a) September 25th 2017. Looking further through The Adventures of Tintin: Tintin In Tibet, I looked at the illustration of a crashed plan and suddenly it starts to reveal in my mind that it served as a starting point for another concept illustration for Alien, and then oddly I matched it up with Chris Foss' derelict ship number 3
b) The black angular shadow in a piece of wreckage suddenly shows itself up in my mind as a starting point for the repeating triangular pattern across what might be the ships engines.
c) Perhaps he made use of the dark space with window in the back part of the plane and generally speaking used the effect on the side of the ship as a shadow with a white space
d) The propeller blade becomes the large feature on the fin that's repeated on another in the background. They lean towards the same direction in the composition.
e) Propeller blades in the distance become the arrangement of fins on the top of the derelict. There are also the tale fins of the plane to consider in the illustration and one might consider the result to be a merger between these ideas