Flight Details
The pilot was dispatched on a routine cloud-seeding mission at 2250. All operations through takeoff were normal. After passing through 50 feet above ground level (agl), the airplane would not climb. The pilot verified power on both engines and an airspeed of 120 mph. Raising the landing gear improved climb performance slightly.
Encounter with Microburst
The pilot reported that the maximum altitude achieved was just below 3,100 feet mean sea level (msl), equivalent to 100 feet agl. Rapidly increasing downdrafts from an invisible microburst overpowered any climb performance. The vertical speed indicator (VSI) transitioned from slightly positive to 150+ feet per minute (fpm) negative, pushing the aircraft downward.
Forced Landing
With engines at maximum power, the airplane struck a tree approximately 1 mile from the departure end of the runway. The pilot pitched the nose up in preparation for ground impact. The airplane broke free of the tree. The pilot leveled the wings, lowered the nose slightly to maintain speed, and reduced the throttles to idle. The airplane touched down about 3 to 5 seconds after the collision with the tree. One minute after the crash, heavy rain from a thunderstorm occurred.
Weather Conditions
At 2253, the weather reported at Hettinger, North Dakota (HEI), 34 miles east of BPP, was: few clouds at 8,000 feet agl; broken ceiling at 12,000 feet agl; 10 miles visibility with light rain; winds 100 degrees at 9 knots; temperature 74°F; dew point 68°F; altimeter 29.80 inHg; remarks included lightning in the distance west and northwest, and rain began at 2245. At 2301, conditions were: scattered clouds at 9,000 feet agl; broken ceiling at 12,000 feet agl; 10 miles visibility with light thunderstorms and rain; winds 330 variable 030 at 8 knots; remarks included lightning in the distance west to north; thunderstorms began at 2255. At 2322, conditions were: 3,500 scattered; 10,000 broken; 12,000 overcast; 10 miles visibility with light thunderstorms and rain; winds 030 degrees at 32 knots, gusts to 41 knots; remarks included peak wind 030 degrees at 41 knots recorded at 2317, wind shift at 2302, and lightning in the distance all quadrants.
Examination
An examination of the airplane revealed no anomalies.