Cessna 172K Skyhawk, N79938, operator does business as Western Oregon Flight Services: Accident occurred June 25, 2017 near Roseburg Regional Airport (KRBG), Douglas County, Oregon

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

Analysis 

The pilot reported that he was in the pattern performing touch-and-go landings. During a left descending turn from downwind to base, about ten large birds came into view below the airplane's nose. He recalled that they appeared quickly and that he was unable to take evasive action. He heard and felt a strike, followed by "an appreciable drag on the left side." He also saw visible damage to the left wing. The pilot landed the airplane without further incident. The airplane sustained substantial damage to the left wing ribs and leading edge.

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

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
An in-flight collision with a bird during the approach. 

Findings

Environmental issues
Animal(s)/bird(s) - Ability to respond/compensate (Cause)

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Portland, Oregon

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

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

Operator Does Business As: Western Oregon Flight Services

http://registry.faa.gov/N79938

NTSB Identification: GAA17CA373
14 CFR Part 91: General Aviation
Accident occurred Sunday, June 25, 2017 in Roseburg, OR
Aircraft: CESSNA 172, registration: N79938
Injuries: 3 Uninjured.

NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.

The pilot reported that he was in the pattern performing touch and go landings. During a left descending turn from downwind to base, about ten large birds came into view below the nose of the airplane. He recalled that they appeared quickly and he was unable to take evasive action. He heard and felt a strike, followed by, "an appreciable drag on the left side." He also saw visible damage to the left wing. The pilot landed the airplane without further incident. The airplane sustained substantial damage to the left wing ribs and leading edge.

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