Boeing 737 MAX mid-air emergencies revealed as US agency prepares to probe production issues

Boeing 737 MAX under scrutiny after multiple mid-air emergencies. (ABC 7.30: Kathryn Diss and John Stewart)

Boeing's troubled 737 MAX planes — which have twice crashed, killing 346 people — have experienced at least six mid-air emergencies and dozens of groundings in the year after an extensive probe cleared them to fly.