Expendable? I thought the same thing a few years ago before I was
asked to consult on two different VTOL UAVs. The customer was
specifying 6,000 hours Mean Time Between Overhauls and 1 X 10 to the
8th hours Mean Time Between Flight Critical Failures. This is
equivalent to many maned light helicopters. When I questioned the
validity of these requirements I was shown the cost of the sensor
packages these UAVs were to carry. Some sensors were more than the
rest of the airframe including engine.

The only way they could justify the operational cost for these UAVs was
to give up the concept of them being expendable assets,

CTR