Complex sentence: In applying the sealant the operator was required to access the inside of the fuel tank using small removable inspection hatches in the top surface of the wing, and of necessity, this resulted in poor visibility and awkward conditions for working inside the tank.
Split into simpler sentences: In applying the sealant, the operator was required to access the inside of the fuel tank using small removable inspection hatches in the top surface of the wing. This resulted in poor visibility and awkward conditions for working inside the tank.