Crash

A Crash occurs when an aircraft experiences more force than it can handle. When the aircraft crashes, it breaks into many parts and a shattering sound plays for about 3 seconds. The broken fragments can destroy another aircraft if it collides with it hard enough.

Ways to crash
There are many ways to destroy your plane.

Ground impact
Most crashes are caused by hitting the ground too hard, or hitting terrain at high speed. Other causes include landing on rough terrain and hitting roads.

Water impact
This is another common cause of crashing. Landing on water at a speed of 50 or more will result in a crash.

Structure impact
Hitting bridges, buildings, and roads will also destroy your aircraft. Since structures are easy to avoid, deliberately crashing your plane into them is the most common way to destroy your plane with objects.

Robot
This is an extremely common way to crash because the robot is hard to avoid, try flying higher to avoid hitting a robot, or shoot it to deactivate it.

Payload
Making extreme maneuvers while carrying more than two items can cause your plane to break apart mid-air. When carrying a heavy payload, make gentle movements and try not to use full power, even with the jumbo aircraft.

Ramp
Taking off with the ramp open is a very easy way to crash. The only way to take off with the ramp open is by letting the speed lift the plane. Landing with an open ramp is almost impossible.

Aircraft collision
Although often caused deliberately, this can unintentionally happen when trying to fly together or do a close flight. Even hitting plane fragments can destroy your plane.

Vehicles
Because vehicles are indestructible, entering a plane too fast will break it, or deliberately crashing your car into it.

Gun
Shooting your plane will break it, on ground and mid-air. A plane can withstand 10 shots before it breaks.

Tailstrike
Rotating the aircraft when the speed is far below 40 can cause the tail to hit the ground, and the aircraft to thus crash.

Trivia

 * Sometimes the crash sound is played multiple times at once, making it sound glitchy.