N68857Helio H-295 · 1974

The pilot reported that during takeoff, in gusty wind conditions, from a remote unimproved airstrip that was located along a river, the takeoff roll was normal. After the airplane became airborne, he initiated a turn to the right, and the right wing dropped suddenly and impacted a “root wad”. The pilot recovered airplane control after the impact and continued the flight back to the base airport without further incident.

The airplane sustained substantial damage to the right wing and fuselage.

The pilot reported no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

On September 25, 2016, about 1600 Alaska daylight time, a tundra tire-equipped Helio Courier H-295 airplane, N68857, sustained substantial damage following a runway excursion during takeoff from a remote, unimproved airstrip about 35 miles southwest of Delta Junction, Alaska. The certificated airline transport pilot, the sole occupant of the airplane, sustained no injury. The airplane was registered to Bursiel Equipment, Inc., Fairbanks, Alaska, and was being operated by Wright Air Service, Fairbanks, as a visual flight rules (VFR) on-demand commercial flight under the provisions of 14 Code of Federal Regulations (CFR) Part 135. Visual meteorological conditions prevailed at the time of the accident, and a VFR flight plan had been filed. The flight originated from the Fairbanks International Airport, Fairbanks, about 1500.

During a telephone interview with the National Transportation Safety Board (NTSB) investigator-in-charge on September 26, the pilot stated that airplane landed at the 800-foot gravel airstrip near the East Fork of the Little Delta River about 1540 to transport moose meat for a customer to Fairbanks. The moose meat was weighed at 625 pounds before being loaded into the airplane. The pilot reported on the NTSB Form 6120.1 Pilot/Operator Aircraft Accident/Incident Report that about 1-2 inches of wet snow had accumulated on the gravel airstrip and winds originated from the north/northeast estimated at 7 knots. Additionally, marginal visual flight rules conditions were reported by the pilot as 5 statute miles with light snow. He reported he calculated his takeoff weight at 3400 pounds with a "middle center of gravity location."

The pilot stated that after conducting a pre-takeoff contamination check of the airplane, the flaps were set to 30 degrees, the trim set for takeoff, and the before takeoff checklist was completed. He positioned the airplane for a departure to the north, prior to locking the tail wheel, confirming the flaps and trim were set, and selecting a go/no-go point about 400 feet down the airstrip. The pilot began the takeoff sequence and reported that the initial indications were for a normal takeoff through the selected go/no-go decision point. With about one third of the airstrip remaining, the pilot realized the airplane would not become airborne at the designated go/no-go decision point and that he would be unable to stop in the remaining distance if he rejected the takeoff due to the snow on the airstrip. He elected to continue the takeoff through the low brush at the end of the airstrip in an attempt to gain more airspeed. He reported that the airplane became airborne, settled back to the surface, before becoming airborne again. The main landing gear impacted brush on a small embankment and the airplane began to settle. The pilot observed a clear area ahead of the airstrip that lead into a creek bed; he reduced the power to idle, and held full aft pressure on the control yoke. The airplane settled to the surface in a three-point attitude, and came to rest in the creek bed with a left wing low attitude. Upon exiting the airplane in the creek bed, the pilot noted that the wind had become calm and the snow fall had stopped.

The airplane sustained substantial damage to the vertical stabilizer.

The pilot stated there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.

The closest weather reporting facility was the Allen Army Airfield, Fort Greely, Alaska, about 35 miles northeast of the accident site. At 1559, an Aviation Routine Weather Report (METAR) was reporting in part: wind, calm; visibility 10 statute miles; sky condition, scattered clouds 1,300 feet, broken clouds 3,200 feet; temperature 37 degrees F; dew point 36 degrees F; altimeter 29.93 inHg.

Helio H-295 Airplane Flight Manual

The Helio H-295 Airplane Flight Manual includes various performance charts for determining the values for takeoff ground run and takeoff distance to clear a 50-foot obstacle. The performance chart for determining the values for the takeoff ground run has correction factors for wet grass and soft turf, but not for wet snow. The performance chart for determining the values for the takeoff distance to clear a 50-foot obstacle does not incorporate any correction factors for the pilot to utilize.

Soft Field Operations

The Federal Aviation Administration has published FAA-H-8083-3A Airplane Flying Handbook (2004). This document discusses takeoff considerations from soft fields and states in part:

Takeoffs and climbs from soft fields require the use of operational techniques for getting the airplane airborne as quickly as possible to eliminate the drag caused by tall grass, soft sand, mud, and snow, and may or may not require climbing over an obstacle. The technique makes judicious use of ground effect and requires a feel for the airplane and fine control touch. Soft surfaces or long, wet grass usually reduces the airplane's acceleration during the takeoff roll so much that adequate takeoff speed might not be attained if normal takeoff techniques were employed.

Takeoff and Obstacle Clearance Considerations

The Civil Aviation Authority of New Zealand has published Takeoff and Landing Performance (2011). This document discusses takeoff and obstacle clearance considerations and states in part:

Grass, soft ground or snow increase the rolling resistance and therefore the takeoff ground run will be longer than on a sealed or paved runway.

Plan to clear obstacles on the climb out path by at least 50 feet. Consider what your aircraft's climb gradient is likely to be as part of your takeoff performance calculations – especially if terrain, wires, and the possibility of downdraughts are factors in the climb out path.