On August 25, 2015, about 1335 eastern daylight time, an Engineering and Research Ercoupe 415-C, N87172, sustained substantial damage during a precautionary landing at the Newnan Coweta County Airport (CCO), Atlanta, Georgia. The airline transport rated pilot and the private pilot were not injured. The airplane was registered to and operated by the private pilot as a 14 Code of Federal Regulations Part 91 test flight. Visual flight rules conditions were reported at the time of the accident and no flight plan was filed for the local flight that departed from CCO about 1330.

This was the airplane's first test-flight after having an annual inspection and its wings re-installed. The owner, who was a private pilot, said he performed the takeoff, but once it became airborne it banked hard left and the other pilot had to take control. The other pilot stated that he had to apply full right rudder and aileron to maintain level flight. He climbed to 400 ft with full power and turned back to land on the departure runway. Once the airplane was over the runway, the power was reduced and the airplane veered to the left. The pilot corrected for the yaw and the airplane yawed to the right and landed hard next to the runway. The nose gear collapsed and the airplane skidded to a stop damaging the propeller and an engine mount.

A Federal Aviation Administration (FAA) inspector performed a postaccident examination of the airplane and found no mechanical deficiencies that would have precluded normal operation of the airplane's flight controls. The owner also reported that there were no mechanical problems and was unsure why the airplane was so hard to control. He suggested the wing attachments may have partially given-way but there was no way to prove this occurred.

The 88-year old owner held a private pilot certificate for airplane single-engine land. He reported a total of 457 flight hours, of which, 270 hours were in the same make/model as the accident airplane. The owner's last FAA third-class medical was issued on December 3, 2012.

The 52-year old pilot held an airline transport pilot rating for airplane multi-engine land, a commercial certificate for airplane single-engine land and instrument airplane, and a certified flight instructor rating for airplane single and multi-engine land. He was also a certified flight engineer with type ratings for BA-300 and DC-9 airplanes. The pilot reported a total of 7,500 flight hours, of which 50 were in the same make and model airplane as the accident airplane. His last FAA first-class medical was issued on March 10, 2015.

Weather at the airport at 1355 was reported as wind 330 degrees at 4 knots, visibility 10 miles, and clear skies.