There was a hijacking in Peru 21 Feb 31 (Pan Am mail Fokker F7 commandeered by revolutionaries to drop leaflets) and a confirmed destruction of a United Boeing 247 on 10 Oct 33 (all 7 killed by nitroglycerine bomb; no prosection). There was also a Phillipine Air Line DC3 destroyed with the loss of all 13 on board on 7 May 49 by "contract" bombers any several hijackings, one with fatal consequences, before the well known Canadian DC3.
Further to Bus429's it was likely to have had a political motive, the passengers being Chinese delegates and jounalists travelling from Hong Kong to Bandung, Indonesia for a conference. An aircraft cleaner was implacated in planting the device.