Editor's note: This article has been updated to include the identity of the second person killed in the accident, which Sonex confirmed June 3.

Editor's note: This article has been updated to include the identity of the second person killed in the accident, which Sonex confirmed June 3.

Sonex Aircraft CEO Jeremy Monnett and assembly mechanic Mike Clark were killed June 2 in an aircraft accident near the company’s headquarters in Oshkosh, Wisconsin.

The two-seat, piston-engine Sonex SA crashed on approach to Wittman Regional Airport.

Monnett, son of Sonex Aircraft LLC Founder and President John Monnett Jr., was known as a friendly, energetic leader, who focused on creating innovative, affordable sport aircraft. Tributes began to pour in through social media in the hours after the accident.

“A great dad, engineer, community leader, and friend,” EAA President Jack Pelton wrote. “Words cannot express how heartbreaking this is for me.”