As the Engineering Officer (EO) you will be assigned to the Engineering Department and you will be required to follow orders given by your supervisor or those placed in command over you.
Your main responsibility is keeping the Vanguard's systems in running order. These duties will include, but are not limited to; running routine diagnostics, routine maintenance of the ship and all systems, determining the reason for any malfunctions and repairing them. If the Vanguard has docked for repairs you may be called on to assist in repairing battle damage, or even assist in a full refit operation. If an away team or landing party is sent from the Vanguard to a stranded vessel or outpost you may called upon when your specific engineering skills are required for the successful completion of the mission. This may be the building or repairing of Federation or allied installations or vessels. From time to time the Captain may call upon your expertise in determining the best course of action for a given task.
It should be noted that as the EO you are considered one of the best authorities on the Federation's current engineering technology. Keep in mind this will include both it's capabilities and limitations. This entails great responsibility as the Captain may ask you for your opinion on whether the ship or equipment he is using is capable of performing a duty that appears impossible. As the EO it is your duty to the ship, crew and your Captain, to be honest and realistic as to your abilities, as well as the ship or its equipment's capabilities and limitations.