A mobile VOR beacon placed in the Lebombo Mountains near Mbuzini is intended to divert a Tu-134 approaching from the northwest on descent from cruising altitude. The real Maputo VOR is located approximately 80 kilometres to the east-southeast. VOR signals travel line-of-sight only — they cannot bend around terrain. The Lebombo ridge peaks at roughly 600 metres. The aircraft was descending through approximately 1500–2000 metres when it made the fatal turn. Identify the specific geometric relationship between terrain, aircraft altitude, and beacon placement that made the deception operationally viable — and explain why it would fail at higher altitudes.