We tried something like that a few times in a 3rd ed game. IRL it wouldn't happen, because something that small doesn't have enough lift produced to handle the load, plus the airframe would fall apart in the trying. The extra weight is usually for whatever can be carried internally or for added speed and maneuverability. Since SR is missing a lot of critical info it's really a GM's call.
Example: CH-47 Chinook's engine and rotors are rated a lot higher than what the airframe can handle. That gives it a higher operating altitude, faster laden/unladen speed, and better maneuverability in general. In a pinch you could go past the weight limits on the airframe, if balanced correctly, but I wouldn't do it for long because the fuselage would start to warp and add vibrations and vibrations mess with flight characteristics (critical vibration and ground resonance are very real problems in rotor craft).