DFW08LA121 · Tromsness Enterprises Inc TURBINE LE

Shortly after departure, the single-engine, turbo propeller equipped airplane was observed in a spiraling descent before it impacted the center median of a major interstate and exploded. An on-scene examination of the airplane revealed that the only identifiable parts of the airplane that remained were the propeller, the engine, a flap, a section of the vertical stabilizer, the elevator, the landing gear and both wing spars. The three-bladed propeller remained attached to the engine; however, one blade had separated from the hub. Examination of the blades revealed that they were curled aft, exhibited leading edge damage and deep gouging from impact with the concrete barrier. The pilot had a history of anxiety, depression, muscle pain, severe headaches, obstructive sleep apnea (OSA), and memory loss, and had recently and regularly been using multiple prescription medications, including three medications for pain, two antidepressants, and a sleep aid, each of which had the potential to adversely affect performance. The pilot was likely suffering from medication-overuse headache, in which overly frequent use of pain medications to control intermittent migraine or tension headaches over time results in a continuous or very frequently recurring headache; his medication combination may have substantially increased his risk for seizure activity; and his OSA may have raised the likelihood of accident involvement. The pilot had not admitted to most of the medications he was using or the medical conditions with which he had been diagnosed on his applications for airman medical certificate, though on one application the pilot had indicated occasional use of a prescription pain medication, and no additional detail was pursued by the FAA.

Verbatim NTSB analysis and probable cause from the NTSB dataset