What happened
Following a fishing trip in Mexico, a flight consisting of the pilot and six passengers departed from Laredo, Texas, after completing customs procedures. During the flight, the pilot reported that an instrument had malfunctioned. While initially cleared to 11,000 feet, the aircraft drifted off course. The pilot subsequently requested a lower altitude of 7,000 feet; however, air traffic controllers could not grant this immediately due to existing traffic in the area.
The pilot noted that the aircraft was flying through significant cloud cover while at 5,000 feet. Approximately seven minutes after receiving clearance for 7,000 feet, controllers observed the aircraft beginning a descent. Subsequent attempts by controllers to contact the crew were unsuccessful. The aircraft eventually crashed, resulting in seven fatalities.
Findings
Investigation into the wreckage revealed that the outer wing panels and the empennage had separated from the airframe. Radar data showed that the aircraft underwent several vertical oscillations of several hundred feet prior to its final descent. Analysis of the fracture surfaces indicated that the structural failures were the result of overload failure.
While other pilots in the vicinity reported only light turbulence within clouds between 3,000 and 6,500 feet, investigators determined that the aircraft was approximately 65 lbs above its maximum gross weight limit. Additionally, the aircraft was loaded near its aft center of gravity. The investigation concluded that the structural separation of the wing spars and stabilizer surfaces was caused by exceeding the design stress limits of the airframe.