Servicing Aircraft with Oil

Aircraft oil tanks are normally checked at the same time the fuel tanks are filled. There are few exceptions to this general rule, since some manufactures recommend that the oil level in certain jet engines be checked within a specified time after engine shut down. In all cases, the manufacturer’s instructions should be followed for the specific aircraft not only for servicing procedures but also for type and grade of oil is used.

Aircraft oil tanks should never be filled to capacity or above the labeled full mark on the gage dipstick. This is because oil expands when it becomes hot, and at high altitude it bubbles and expands. The extra space in oil tanks allows for expansion and prevents overflowing. The aircraft’s oil requirements should be checked, and no substitutions should be made for the type of oil to be used unless substitute oils have been approved.