US aircraft manufacturer Boeing is warning about loose bolts in the rudder control system of the 737 MAX model. The US Federal Aviation Administration (FAA) urged operators of newer single-aisle aircraft to inspect certain track rods used to check rudder movements for the loss of parts on Thursday, after an international airline had previously noticed a missing nut on a bolt during routine maintenance. Investors responded with disappointment to the news and the Boeing share price fell by just under 1% as the Dow closed.