What happened
On May 28, 2015, a Cessna 402B, registration OB-1991, operated by Aero Negocios JLE S.A., was performing a scheduled flight from Puerto Esperanza to Pucallpa, Peru. The aircraft was carrying a pilot and four passengers.
During the descent phase, the pilot observed flickering in the VHF radio lights, which was followed by a total loss of communication with the air traffic control tower. Upon investigating, the pilot determined that the aircraft had lost all electrical power. Following the aircraft's checklist, the pilot attempted to test both generators and the battery, but all tests yielded negative results.
As the pilot attempted to configure the aircraft for landing, the flaps and landing gear failed to operate normally. Consequently, the pilot initiated the emergency gear extension procedure. However, the pilot failed to move the gear lever to the down position after the extension process was completed.
While approaching runway 020°, the pilot contacted the tower via cellular phone to declare an emergency and received landing instructions. During the landing, the landing gear partially retracted upon contact with the runway, causing significant damage to the aircraft's fuselage and both engine propellers. The aircraft came to a stop near taxiway Bravo, and airport fire services responded to the scene. There were no injuries to the pilot or the four passengers.
The investigation
The CIAA investigation focused on the electrical failure and the subsequent landing gear malfunction. Field investigations confirmed that the aircraft's battery was actually functioning with a correct charge, though the generators could not be tested. Investigators also determined that the pilot had not completed all required steps of the emergency landing gear extension procedure.