You can start by calculating the Expectation of the amount the insurance will have to pay in the event that something happens to the plane. The answer you get from that expectation is how much the insurance company will "expect" to pay as the cost to insure the plane. Since the insurance company wants to make a $500 profit on average, then that means the insurance company will have to charge the "expected" cost plus an extra $500.

If you need more clarifications, let me know. =D