TAESA flight 725, a DC-9-30, crashed after takeoff from Uruapan Airport, Mexico, killing all 18 occupants. Flight 725 was a scheduled service from Tijuana to Mexico City with en route stops at Guadalajara and Uruapan. The DC-9-31 was scheduled to depart from Uruapan at 18:25 for the final 45-minute leg to Mexico City. The aircraft took off from runway 20 at 18:59 when 85 passengers had deplaned at Uruapan. Witnesses reported that the airplane assumed a higher than normal nose high attitude as soon as it departed. The airplane impacted the ground in a nose low attitude on a heading of 110 degrees in an avocado grove located on the east side of the departure course, 3.3 DME south of the airport. Prior to entering service with TAESA June 1998, the aircraft had been used by NASA and was modified to support the reduced-gravity mission. As N650UG completed 193 flights for NASA (TT 436.3 hours) between May 29, 1995 and July 11, 1997. Probable cause: “Crash of the aircraft, after an overrotation on takeoff and a climb with a very pronounced angle, which caused the loss of control, with spatial disorientation (loss of the horizon), in a flight operation by instruments (IFR), in which, according to the crew, there was a possible failure of asymmetry indication in the leading edge flaps (slats), with the crew neglecting to control the flight of the aircraft.” Contributing factors 1.- Inadequate preparation of information for instrument take-off (IFR) from Uruapan airport and failure to adhere to the operating procedures of the Aeronautical Information Publication (AIP) Manual. 2.- Failure to perform checklist procedures for the operation of the aircraft in its different phases. 3.- Loss of external vision (spatial disorientation), aggravated by turning on the cockpit lights, before the takeoff run. 4.- Inadequate procedure for the rotation of the aircraft during take-off, dragging the tail skid on the runway 5.- Angle of climb greater than that established in the aircraft Operations Manual. 6.- Lack of cockpit resource management (CRM).