the bare weight of an empty aircraft ought to be far more than all the passengers weight combined, so as to render such an incident impossible.

[jkrishnakj]

I always used to wonder why Indigo boards Zone 3 first followed by Zone 1 and then the rest. Now I know why.

Aside, it’s boggling on how this could even happen.

[Jeroen]

Originally Posted by vharihar

Is this so simple to happen? I find it hard to believe. I'd have thought the bare weight of an empty aircraft ought to be far more than all the passengers weight combined, so as to render such an incident impossible.

No, it can happen and has happened numerous times in the past. Some planes are more susceptible to this than others.
Some planes have a special support that can be placed underneath the tail to prevent this from happening.

It is not just the passenger weight, but also the freight and fuel that determines where the centre of gravity will be. In addition there have been cases where a combination of poor weight distribution and heavy winds might make a plane more tail happy.

Pilots are obliged to do a weight and balance calculation prior to each flight. This will ensure the centre of gravity is within predefined limits and also might give information on how to set trim for take off.

But, yes on some planes you do need to be careful on how you load/unload cargo and board/deplane passengers as well.

Jeroen

[vharihar]

Originally Posted by Jeroen

No, it can happen and has happened numerous times in the past. Some planes are more susceptible to this than others.

Could this also be the reason why some tail strikes happen when taking off? Incorrectly set trim I suppose, that doesn't factor in the CG location correctly?

[fhdowntheline]

Usually the T-Tailed planes are more susceptible to this, because of the placement of the engines and the "heavier" T-tail compared to the conventional vertical tail. But this happening to a A321 type is uncommon and that happened during the deboarding. Did the underfloor cargo shift during the flight ? Did they carry extra fuel in the rear which was not used ?

[aviator1101]

Originally Posted by vharihar

Is this so simple to happen? I find it hard to believe. I'd have thought the bare weight of an empty aircraft ought to be far more than all the passengers weight combined, so as to render such an incident impossible.

This phenomenon is called tail sitting. It is quite possible and has happened quite a few times worldwide in the past.

The main cause is incorrect weight distribution leading to shift of fore and aft centre of gravity (CG) outside permissible limits.

Given the differences in the structural design of the various aircraft types, some planes are more at risk of tail sitting than others.

For example, certain stretched aircrafts like the Boeing 737-800 and 737-900 are known to be at increased risk of tail sitting. Hence, the operating airlines adopt more careful loading and unloading procedures or carry an equipment known as a tail stand which supports the tail whilst loading/ unloading.

Originally Posted by fhdowntheline

But this happening to a A321 type is uncommon and that happened during the deboarding.

A321 is the longest in the A320 family of aircrafts making it susceptible to both tail strike and tail sitting incidents. This year itself there have been 4 tail strikes on A321 also.

[pjbiju]

On a lighter note, it looked like the plane got bored and wanted to do a quick take off

On a serious note, if this happens, then I am assuming that the flight might get cancelled until technicians can declare the plane fit to fly again. Is this assumption right?

[itwasntme]

Agree, unusual and I am sure some loadmaster has been sacked for this mishap.

At least it shifted on the ground. I shudder every time I see the Bagram load shifting incident!

https://youtu.be/5fpxm0D46iQ?feature=shared

[arijitkanrar]

Originally Posted by pjbiju

On a lighter note, it looked like the plane got bored and wanted to do a quick take off

On a serious note, if this happens, then I am assuming that the flight might get cancelled until technicians can declare the plane fit to fly again. Is this assumption right?

Yes. Depending on what was the impact when the tail hit the ground, I'd imagine the airframe will be subjected to a full inspection of the fuselage for any cracks or bends.
In addition I guess a pressure test also might be needed.

[Jeroen]

Originally Posted by vharihar

Could this also be the reason why some tail strikes happen when taking off? Incorrectly set trim I suppose, that doesn't factor in the CG location correctly?

Actually, tail,strikes tend to happen more often on landings than take off. Almost always due to pilot error.

Tail strike during take off can be caused during take off due to incorrect balance and weight calculations and or incorrect trim settings. It usually means the plane rotates far more quickly than the pilot expected.

Jeroen

[Rodie09]

If one looks at the side profile of A321 or for that matter any plane, one can make out why such an incident is easily possible. Unlike any other vehicle the rear wheels are almost in the middle of fuselage and may act as a fulcrum and will not do much to support once the weight is tipped to the rear.

Let the picture speak

[vharihar]

Originally Posted by Jeroen

Actually, tail,strikes tend to happen more often on landings than take off. Almost always due to pilot error.

Tail strike during take off can be caused during take off due to incorrect balance and weight calculations and or incorrect trim settings. It usually means the plane rotates far more quickly than the pilot expected.

Jeroen

Thanks. Though I still find it hard to believe that in todays era, sensors and automation haven't able to relieve us of pilot error in these cases (weight, CG position, etc) during take-off and landing. And I'm surprised that we don't hear more of these cases (tail-strikes and tail-sittings), given such a heavy reliance of correct human action for their prevention. I'd imagine they'd be devastating for the airframe's structural integrity.

Also, I increasingly see nowdays in India that rear-half passengers are often asked to disembark from the aircraft onto tarmac from the rear exit (and then take bus to terminal), while front-half passengers use the vestibule (or onto tarmac and bus to terminal). Have seen this in Blore and Delhi. I'd think that these too may involve unduly shifting excess weight to rear of aircraft and can perhaps result in a tail-sitting, if ground crew didnt install a tail-stand.

[binaiks]

Originally Posted by jkrishnakj

I always used to wonder why Indigo boards Zone 3 first followed by Zone 1 and then the rest. Now I know why.

That is because Zone-3 is at the rear end of the aircraft. If they board Zone-1 first, passengers in Zone-2 would find it difficult to get to their seats since passengers of Zone-1 would still be settling. It always makes sense to fill the aircraft from the back to the front when boarding using an aerobridge. Airlines never do that when boarding from a bus - coz, in that case they can use both the boarding doors, and simultaneously fill from both ends.

[Jeroen]

Not for those of a nervous disposition when it comes to flying:

Lots of tail strikes!

https://avherald.com/h?search_term=T...x=0&search.y=0

Jeroen

For those who like to have a little more information on tail strikes.

Here is an interesting article from the Boeing aero magazine series

https://www.boeing.com/commercial/ae...y/tr01txt.html

Enjoy!

Jeroen

[fhdowntheline]

Originally Posted by Rodie09

If one looks at the side profile of A321 or for that matter any plane, one can make out why such an incident is easily possible. Unlike any other vehicle the rear wheels are almost in the middle of fuselage and may act as a fulcrum and will not do much to support once the weight is tipped to the rear.

Let the picture speak

To my eyes at least, it is not a design issue, in fact they could make the A320 stretch to A321 because the plane has taller landing gear, unlike the B737.