This was the crux of a Boeing circular to airlines after the Lion Air crash, which was made an Airworthiness Directive by the US Federal Aviation Authority. A 175-seat Boeing 737 Max 8 flying cross country generates many more ASMs than a smaller Boeing 737-700, with 143 seats, flying form Chicago to St. Louis.
In a statement Wednesday, Southwest downplayed the effects of the grounding, noting its 34 Boeing 737 Max aircraft, the most of any USA airline, account for fewer than 5 percent of the airline's fleet.
"We are doing everything we can to understand the cause of the accidents in partnership with the investigators, deploy safety enhancements and help ensure this does not happen again", Boeing president and chief executive Dennis Muilenburg said.
"There must be a rigorous investigation into why the aircraft, which has critical safety systems that did not exist on prior models, was certified without requiring additional pilot training", he said.
"Air Canada's cancellation and rebooking policies are in place with full fee waiver for affected customers", the airline said in a statement posted to its website.
Mah said Air Canada has made arrangements including re-scheduling widebody aircraft to serve Hawaii starting Wednesday.
"The grounding will remain in effect pending further investigation, including examination of information from the aircraft's flight data recorders and cockpit voice recorders", the FAA said in a statement.
Transport Minister Marc Garneau said Canada had received new satellite data on Wednesday morning that resulted in the safety notice.
Many countries worldwide have grounded Max 8 jets after one operated by Ethiopian Airlines crashed on Sunday, killing 157 people.
A stall occurs when an aircraft's angle of attack (AOA)-the relative angle of the aircraft's wing surfaces to the flow of air across them-reaches the point where the wing can no longer generate enough lift to sustain flight. But a brand is at stake as well.
Shares in Boeing ticked higher to $377 each following the announcement.
The planemaker has lost more than $26 billion (€22 billion) in market value since the crash - a rare slump considering investors are not really known to be spooked by such tragedies.
The Oslo-based airline has 18 "MAX" passenger jets in its 163-aircraft fleet. In October previous year 189 people died when Lion Air's flight ET302 crashed off the coast of Indonesia. In certain circumstances, the planes' systems try to tilt their noses down, contrary to the efforts of pilots - a pattern that was seen in both flights before they crashed, he said.
Shortly after, and possibly because, details of that telephone conversation surfaced, and with Canada bringing down the ban hammer, the FAA was allowed to ground 737 Maxes. They are voluntary safety reports and do not publicly reveal the names of pilots, the airlines or the location of the incidents.
In both cases, pilots were forced to intervene to stop the plane from descending.