(Bloomberg) – Consumer advocate Ralph Nader said the larger engines mounted to the Boeing 737 Max spoke to a structure defect and required the plane to be permanently grounded.

The 737 Max “should never fly again,” Nader said. “It is anything but a matter of software. It’s a matter of auxiliary structure deformity: the plane’s motors are a lot for the conventional fuselage.”

Speaking at a flying security occasion in Washington, Nader bludgeoned Boeing Co. for planning the 737 Max up ’til now another modification to an airframe that was first worked in the 1960’s, as opposed to structuring another plane starting with no outside help.

Those larger engines – mounted higher on the 737’s wing than the past rendition of the fly – changed how the plane flies in specific conditions. That drove Boeing to introduce the robotized flight framework that broke down in two lethal crashes by the 737 Max since October, murdering 346 individuals, including Nader’s grandniece. Nader additionally said Boeing’s top chiefs ought to leave, including, “Great sky, they would’ve surrendered in 24 hours in Japan out of disgrace.” The organization is working with controllers on a product fix that will change the flight control framework to keep breakdowns, for example, the one connected to the two accidents from sending planes into wild jumps.

“We stretch out our most profound sympathies to Mr. Nader and to every one of the families and friends and family of those lost in the mishaps on Ethiopian Flight 302 and Lion Air Flight 610,” Boeing representative Charles Bickers said in an email. “Security is our top need as we roll out the improvements important to restore the MAX to support.”