The Test Flight group for the 787 are educating themselves on how to “con” a “smart” airplane. They are gearing up for the first flight sometime in June.
The critical preflight checks will involve using the airplane’s internal power sources, running up the engines and testing the various aircraft systems. The airplane is so innovative that its integration is becoming difficult to test. The hardest part is “fooling” the airplane to “think its flying.”
The 787 uses a distributed electrical system that is designed to be almost completely dependent on software. In the past, the test flight engineers would jump a circuit or write a software change to bypass the safeties placed on a system. An example is a squat switch, that would activate several systems, such as landing gear retraction. Due to the elaborate integration, the Test group is having to come up with creative testing methods.
In recent test, they discovered that the communication between the systems needs to be accounted for. During a gear swing test, the radio altimeter and the engines “talked” to each other, saying “something isn’t right…”
The flight test program is expected to take anywhere form eight and a half months to eleven months. The flight test fleet will consist of six airplanes; four Rolls-Royce Trent 1000’s and two General Electric GEnx-1Bs. These certification tests will have multiple crews flying different airplanes. Usually test airplanes are flown by the same crew.
The test preparation and maintenance will be accomplished during night time hours, while the flying will be done in daylight hours. Test flights are not expected to last more than 5 hours.
The down time is to be minimized by prefabricating the ice shapes for ice testing, the pressure belts for load testing, which usually take 30 days to load will be done in seven.
Other tests to be carried out by non-test fleet aircraft include nautical air mile fuel burn evaluations. The first airplane is going to ANA (All Nippon Airways), which is fuselage number 7. More fuel burn tests will be carried out by fuselage number 20, which is the first major change to a lighter structure.
Flight test for the second airplane (ZA002) will start about three weeks after the first flight. The third airplane (ZA003) is being fitted with a full interior for tests involving system tests and cabin noise. ZA004 will be used for flight load testing and high performance flight. The R-R powered fleet is scheduled to accrue about 2,430 flight hours and the GE aircraft should amass 670 flight hours and some 600 ground test hours.
The 787 will be the first aircraft to meet the new fuel tank flammability rules that came from the crash of TWA 8; it will also be the first transport category airplane needing a lightning protection system, due to its composite manufacture.
The 787 is being tested to ETOPS standards. Boeing’s expectations, at a minimum are for 207 minutes. ETOPS flights are expected to be tested at 330 minutes.
And let's get one thing straight. There's a big difference between a pilot and an aviator. One is a technician; the other is an artist in love with flight. — E. B. Jeppesen
