According to the Peruvian accident investigators, the August 2005 accident involving a TANS Boeing 737 near Pucallpa was caused by a loss of situational awareness in a severe hailstorm on approach to Pucallpa. The flight crew failed to abort the unstabilized approach and continued their fast descent despite the GPWS warnings and the severe storm that they were penetrating. It also appeared that a copilot under instruction was in the right hand seat while the regular copilot was in the passenger cabin at the time of the accident. (CIAA)