Cessna 170B, N2580D: Accident occurred January 21, 2015 at Lake Hood Seaplane Base (Z41), Anchorage, Alaska

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Anchorage, Alaska 

Aviation Accident Final Report - National Transportation Safety Board: https://app.ntsb.gov/pdf

Investigation Docket - National Transportation Safety Board: https://dms.ntsb.gov/pubdms

Aviation Accident Data Summary - National Transportation Safety Board: https://app.ntsb.gov/pdf

http://registry.faa.gov/N2580D

NTSB Identification: ANC15LA008
14 CFR Part 91: General Aviation
Accident occurred Wednesday, January 21, 2015 in Anchorage, AK
Probable Cause Approval Date: 07/13/2015
Aircraft: CESSNA 170B, registration: N2580D
Injuries: 4 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The pilot stated that, during the takeoff roll, after he released the brakes and applied full power, the airplane began to veer left. The pilot applied right rudder and right brake in an effort to correct the veer, but the airplane continued to veer left. The airplane then struck a runway edge light and departed the runway into the snow-covered median between the runway and an adjacent taxiway, which resulted in substantial damage to the right wing. A postaccident examination revealed no evidence of any preaccident mechanical anomalies.

The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
The pilot’s loss of directional control during takeoff, which resulted in a runway excursion.

On January 21, 2015 at 1142 Alaska standard time, a tailwheel-equipped, Cessna 170B airplane, N2580D, sustained substantial damage following a loss of control during takeoff from Lake Hood Seaplane Base (Z41), Anchorage, Alaska. The private pilot and three passengers were not injured. The airplane was registered to a private individual and operated by the pilot under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Visual meteorological conditions prevailed and a visual flight rules (VFR) flight plan had been filed.

During an interview with an investigator from the National Transportation Safety Board (NTSB) on January 21, 2015, the pilot stated that during the takeoff roll, after the brakes were released and full power was applied, the airplane began to veer to the left. The pilot applied right rudder and right brake in an effort to correct for the veer, but the airplane continued to the left, struck a runway edge light, and departed the runway into the snow covered median between the runway and an adjacent taxiway, sustaining substantial damage to the right wing. 

A post accident examination of the airplane by the NTSB, along with a Federal Aviation Administration (FAA) aviation safety inspector from the Anchorage Flight Standards District Office revealed no mechanical irregularities that would have precluded normal operation.

A post-accident weight and balance was accomplished by the NTSB using fuel load, passenger weights and seating location provided by the pilot. The aircraft was found to be about 82 pounds over the approved maximum gross weight of 2,200 pounds. The estimated center of gravity at the time of the accident was positive 43.53 inches. The center of gravity range at 2,200 pounds (maximum gross weight) is positive 40.8 inches to positive 46.4 inches.

The closest weather reporting facility is Anchorage International Airport, Anchorage Alaska, less than one mile from the accident site. At 1153, an aviation routine weather report (METAR) from the Anchorage Airport was reporting in part: wind from 120 degrees at 8 knots; sky condition, clear; visibility, 10 statute miles; temperature 12 degrees F; dew point 9 degrees F; altimeter 29.34inHG.