How is it possible that 787 is flying icing tests in late August in the skies over Seattle? In fact, Boeing's fifth 787 flight test aircraft - ZA005 (N787FT) - has been been doing exactly that - flying maneuvers to evaluate the handling and stall characteristics as if ice were forming on the 787's wings, horizontal and vertical stabilizers. However, flight test crews aren't out searching for natural icing conditions like they did with ZA001 in mid-May, rather, before taking off from Boeing and
Paine Fields earlier this week, ZA005 was fitted with simulated ice
shapes. Frank Rasor, then director of flight test operations, and now Boeing Commercial Airplanes chief engineer, described the icing tests at a 2009 787 flight test briefing:
Basically what we've done is been able to simulate the worst case icing conditions on the airplane with ice shapes. Flight test is all about the envelope conditions, so we will be testing within that envelope and get ice buildup on the airplane. But the ice shapes allow us to know we are at that end condition, otherwise it's very difficult to measure what's happening on the wing during the flight. It allows us to get there, know the condition, and fly there safely. Ice shapes are primarily foam-epoxy build-up and they're put on with glue and aluminum speed tape that we use in flight tests. They can be taken off. We do performance take-off and landing with those ice shapes on.ZA005 spent a few extra days at Paine Field before the testing got underway on Sunday, after the aircraft developed a hydraulic leak on approach during an August 17 flight from Boeing Field. The aircraft has spent this week flying in and out of Everett and over Puget Sound with the ice shapes fitted to the leading edges of the wings and stabilizers.
A very special thanks to Alex Jossi, who snapped the photo above of ZA005 departing Boeing field on August 17.
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