Boeing’s first 747-8F – RC501 – began flutter testing today from Moses Lake, after being inspected earlier in the week after Boeing and Vought Aircraft Industries discovered defective stringers supplied by a sub-tier supplier.
747-8F begins flutter testing as stringers get inspected (and other 787 items)
The stringers in question are near the aft of the 747′s iconic hump and are mounted on the inside of the aircraft’s skin and run the length of the aircraft. The concern centers around the thickness of the stringer flange, which can crack under certain loads. Boeing says the 747-8F test fleet was inspected earlier this week and cleared for flight, though two program sources I spoke with say that g loading limitations were likely to be in place until the full extent of the defective stringers could be known.
More importantly, aircraft in production are being checked for this similar problem and could prompt a time consuming repair to that would see the stringers removed and replaced.
Meanwhile, RC522 is still carrying out Flaps 30 testing as Boeing continues to identify a permanent solution to eliminate the buffet at the maximum flap setting with the landing gear down.
Additionally, Boeing is studying adding a fourth flight test aircraft to conduct engineering test flights. RC503, the second production aircraft, the fifth 747-8F, the 1424th 747 built is the likely candidate to take part in flight test, though the company says no final decision has been made yet.
On the 787 front, ZA003 and ZA002 are set to rejoin flight test after being in ground tests and layup respectively. Following its post-Victorville maintenance, ZA002 will flight test its new software load this weekend and ZA003 testing will focus on Environmental Control System testing. ZA001 is still progressing through high speed stability & control testing, as the flight test team moves closer to the yet-achieved Type Inspection Authorization, original targeted for February.