Boeing Co. is not concerned about a potential disruption to Russian titanium supplies because of tensions over Ukraine, but is keeping a close watch on other industry supply chain pinch points, a senior executive said on Monday. Boeing relies heavily on Russia’s VSMPO-AVISMA for the supply of titanium, a lightweight but strong metal that is used widely in planemaking. Russia has massed over 100,000 troops near Ukraine’s border as it presses demands for a new security arrangement in Europe, prompting U.S. and European officials to threaten a barrage of sanctions if it invades. Boeing Commercial Airplanes head Stan Deal said the U.S. manufacturer had diversified its titanium supply chain since 2014, when Russia was sanctioned for its annexation of Crimea from Ukraine, even though titanium was not directly targeted at the time. “We’ve got a very diverse titanium supply now,” he told reporters in a briefing. “I will tell you …