CEN21LA096

The pilot requested a right turn after takeoff, which was approved by the local control (LC) controller. Shortly after departure, the LC controller instructed the pilot to keep the turn tight to avoid the airspace of a nearby airport. A witness said the airplane’s bank angle increased significantly during the turn before entering a steep dive. After the airplane began the dive, the witness heard the engine power up to what sounded like full power. The airplane impacted a light pole, a road, and then stuck an automobile after which a postaccident fire ensued. The witness said the airplane may have entered an accelerated stall. Postaccident examination of the airplane revealed no mechanical anomalies that would have precluded normal airplane operation. The pilot did not appear to have any natural disease that would be a factor in this accident. While his autopsy described an enlarged heart, the size was within normal limits for his last known pre-accident weight. The pilot had likely taken cold and allergy medication some time before flying. Toxicology testing detected the opioid cough suppressant dihydrocodeine in his urine but not in his blood, so no impairing effects would be expected. The sedating antihistamine diphenhydramine was detected in the pilot’s cavity and heart blood. The pilot-rated passenger also had diphenhydramine detected in his chest cavity blood. Given postmortem redistribution, the amounts detected were likely subtherapeutic. Given the circumstances of this crash, it is unlikely that the effects from the pilot’s and pilot-rated passenger’s use of diphenhydramine contributed to this accident.

On December 21, 2020, about 1452 central standard time, an Express CT, N772BM, was involved in an accident near Grand Prairie, Texas. The private pilot and the pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The Grand Prairie Municipal Airport (GPM), Grand Prairie, Texas, ground controller instructed the pilot to taxi to runway 17. The pilot requested flight following to the Denton Enterprise Airport (DTO), Denton, Texas. The local control (LC) controller cleared the pilot for takeoff on runway 17 and the pilot requested a right turn, which was approved. The LC controller observed the airplane on the tower display workstation and noticed it was headed for Arlington Municipal Airport (GKY), Arlington, Texas, airspace. The LC controller instructed the pilot to keep the turn “tight” to remain outside of GKY’s airspace and to contact departure; however, there was no response. A witness stated he was standing on the ramp and saw the airplane takeoff from runway 17. After takeoff, the airplane entered a right crosswind and began a turn north for a right downwind departure. He said the air traffic control tower instructed the flight to "keep it tight” to avoid GKY airspace. The airplane’s bank angle increased significantly before entering a steep dive. After the airplane began the dive, the witness heard the engine power up to what sounded like full power. Shortly after, he lost sight of the airplane and then saw the plume of smoke from the impact. He said that it appeared him that the airplane may have entered an accelerated stall while trying to avoid the GKY airspace. The airplane impacted a light pole, a road, and then stuck an automobile after which a post-impact fire ensued. According to the autopsy report for the pilot, the cause of death of the pilot was blunt force injuries with thermal trauma due to an airplane crash and the manner of death was accident. Although the examination was limited by trauma, other than an enlarged heart (475 grams), no other significant natural disease was identified. Toxicological testing identified the antihistamine diphenhydramine in the pilot’s cavity blood at 68 nanograms per milliliter (ng/mL), heart blood at 116 ng/mL, and in his urine and his liver tissue. The decongestant pseudoephedrine was detected in the pilot’s cavity blood, heart blood at 264 ng/mL, and urine and the opioid cough suppressant dihydrocodeine was detected in his urine at 12 ng/mL. According to the autopsy report for the pilot-rated passenger, the cause of death was blunt force injuries with thermal trauma due to an airplane crash and the manner of death was accident. No significant natural disease was identified. Toxicology testing detected diphenhydramine at 132 ng/mL in the pilot-rated passenger’s chest cavity blood. Commonly marketed as Benadryl, diphenhydramine is available over the counter in many products used to treat colds, allergies, andinsomnia. Diphenhydramine carries the warning that use of the medication may impair mental and physical ability to perform potentially hazardous tasks, including driving or operating heavy machinery. The therapeutic range is 50 to 100 ng/mL, and it has a half-life of 3 to 14 hours. Diphenhydramine undergoes postmortem distribution and central levels may be two to three times higher than peripheral levels. The FAA provides guidance on wait times before flying after using this medication; post-dose observation time is 60 hours, and the medication is not for daily use. Pseudoephedrine is generally non-impairing and dihydrocodeine can cause drowsiness. Pseudoephedrine and dihydrocodeine are often found in over-the-counter cold and allergy medications often in combination with an antihistamine. The airplane came to rest in an upright position and was destroyed by impact forces and a postcrash fire. A postaccident examination of the airplane confirmed flight control continuity from the control surfaces to the cockpit controls. Engine valve and drive continuity was confirmed. Cylinder compression was confirmed when the propeller was rotated through by hand. A borescope examination of the engine cylinders did not reveal any abnormal features. The fuel injector screen did not contain debris. The propeller governor oil screen did not contain debris. The engine accessories were destroyed by fire and could not be tested.