An Air Data Test System (ADTS) comprising: at least one pneumatic pump configured to produce an air pressure; at least two pairs of impact and static ADTS ports (120a, 120b, 130a, 130b), one pair of ADTS ports (120a, 120b, 130a, 130b) configured to supply air pressure to a first pitot-static system and the other pair of ADTS ports (120a, 120b, 130a, 130b) configured to supply air pressure to a second pitot-static system; a manifold system in fluid communication with the at least one pneumatic pump and each pair of impact and static ADTS ports (120a, 120b, 130a, 130b), wherein the manifold system includes a channel (CP1, CS1, CP2, CS2) for each of the ports (120a, 120b, 130a, 130b) and further comprises a plurality of pressure sensors (210a -210d) for controlling the pressure in each channel (CP1, CS1, CP2, CS2) and a plurality of zeroing valves (220a - 220d) interposing each channel (CP1, CS1, CP2, CS2), the zeroing valves (220a - 220d) being interconnected and openable to a non-atmospheric threshold pressure prior to commencing a data test for the purpose of eliminating drift in the pressure sensors (210a -210d); a signal processor operatively coupled to the at least one pneumatic pump and the manifold system and configured to issue control signals thereto to test each of the first and second pitot-static systems (12, 14); and a plurality of drop-off valves (230a- 230d) interposing each channel (CP1, CS1, CP2, CS2) and disposed immediately upstream of the static and pitot ports (120a,12b,130a,130b) and downstream of the zeroing valves (230a- 230d) to allow for manual pressure reduction of the applied pressure by sequentially opening in the event of a system failure when power is removed to the ADTS. at least one pneumatic pump configured to produce an air pressure; at least two pairs of impact and static ADTS ports (120a, 120b, 130a, 130b), one pair of ADTS ports (120a, 120b, 130a, 130b) configured to supply air pressure to a first pitot-static system and the other pair of ADTS ports (120a, 120b, 130a, 130b) configured to supply air pressure to a second pitot-static system; a manifold system in fluid communication with the at least one pneumatic pump and each pair of impact and static ADTS ports (120a, 120b, 130a, 130b), wherein the manifold system includes a channel (CP1, CS1, CP2, CS2) for each of the ports (120a, 120b, 130a, 130b) and further comprises a plurality of pressure sensors (210a -210d) for controlling the pressure in each channel (CP1, CS1, CP2, CS2) and a plurality of zeroing valves (220a - 220d) interposing each channel (CP1, CS1, CP2, CS2), the zeroing valves (220a - 220d) being interconnected and openable to a non-atmospheric threshold pressure prior to commencing a data test for the purpose of eliminating drift in the pressure sensors (210a -210d); a signal processor operatively coupled to the at least one pneumatic pump and the manifold system and configured to issue control signals thereto to test each of the first and second pitot-static systems (12, 14); and a plurality of drop-off valves (230a- 230d) interposing each channel (CP1, CS1, CP2, CS2) and disposed immediately upstream of the static and pitot ports (120a,12b,130a,130b) and downstream of the zeroing valves (230a- 230d) to allow for manual pressure reduction of the applied pressure by sequentially opening in the event of a system failure when power is removed to the ADTS.