What is the role of the thrust reverser?

The thrust reverser's primary function is to redirect the engine's thrust forward, which assists in slowing the aircraft during landing. By altering the direction of the exhaust flow, the thrust reverser creates a decelerating force that complements the braking system, making it easier for the aircraft to stop on the runway after touchdown. This mechanism is especially critical during short landings or on wet or slippery runways where additional stopping power is needed.

The other options highlight functions that are not within the thrust reverser's intended use: it does not increase thrust for takeoff, enhance fuel efficiency during flight, or control altitude during descent. Each of these tasks is managed by other systems and components of the aircraft.