20100114026069I

N732VA, a B737-300, part of the initial haiti disaster relief effort carrying fema workers from atlanta to port au prince haiti was given priority descent after an extended ATC delay at FL290 over Toussaint Louverture int (mtpp) for fuel critical handling. After receiving another clearance for FL150 and awaiting further landing clearance for mttp, the aircraft experienced a TCAS resolution advisory (ra) at 15,000 ft MSL which directed the crew to "climb" at 18OO ft per minute indicated. Crew abruptly pitched up and increased power. As a result of the abrupt manuever the aircraft stick shaker came on and the aircraft experienced a pre-stall buffeting, the crew pushed the yoke forward to prevent further buffeting of the wing and pulled up again and continued climb to avoid the traffic, leveling at FL180. During this manuever the flight attendant in the aft cabin struck the ceiling suffering a minor injury. Captain initiated a return to miami (kmia) due to fuel and air traffic concerns. The aircraft was given heading 340 and this time experienced a TCAS traffic advisory (ta) proximity 300 feet. Aircaft was then cleared direct to FL340 (on the O12 radial). On reaching FL340, the cabin altitude warning light illuminated indicating loss of pressurization. The cabin altitude continued to climb despite outflow valve indicating closed and going to manual on pressurization controls. Emergency descent was initiated and the oxygen masks auto deployed at about FL250 while the aircraft was making the emergency decent to 9,000 feet, this was followed by a safe landing at provencialles airport(mbpv), turks and caicos . Company maintenance person on board performed system checks and found no faults with the cabin pressure system. The aircraft was ferried back to kmia at 10,000 feet as a safety precaution on 01/15/2010. Miami company maintenance personnel once again inspected aircraft, performed ground pressurization checks finding no fault and then performed in flight functional check, again with no faults noted in flight and aircraft was returned to service. A secondary pressurization event on the same aircraft occured several flights later on 1/21/2010. Maintenance performed full troubleshooting and ground pressurization checks with no exact cause found. Maintenance performed continuity checks of system wiring, inspected aircraft structure and pressurization related systems and as a precautionary measure replaced the 3 main cabin pressurization system components consisting of the cabin pressurization system controller, the cockpit pressurization overhead control panel and the main outflow valve assembly as well as replacing and securing the insulation blankets as needed in the outflow valve area which were observed to be a possible cause. Maintenance personnel further performed all ground test as per the aircraft maintenance manual requirements followed by an in flight testing at FL370 with no faults indicated. Aircraft was again returned to service.