Unfortunately you are using the map (which is pretty small scale for this sort of thing - looks like 1:100,000) as evidence for the detailed local terrain
You'll find that even the Ordnance Survey get it wrong in areas of steep terrain - it's very difficult to render accurately - if you ever read Wainwrights Lakeland Guides he points this out all the time - especially on places such as Scafell Pike or Great Gable
You'd probably have to map at 1:10000 or even 1:5000 to accurately show the terrain on Salak - note the map shows no "sharp ridges" whereas all the photographs of the mountain ( not just at the crash site) show steep ridges all over the place- essentially they are below the resolution of the mapping
which is another reason to stay clear of rapidly rising terrain
