When, exactly, were the DC-8’s airbrakes removed?
The DC-8 is equipped with emergency air brake system. This isn't the type of air brakes you might expect on an airplane, but rather on a truck. The captain could pull a handle on the instrument panel to release pressurized air into the hydraulic brake system in the event of hydraulic pressure loss, as explained in this AAIB bulletin. The fuselage air brakes were removed from the first prototype, no DC-8 entered service with them. Although the wing spoilers are not used as speed brakes in flight, reverse thrust is allowed on the inboard engines during descent.