Centrifuge man-rating of a conceptual internal abdominal bladder restraint in an extended coverage anti-G suit

An extended coverage anti-G suit, has been demonstrated to improve +Gz tolerance substantially. In some pilots/subjects, however, the abdominal bladder of the anti-G suit may expand excessively upward and inward causing discomfort and pain. This man-rating was performed to evaluate the effects on +Gz protection of an internal abdominal bladder restraint in the Swedish Tactical Flight Combat Suit (TFCS) used in conjunction with pressure breathing during G (PBG). The tests were executed in the Armstrong Laboratory Centrifuge at Brooks AFB with four Swedish test fighter pilots. The centrifuge profiles included gradual onset runs (GOR, relaxed) and rapid onset runs (ROR, with straining), as well as simulated aerial combat maneuver (SACM) runs up to +9 Gz until subjects experienced light loss or fatigue or surpassed 228 s. All subjects withstood 60 s at +9 Gz during GOR and ROR runs with and without abdominal bladder restraint. No difference There was no difference in SACM duration times. In three of four subjects, abdominal pain or discomfort experienced without abdominal bladder restraint disappeared with the addition of a bladder restraint. Ratings of perceived exertion (after 5 peaks at +9 Gz in the SACM), subjective +Gz tolerance, overall comfort, fatigue, and heat stress demonstrated no relevant differences with and without abdominal bladder restraint. Therefore, to enhance comfort, it seems possible to modify the TFCS by adding an abdominal bladder internal restraint without compromising its operational +Gz protection.