No fatalities

24 Sep 2015: CESSNA 170B — Arctic Village, AK

Arctic Village, AK, United States

On 24 Sep 2015, a CESSNA 170B UNDESIGNAT was involved in an aviation accident near Arctic Village, AK. No fatalities were reported. Investigators recorded the probable cause as: The pilot exceeded the critical angle of attack during takeoff, which resulted in an aerodynamic stall and a collision with terrain. This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.

SourcesNTSBPrimary reportUpdated 1778583330Data APIEditorial standards

A pilot reported that after takeoff from a frozen gravel bar in remote Alaska, the airplane stalled, struck a cut bank, and sustained substantial damage. No mechanical failures were identified.

Accident Details

The pilot reported that the accident occurred after takeoff from a frozen gravel bar located adjacent to a river in a remote wilderness area. During the takeoff, the airplane stalled. Subsequently, the left main landing gear struck the edge of a cut bank, and the left wing impacted the ground. The fuselage then impacted the top of the bank and spun counterclockwise. As a result, the left wing separated from the fuselage, and the fuselage sustained substantial damage.

Pilot Report

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

Safety Recommendations

In his report, the pilot provided a safety recommendation. He suggested that for future operations, he would take off empty or with minimal known weight to ensure the aircraft would perform as planned. He noted that he could then land to reload or, if partially loaded, fly to a longer gravel bar and stage from there, returning empty to the origin point and continuing to shuttle gear and people. The pilot emphasized that the first flight would have been better planned without another person on board, not solely due to weight but also due to the risk posed to that person.

Additional Information

The Alaskan Aviation Safety Foundation has published a safety briefing titled "Off Airport Landings," which discusses considerations for off-airport takeoff and landing operations. The briefing advises that when flying very low and slow on takeoff or landing approach, pilots should avoid flying over an abrupt drop-off such as a cut bank or steep lake shore, as this can result in an abrupt loss of ground effect and cause the aircraft to settle. The briefing also lists factors to consider when selecting off-airport takeoff and landing sites, including airplane load (noting that every gram counts), density altitude (which can change even without going into the mountains), ground drag (thawed gravel bars present more drag than frozen ones), and departure obstacles (emphasizing the need for additional space to clear obstacles when flying in ground effect).

Contributing factors

PilotAngle of attack — Not attained/maintained