Posted by John McHaleMESA, Ariz., 26 May 2010. The fourth Boeing [NYSE:BA] 787 Dreamliner to be built -- ZA004 -- made its first landing at Phoenix-Mesa Gateway Airport this weekend to begin more flight testing.The ZA004 is undergoing a short series of flight tests that require a combination of hot weather and low-altitude conditions. A crew of nearly 75 is supporting the airplane to ensure smooth operations during testing, Boeing officials say. The stay in Arizona is expected to last only a few days.The 787 flight test fleet, currently comprised of four airplanes, has logged more than 820 hours of flying in the last six months. Two more airplanes are expected to join the flight test fleet soon.