The David Clark model S1034 PPA was an advanced lightweight full pressure suit which replaced the S1031C (common SR-71/U-2 design) suit and offered significant performance improvements, including enhanced pilot comfort, ease of donning and reduced stress-fatigue. First flown on 20 June 1991, the S1034 PPA was meant to ultimately replace all earlier David Clark S-series suits in use by the US Air Force (which were designed for an approximate 10 year use/life-span). The suit featured integrated life support subsystems to include breathable pressure bladders.