 Uncontrolled oscillations of its wingtip-mounted fuel tank sheared one wing off of an F-104B; this problem was apparent during testing of the XF-104 prototype and was eventually resolved by filling the tank compartments in a specific order.Early F-104s also lacked modulated afterburning, and as a result combat operations could only be performed at one of only two settings, either maximum military power or full afterburner.Effectively this gave the pilot the choice of two level-flight speeds