Accident
A four-engine cargo aircraft departed Mexico City-Benito Juarez Airport at 1700LT on a flight to Miami-Intl, Florida. The aircraft carried eight passengers, four crew members, and a load of 18 racing horses. After takeoff, during the initial climb, the aircraft encountered difficulties gaining sufficient altitude. The crew added power, but the aircraft failed to gain height. The captain attempted an emergency landing on a road, but the aircraft struck power lines and crashed in the city, a few kilometers from the airport. The aircraft and several houses and buildings were destroyed. The captain was rescued; 11 other occupants and 54 people on the ground were killed, and 50 people were wounded, some seriously.
Investigation
The official investigation determined several factors. The total weight of the aircraft was well above the maximum takeoff weight (MTOW) at the time of the accident. Additionally, the fuel stored in the tanks did not have the correct octane number; it had an index of 100 when it should have presented an index estimated between 130 and 145. This was presumably caused by poor flight preparation on the part of the crew and ground personnel. Due to the insufficient octane index, the engine failed to provide sufficient power during the initial climb, which was considered a contributing factor. It was also reported that the horses panicked and moved in the cabin, causing the center of gravity (CofG) to be modified. In such conditions, the aircraft became unstable and difficult to control.
Probable Cause
The probable cause, as stated in the official findings, includes the total weight of the aircraft being well above the MTOW, improper fuel octane number due to poor flight preparation by crew and ground personnel, and the movement of horses causing a shift in the center of gravity, leading to instability and loss of control.