Gas turbine engine having slim-line nacelle

A gas turbine engine method, comprising:

• sensing an operability condition;
• increasing a discharge airflow area of a variable area fan nozzle;
• and
• introducing an airflow at a surface of a nacelle assembly, wherein the steps of increasing and introducing are performed in response to the operability condition from the sensing step.

A method of designing a gas turbine engine, comprising:

• providing a nacelle assembly that includes an inlet lip section and an inlet internal diffuser section downstream of the inlet lip section;
• positioning a variable area fan nozzle near an aft segment of the nacelle assembly, the variable area fan nozzle adaptable to move between a first position having a first discharge airflow area and a second position having a second discharge airflow area greater than the first discharge airflow area;
• positioning at least one boundary layer control device near one of the inlet lip section and the inlet internal diffuser section;
• and
• moving the variable area fan nozzle from the first position to the second position and actuating the at least one boundary layer control device to introduce an airflow in response to an operability condition.

A gas turbine engine, comprising:

• a nacelle assembly that includes an inlet lip section and an inlet internal diffuser section downstream of said inlet lip section;
• a variable area fan nozzle positioned adjacent an aftmost segment of said nacelle, said variable area fan nozzle configured to move between a first position having a first discharge airflow area and a second position having a second discharge airflow area greater than said first discharge airflow area;
• a sensor configured to detect a windmilling condition of said gas turbine engine;
• and
• a controller configured to command movement of said variable area fan nozzle from said first position to said second position in response to the detection of said windmilling condition.