It's A 129 helicopter gunship. What is the yellow line pipeline for? Who knows? Thank you.

Yes, this long belt is the ammunition supply device for the 20mm three-tube M 197 machine gun. The reason for this is actually very simple, because A 129 did not install machine guns at the beginning of its design, but used missiles and rockets as its main weapons. Italy's own A 129 didn't have machine guns at first. As shown in the figure.

Later, the operational improvement plan and the "international version" were introduced, and 20mm machine guns were added. This machine gun is detachable and can be quickly loaded and unloaded in the field. Because the original fuselage has no design space to accommodate the ammunition supply system of the machine gun, it can only be exposed.

As for safety, A 129, as a light armed reconnaissance plane, does not particularly emphasize protection. Not only this external ammunition supply system, but also the fuselage of A 129 has no special armor protection. Compared with heavy armed helicopter AH-64, A 129 mainly relies on flexibility and speed to improve safety, and armor or other bullet-proof is only available in key parts.