Aircraft Accident/Incident Report

Bryan, Texas 77803
Monday, December 19, 2011 21:50 CST

The airplane was on a cross-country flight in level cruise flight about 8,000 feet msl when the pilot flew into an area of heavy rain showers. The pilot informed an air traffic controller that he was diverting around an area of thunderstorms. The pilot last reported that he was in “bad” weather and was going to try to get out of it. Following that transmission, radio and radar contact was lost. A witness on the ground heard a sound resembling an explosion. She reported that at the time she heard the noise the rain was falling as a light drizzle. However, by the time she and her husband got outside to see what the explosion was, the rain started “pouring down.” The witness’s husband found the airplane’s main wreckage about 450 feet southwest of their house. The main wreckage consisted of the entire airplane except for the left wing, vertical stabilizer, rudder, and the right wing tip fuel tank. Those components were located about 200 feet north-northeast of the main wreckage. An examination of the left wing spar showed that the wing failed in positive overload. Flight control continuity was confirmed at the accident site. A postcrash examination of the airplane’s engine and other systems did not reveal any preimpact anomalies. A weather study of conditions in the area at the time of the accident indicated the potential for heavy rain showers, thunderstorms, wind in excess of 45 knots, clear air turbulence, and low-level wind shear. While the pilot’s toxicology testing results were positive for tetrahydrocannabinol carboxylic acid (marijuana) in the liver and kidney, the levels were determined not to be impairing. The pilot had a global positioning system (GPS) unit with a current subscription for Next-Generation Radar (NEXRAD). At the time of the accident the depiction in the cockpit would have reflected weather conditions that occurred a couple of minutes earlier. The GPS unit’s owner’s manual states that NEXRAD weather data should be used for “long-range planning purposes only,” and not to “penetrate hazardous weather,” as the “NEXRAD data is not real-time.” On June 19, 2012, the NTSB issued a Safety Alert to warn pilots using in-cockpit flight information services broadcasts (FIS-B) and satellite weather display systems that the NEXRAD "age indicator" can be misleading. The actual NEXRAD data can be as much as 20 minutes older than the age indication on the display in the cockpit. If misinterpreted, this difference in time can present potentially serious safety hazards to aircraft operating in the vicinity of fast-moving and quickly developing weather systems. In addition to raising pilot awareness on this issue, the Safety Alert also reminds pilots of the importance of obtaining a thorough preflight weather briefing.

The pilot’s inadvertent encounter with severe weather, which resulted in the airplane’s left wing failing in positive overload. Contributing to the accident was the pilot’s reliance on outdated weather information that he received on his in-cockpit Next-Generation Radar (NEXRAD).