This work proposed on the incorporation of fiber Bragg grating (FBG) sensors into aluminium alloy structures for the purpose of monitoring crack growth. Two types of crack are designed and simulated in this structure. By considering the pre crack length in the two metal structure wavelength propagation has been monitored with FBG sensor in the experimental investigation. In the case of edge cracks, the wavelength change observed during crack propagation varied from 0 to 6 nm, with an initial shift of 1 nm to 6 nm occurring within the first 20 mm of crack propagation. Once the crack reached a stable stress state, the wavelength change became consistent. Similar findings were observed for FBG sensors placed at different positions. In the case of inclined crack propagation, the wavelength change ranged from 0 to 5 nm for crack positions ranging from 0 to 120 mm. The integration of sensor technology into aluminium alloy structures has the potential to revolutionize the field of structural engineering, enhancing safety and increasing the lifespan of structures.