The IAI Westwind jet departed Toluca (TLC) at 15:16 for a flight to Colima (CLQ), carrying a.o. the governor of the western Mexican state of Colima, Gustavo V zquez Montes. Ten minutes later the aircraft had reached the cruising altitude of FL260. At 15:31 the pilot radioed that he had some flight control problems and that they were diverting to Morelia Airport (MLM). A descent from FL160 was initiated on radial 160 of the Morelia VOR. The aircraft then disappeared from radar and was later found to have crashed in a mountainous area. PROBABLE CAUSE: “Sudden descent during cruise flight and loss of control of the aircraft due to flight control problems”. CONTRIBUTING FACTORS: – Possible failure of the horizontal stabilizer actuator – Possible abrupt change in the attitude of the aircraft due to the position of the centre of gravity – Possible improper crew actions to resolve the emergency. – Possible crew neglect of position and indication of flight controls.