But if you have just arrived and have no maintenance experience, you must engage in relatively low-level work, such as simple service work, tools, air material collection, etc., which are all related to aircraft maintenance. College students just graduated to do maintenance work from these. They can only do service in the first year, but can't sign, and then they have to pass the promotion examination of the company before they can start to have the right to sign and start to engage in aircraft system inspection and maintenance. Job promotion means higher pay and greater responsibility.