A gas turbine engine comprising: a fan drive turbine for driving a gear reduction, said gear reduction for driving a fan rotor; and a lubrication system for supplying oil to said gear reduction, the lubrication system including an oil tank (90,126), a deaerator (88,124); and a lubricant pump supplying an air/oil mixture to an inlet of the deaerator (88,124) characterised in that: the lubrication system further comprises a pipe outwardly of the oil tank (90,126), wherein the pipe connects the deaerator (88,124) with an inlet within the oil tank (90,126); said deaerator includes an air outlet and said oil tank (90,126) includes an air exit; the lubrication system further being characterised in that it is configured to: separate oil and air; deliver separated air to the air outlet; and deliver separated oil into the oil tank, wherein said separated oil is first delivered into the pipe outwardly of the oil tank, and then into a location beneath a minimum oil level in the oil tank, and air within the oil tank moves outwardly through an air exit to reenter the deaerator, and leaves the deaerator via the air outlet. a fan drive turbine for driving a gear reduction, said gear reduction for driving a fan rotor; and a lubrication system for supplying oil to said gear reduction, the lubrication system including an oil tank (90,126), a deaerator (88,124); and a lubricant pump supplying an air/oil mixture to an inlet of the deaerator (88,124) characterised in that: the lubrication system further comprises a pipe outwardly of the oil tank (90,126), wherein the pipe connects the deaerator (88,124) with an inlet within the oil tank (90,126); said deaerator includes an air outlet and said oil tank (90,126) includes an air exit; the lubrication system further being characterised in that it is configured to: separate oil and air; deliver separated air to the air outlet; and deliver separated oil into the oil tank, wherein said separated oil is first delivered into the pipe outwardly of the oil tank, and then into a location beneath a minimum oil level in the oil tank, and air within the oil tank moves outwardly through an air exit to reenter the deaerator, and leaves the deaerator via the air outlet. the lubrication system further comprises a pipe outwardly of the oil tank (90,126), wherein the pipe connects the deaerator (88,124) with an inlet within the oil tank (90,126); said deaerator includes an air outlet and said oil tank (90,126) includes an air exit; the lubrication system further being characterised in that it is configured to: separate oil and air; deliver separated air to the air outlet; and deliver separated oil into the oil tank, wherein said separated oil is first delivered into the pipe outwardly of the oil tank, and then into a location beneath a minimum oil level in the oil tank, and air within the oil tank moves outwardly through an air exit to reenter the deaerator, and leaves the deaerator via the air outlet. separate oil and air; deliver separated air to the air outlet; and deliver separated oil into the oil tank, wherein said separated oil is first delivered into the pipe outwardly of the oil tank, and then into a location beneath a minimum oil level in the oil tank, and air within the oil tank moves outwardly through an air exit to reenter the deaerator, and leaves the deaerator via the air outlet.