The National Transportation Safety Board (NTSB) is providing the following information to urge Bombardier, Inc., to take action on the safety recommendations in this letter. These recommendations are intended to prevent the recurrence of windshield arcing, smoke, fire, and overheating on Bombardier DHC-8 airplanes. They are derived from the NTSB's investigation of a June 5, 2015, incident involving United Express flight 4776 (operated by CommutAir) as it approached Bradley International Airport, Windsor Locks, Connecticut. As a result of this investigation, the NTSB is issuing five safety recommendations to Bombardier, Inc.