What is a mechanical-blockage thrust reverser?

• A. A thrust reverser that slides a pair of scoop-shaped doors aft and opens them so they block the rearward flow of gases and deflect the gases forward.
• B. A reverser that uses cascades to direct air.
• C. A reverser that vents exhaust to atmosphere.
• D. A system to increase thrust.

Answer: (A)

Mechanical-blockage thrust reversers work by physically blocking the engine’s exhaust path. When deployed, a pair of scoop-shaped doors slides aft into the nozzle opening to create a barrier that stops the normal rearward flow and forces the gas to deflect forward. That forward deflection produces reverse thrust. This differs from reversers that use cascades of vanes to redirect airflow forward or those that vent exhaust to atmosphere without creating a true forward deflection. So the essence is a mechanical blocking of the exhaust to redirect thrust forward.