The aircraft undershot runway 29 at Cozumel Airport, Mexico, during a visual approach. It operated on a flight from Kingston, Jamaica, to Houston, Texas, USA with an en route stop at Cozumel. The flight contacted Cozumel Tower at 18:33 hours, reporting at 14 DME. The controller then cleared the flight for a VOR/DME approach to runway 29 and to report passing the VOR or field at sight. One minute later, the crew reported having the field in sight and so requested to make a visual approach, directly to runway 29. The controller authorized this and instructed to report at 5 DME. The aircraft was subsequently cleared to land, with wind reported to be calm. The final approach was low and the aircraft hit the ground 500 m short of the threshold. Probable cause: “Impact with the ground during approach in twilight conditions (evening twilight), with wrong altimetric adjustment (QNH) in the instruments of the copilot, during an operation carried out under visual flight rules (VFR)”.