Are engines fed differently in reduced gravity aircraft? Reduced gravity aircraft are basically airliners without passengers seats. As airliners, those aircraft were not designed to fly for a long time in zero-G. Specifically engines were not designed to be fed with fuel for several tenth of seconds in reduced gravity conditions. I'm aware that aerobatic aircraft are equipped with devices to feed the engine in negative-G conditions for a limited amount of time, but what about the reduced gravity aircraft?

EDIT: aerobatics aircraft are equipped with header tanks and/or flop tube able to get fuel in tank even if flying inverted (e.g. flop tube's end goes to the bottom of the tank, bottom defined in Earth frame of reference, whatever the attitude of the airplane). This design allow pipes to always be inside the liquid fuel of the fuel tank, and thus pumps can do there job (pump liquid). But when in zero G, liquid is no longer attracted toward one side of the tank (either the bottom or other side) and thus pipes may be fed with a mix of air (or whatever gas or vapor that is inside the fuel tank) and liquid fuel. Pressurized tanks do not change this. Yet, engine must be fed in fuel for several tenth of seconds in those condition, and I doubt fuel contained in pipes can last more than few seconds. Devices to fed a reduced gravity aircraft's engine should be different from the one in aerobatics in at least two way:


aerobatics are designed to operate in inverted flight (not zero-G) and are in zero-G condition for a small amount of time (less than a couple of aerobatic maneuvers before being again in normal or inverted flight)
reduced gravity aircraft are airliners (may be modified, but how?)
Zero 'g' aircraft are basically commercial aircraft. 

In general, it is mainly the fluid systems like the fuel and hydraulic systems in the aircraft which are affected by the zero gravity conditions.

In the case of jet engines, the fuel is transferred by pumps operating under pressure and the fuel injection is also under pressure in the combustion chamber. Consequently, the engine fuel system does not need any modification. In a few aircraft, the fuel tanks themselves are pressurized (like C-5) but this is for safety and wouldn't affect operations.

The engine oil and lubrication system is also usually pressurized and can operate briefly under reduced gravity conditions.
Work done by NASA indicates that aircraft can be used in zero gravity conditions without any major modifications to systems.

The zero 'g' aircraft don't operate in weightless environment for more than 20-30 seconds and the engine systems should be able to cope during that time. The main concern appears to be the training levels of the pilot.