aparelho de escape variável de motor, motor com turbina a gás de aeronave e método para operar a válvula de escape

A variable bleed valve includes a variable bleed valve door disposed in a bleed inlet in transition duct and rotatable about an axis at or near a forward end of door. Valve is operable to open and close a bleed slot open to a booster bleed flowpath located outwardly of transition duct and having an airflow restrictor. Airflow restrictor may be variable such as a flapper valve. Booster bleed flowpath may pass through a bifurcated bleed duct including an inner passage radially bound by spaced apart inner and middle bleed walls and an outer passage radially bound by middle bleed wall and an outer bleed wall. Airflow restrictor may include an outlet area smaller than an inlet area of inner passage. Door seals against middle bleed wall to open inner passage and against outer bleed wall to open both passages.