Borescopes are widely used for civil aviation engine inspection. In this paper, a novel scaled shape from shading (SFS) approach is proposed to measure the civil aviation engine chambers with 3D information from the borescope images. In this work, a more accurate point light source model is firstly investigated. By introducing the matrix of camera, the relationship between the CCD grayscale image and the surface depth map is developed, which enables the new method can recover the 3D information of the surface with only one image. Under the constraints of brightness, smoothness and integrability, the depth map of surface is calculated through iteration. To evaluate our method, three synthetic images were simulated. By using the ratio of RMSE as criteria, the simulation results show a perfect match with the errors of 1.19%, 1.01% and 1.16%, respectively. In the experiment, the nozzle inner wall with clear features of Turbomeca Turmo IV C, a helicopter engine of Safran, is measured and its 3D shape is successfully recovered. The results prove the effectiveness of this method and show great potential of applications in civil aviation engine inspection.