Hnaging by a Thread-Air Crash Investigation

Air Crash Investigation : Season 3 Episode 11.



From this route, we can see the airplane is exposed to the salty and moisture environment increasing the corrosion.



Crash investigation tried to determine how the airplane structure remains in one piece.

The fuselage of the airplane is actually breathing. It would expand at high altitude, and contract at
the ground. That would weaken the structure of the airplane.







Cracks  that is beside the hole of the rivets.

The airplanes were built by many separate panels where they overlapped and bonding together
by gluing (Epoxy). The rivets hold the panel together.

The dark material is the epoxy that used to bond two layers to join together.
The white material is the corrosion damaged area.

The stress tried to pull one skin away from one skin. The stress will go through the bonding not 
through the rivets. The white material is the corrosion area that did not bond the skins together.
Now, the rivets themselves loaded, especially on the top row of rivet. They think to have
fatigue cracking that eventually leading the opening of roof structure. If the epoxy is applied at the exactly right temperature. If the panel is at the moisture or dirt on them that bonding can fail.


Those tiny cracks are difficult to detect.

Evey 10 inches called " Tear Strap "  along the airplane inside the fuselage to strengthen the
structure.

** Ship : Watertight Compartment = Airplane : Tear Strap
      Avoid the damage aggravating.   


If the tear begins, it should only reach to the strap and along 90 degrees angle. Though there is
a hole in the aircraft, it acts like the safety valve.

The purpose of the " Tear Strap "   is to confine any kind of rip to tear in the fuselage skin within
10 inch square.

Preface

Disasters don't just happen, they are the chain of critical events. Unravel the clues and count down for the final seconds from disaster.

Now, using the cutting-edge computer technologies, we reveal exactly what went wrong.
Disasters don't just happen, they're a chain of critical events. Unravel the fatal decisions in those
final " Seconds from Disaster ".

[Highlights]
Bonding Structure. " Epoxy "  :  Moisture, Temperature, Salty... How to choose the epoxy ??
Rivet : Stress Concentration.
Aston Martin DB9 : Using the bonding way to construct the chassis.

[Questions]