The golden rule is always safety first! So the most important pre-flight task is the security check, where we search for any dangerous or foreign objects on board. It's also the most difficult pre-flight task, as you must bevery careful to check everywhere even though the time is limlimited. A bomb, a toxic liquid, ammunition, or a weapon can be hidden in a very small space. If I find a suspect item, I mustn't touch it. I have to inform the Purser and describe in detail what it looks like and where it is. The Purser informs the Captain and if necessary Aviation Security is called out.