Originally Posted by
Winemaker
Isn't most of the flight testing done out of Moses Lake?
Experimental Flight Testing is usually based out of Boeing Field - that's where all the offices, crew, equipment, etc. are located, although there are exceptions.
That being said, much of the actual flight testing occurs at and around Moses Lake. Very common to takeoff out of Boeing Field and head for Moses Lake to do the actual flight testing - not only a relatively unused airport, the airspace is far less crowded than it is around the Puget Sound area (the other common area was to head over the Pacific west of Washington/Oregon to get large, open blocks of airspace - useful for things like drag and fuel burn testing, where you need to fly straight, level, and hands-off for minutes at a time).
When we were flight testing the 747-8, it was right in the middle of the 787 flight test program. Boeing Field wasn't readily able to support both flight test programs at the same time, so they relocated the 747-8 flight testing to Victorville for a while. It worked, but it was very expensive to keep the over a hundred person crew remote for an extended period.