Normally, when an engineered product is made, it is undertaken different kinds of tests in the production facility. These products include cars, bikes, and other vehicles on the ground. The stress and failure analyses are all completed within the confines of the factory and the R & D department. Planes, however, are a different case as they have to be made failure proof and we have to be completely certain about it. The cars and bikes, if faced with a problem, can have the part changed or repaired while traveling. A plane can do no such thing as a failure would mean an imminent crash and deaths of hundreds of people. So, it is no surprise that planes are subjected to some intense manufacturing tests in production facilities. But, how much would be the intensity of these tests? These GIFs will give you a good idea.
When a tail strikes the runway surface, you should be alarmed, but not right now. It is merely a test for ascertaining whether the plane’s rear end fails or not. It is also done to find out the minimum take-off speeds as well as the take-off angles. Not all aircraft pass this tough test!
Then you land the bulky aircraft in a pool of water to perform the spray tests. The engines and body are indeed waterproof, but you don’t want them to be damaged by the debris from the runway. This debris may mix up with the spray to cause massive damage while getting stuck in between.
Here is what happens to the wheels when you try to brake the aircraft just before the take-off speed. It is common for the tires to catch fire and they do so in this case as well. Still, firefighters are invited to the site after five minutes of this fire to find out how good it can respond to such a situation.
There is a reason why some airplane wings bend but do not snap. These wings are tested to withstand 150% of the designed load before breaking. Here is what happens to the wings that don’t meet the requirements.
Here is what happens to an engine when an engine blade detaches. These tests are meant to show that the engine assembly can have these parts inside to reduce the damage caused by venturing outside.
Here are the blades falling apart from the assembly.
So you see, the airliners are quite safe. This is a reason why you are more likely to be hurt in a car accident than in an airliner crash!