A Learjet 35A impacted the side of El Bachoco Mountain at 1800 feet while on approach to Hermosillo Airport, Mexico. The aircraft departed Mexico City International Airport at 07:15 hours local time. The en route part of the flight was uneventful and the flight was cleared to descend. At 08:34 local time, the flight contacted Hermosillo approach control, reporting that they were leaving 23000 feet for 20000 feet at 47 miles from the airport. The controller reported that weather conditions were poor with a visibility of half to three-quarters of a mile, indefinite ceiling and light rain. The flight was then cleared to 6000 feet for the Miura One arrival for runway 23. The aircraft reached 6000 feet at 08:41 hours and five minutes later they were at 10 DME, intercepting the 320 radial towards the airport. The flight was then advised to report when they had runway the in sight. This was read back accordingly. This was the last radio contact with the flight. Five hours hours later, the aircraft was located. It had crashed 6.5 miles northeast of VOR Hermosillo, on the rocky slope of a hill at 1800 feet. Probable cause: ‘Not maintaining the established altitude (2800 feet), in the approach procedure (arrival Ortiz one) in the Aeronautical Information Manual (AIP), for an instrument landing, in low visibility conditions, colliding with the ground at 1800 feet.’A Learjet 35A impacted the side of El Bachoco Mountain at 1800 feet while on approach to Hermosillo Airport, Mexico. The aircraft departed Mexico City International Airport at 07:15 hours local time. The en route part of the flight was uneventful and the flight was cleared to descend. At 08:34 local time, the flight contacted Hermosillo approach control, reporting that they were leaving 23000 feet for 20000 feet at 47 miles from the airport. The controller reported that weather conditions were poor with a visibility of half to three-quarters of a mile, indefinite ceiling and light rain. The flight was then cleared to 6000 feet for the Miura One arrival for runway 23. The aircraft reached 6000 feet at 08:41 hours and five minutes later they were at 10 DME, intercepting the 320 radial towards the airport. The flight was then advised to report when they had runway the in sight. This was read back accordingly. This was the last radio contact with the flight. Five hours hours later, the aircraft was located. It had crashed 6.5 miles northeast of VOR Hermosillo, on the rocky slope of a hill at 1800 feet. Probable cause: ‘Not maintaining the established altitude (2800 feet), in the approach procedure (arrival Ortiz one) in the Aeronautical Information Manual (AIP), for an instrument landing, in low visibility conditions, colliding with the ground at 1800 feet.’