Outdated Thrust Reverser Keeps Old Boeing Airliners Flying

The Boeing 737-200's clamshell thrust reverser is an outdated system that has managed to outlive its own logic. Introduced in 1963, it was originally designed for the 727 and then inherited by the 737. The system uses two curved deflector doors that pivot outward and inward to redirect the exhaust jet during landing.

The clamshell reverser only works on the JT8D engine due to its slim design, but it has since been replaced in newer models with more efficient systems. Despite being largely ineffective, the 737-200's clamshell reverser is still found on around 40 airframes that are still in service today.

The reason for this is the aircraft's unique ability to land on gravel strips and short unpaved runways, which no modern airliner can match. The forward-blasting exhaust of the clamshell reverser kicks up vast curtains of gravel as the aircraft slows down, making it an essential feature for operators in remote areas.