Debate over pulling fuses widens regulatory cracks on 737 Max

Boeing’s 737 Max is set to return to the skies in Canada with a local twist in the cockpit, after Ottawa became the last major Western regulator to lift a 20-month safety ban. Small print in Thursday’s Transport Canada announcement sheds light on a regulatory split over the use of a less common tactic to overcome cockpit distractions, deepening international disunity over the lessons from two fatal crashes. Transport Canada joined the US FAA and other regulators in requiring more training and revisions to MCAS anti-stall software implicated in the crashes in Indonesia and Ethiopia, which killed 346 people. But unlike the FAA, Canada will give pilots an option to intervene in an electrical system to silence an alarm thought to have distracted crew as they tried to control the doomed jets. In an unusual move, pilots in Canada will be allowed to pull a circuit-breaker or electric fuse to silence an erroneously activated “stick shaker,” which vibrates the control column and makes a loud noise when the jet risks losing lift. “Normally, pulling circuit breakers is considered an outdated practice and should only be done when directed by a checklist and not as a method of troubleshooting,” said Tim Perry, president of Air Line Pilots Association (ALPA) Canada. Perry said he backs Canada’s procedure: “Upon thorough evaluation, we deemed it safe.” The Canadian push to let pilots pull a circuit-breaker is further proof of regulators’ willingness to check each other’s homework and could increase pressure to be heard from pilots.<br/>