In addition, hydraulically-operated triangular air brakes were installed on the rear fuselage, which worked in addition to the existing 'finger'-type brakes installed in the wings; the new brakes gave the pilots a greater level of controllability, improving the accuracy of low-level bombing runs. The B-57B was equipped with an APW-11 Bombing Air Radar Guidance System for target approach guidance, as well as an APS-54 radar warning receiver. The engines were also furnished with a new cartridge starting system, eliminating the reliance on ground start carts.