Oil filler tube assembly for aircraft engine

An oil filler assembly for an aircraft engine, comprising:

• a filler tube extending from a bottom end to a top end;
• a valve having a tube side fluidly connected to the filler tube and a tank side fluidly connectable to an oil tank;
• a cap removably secured to the top end of the filler tube;
• a dipstick secured to the cap and extending into the filler tube towards the bottom end;
• and
• a piston secured to the dipstick and sized to be received in the filler tube between the top end and the valve, the piston having:
• a sealing configuration in which the piston sealingly engages the filler tube to fluidly disconnect the top end from the valve, the piston being in the sealing configuration when the cap is secured to the top end of the filler tube;
• and
• a venting configuration in which the piston permits fluid communication between the top end and the valve, the piston being in the venting configuration when the cap is moved away from the top end of the filler tube.