Is financial crises precedence for economic crises?

In reality, when the economy is well the banks will be at a profitable situation but when the economy is bad, the banks will be at a loss position and even go bankrupt. Is that not?

NO! Not true! The economy doesn't affect banks in the same manner that it affects businesses in general. It's true that at some point, the economy will affect banks. But it takes a while. How many banks have gone under recently as a result of the poor economy here in America? In general, banks profit for the first couple of years of recession. For example: Interest rates are at all time lows here in America. However banks have long-term assets in the form of loans that were made at much higher interest rates and they are collecting billions on those outstanding debts. The banks put that money in overseas assets that pay higher rates. For example, if the value of the dollar is relatively low, banks will put their money in overseas currencies that pay higher rates.