HISTORY OF FLIGHTOn September 14, 2018, about 1120 Pacific daylight time, an experimental Gruber Beelzabub airplane, N382T, was substantially damaged when it was involved in an accident near Rochester, Washington. The pilot/owner and pilot-rated passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane departed Flying B Airport (8WA0), Rainier, Washington, at an undetermined time, and no flight plan had been filed. A witness reported observing the airplane about 500 ft above ground level just east of their job site. The airplane circled around a single tree, leveled off, and began a descent. The airplane was in a wings-level attitude when the left wing struck a 60–70 ft tall tree. The witness reported that the engine was running. WRECKAGE AND IMPACT INFORMATIONThe accident area was located on a hilltop whose trees were being cleared. The trees in the area where the airplane came to rest, were between 30-50 ft tall and were downslope from the single tree that the airplane impacted. The tree impacted was about 60-70 ft tall and about 500 feet from the main wreckage. The airplane came to rest in a nose-down attitude with the empennage against a tree. The left wing and left horizontal stabilizer separated from the airframe; a portion of the left wing came to rest in a tree about 500 ft from the main wreckage. A landing gear wheel separated and was located on the road adjacent to the forested area. The fuel tank had been breached and the smell of fuel was present along with damaged foliage. The tailwheel remained attached in its normal position. The fabric cover was torn away from the undercarriage and exposed the flight control tubes. The control tubes and cables remained connected via their associated hardware. Flight control continuity was established via flight control cables. The landing gear bungees remained in place and not damaged. The engine separated from the airframe and came to rest adjacent to the nose of the airplane. There were no obvious holes in the crankcase. The propeller assembly remained attached to the engine. The two-bladed Curtiss propeller remained attached to the crankshaft. One propeller blade was bent midspan; the tip was missing. The other blade was relatively straight with bending at the outboard tip portion of the blade. Visual inspection of the engine revealed no obvious holes in the crankcase. The fuel strainer was removed and was free of debris. Mechanical and valve train continuity were established by manual rotation of the engine. MEDICAL AND PATHOLOGICAL INFORMATIONThe Thurston County Coroner performed autopsies of both pilots and determined their cause of death to be blunt force trauma of the head. Toxicology testing performed by the Federal Aviation Administration Forensic Sciences laboratory of the pilot/owner revealed no carbon monoxide, volatiles, or tested-for drugs. The toxicology testing did not perform testing for cyanide. Toxicology testing performed for the pilot-rated passenger detected no volatiles; and carbon monoxide and cyanide testing was not performed. The toxicology detected 0.045 (ug/mL, ug/g) morphine in urine but not in the blood cavity. Morphine is an opiate narcotic indicated for the management of severe and chronic pain; morphine may also be present as a metabolite of the opiate codeine. Use of morphine carries a high risk of addiction, abuse, and misuse. It is an impairing medication and carries the warning that patients should not drive or operate dangerous machinery until they know how they will react to the medication. The half-life of morphine is between 1.3 and 6.7 hours and it has a therapeutic range of 10 to 100 ng/mL. Morphine is metabolized mainly in the liver; normorphine is a major inactive metabolite. About 10% of a morphine dose is excreted unchanged in the urine. The investigation was unable to determine which occupant was flying the airplane at the time of the accident.