A Sunwing Airlines Boeing 737 MAX 8, registration C-GMXB performing flight WG-439 from Punta Cana (Dominican Republic) to Toronto, ON (Canada) with 176 passengers and 6 crew, was en route at FL350 about 50nm northwest of Washington Dulles Airport,DC (USA) when the captain’s instruments began to show erroneous indications. The first officer was handed control of the aircraft as his instruments and the standby instruments remained in agreement. The crew decided to descend out of IMC into VMC as a precaution and descended the aircraft to FL250. Descending through FL280 the weather radar and TCAS failed. The crew declared PAN PAN emergency and worked the related checklists. The left IRS fault light illuminated. The flight continued to Toronto for a safe landing without further incident.
The Canadian TSB reported the left ADIRU was replaced.
This aircraft is only 7 months old and comes after the recent Lionair 737 Max crash in Indonesia.