An aircraft inflatable harness assembly for an aircraft oxygen crew mask for providing regulated flow of oxygen on board an aircraft for an aircraft crew, comprising: at least one inflatable tube having a normally deflated configuration and an inflated configuration, said at least one inflatable tube having a first end and a second end, said at least one inflatable tube being configured to be inflated to cause expansion of the harness assembly to allow the harness assembly to be placed over a user's head, and said at least one inflatable tube including an outer layer of fabric material coated with an air impermeable surface coating on at least one surface of said outer layer of fabric material to allow said at least one inflatable tube to be inflated; and an inner core of resilient, elastic material disposed within each said at least one inflatable tube, said inner core of resilient, elastic material being fixedly connected between the first and second ends (44;46) of said at least one inflatable tube, said inner core of resilient, elastic material being configured to bias said at least one inflatable tube to a first length when said at least one inflatable tube is in the normally deflated configuration, wherein inflation of said at least one inflatable tube causes said at least one inflatable tube to expand said outer layer of fabric material radially outwardly and axially to a second length greater than the first length, to cause expansion of the harness assembly to allow the harness assembly to be placed over the user's head, and wherein deflation of said at least one inflatable tube causes the aircraft inflatable harness assembly to grip the user's head with a desired head tension, wherein the at least one inflatable tube is pleated in the normally deflated configuration and smooth in the inflated configuration. at least one inflatable tube having a normally deflated configuration and an inflated configuration, said at least one inflatable tube having a first end and a second end, said at least one inflatable tube being configured to be inflated to cause expansion of the harness assembly to allow the harness assembly to be placed over a user's head, and said at least one inflatable tube including an outer layer of fabric material coated with an air impermeable surface coating on at least one surface of said outer layer of fabric material to allow said at least one inflatable tube to be inflated; and an inner core of resilient, elastic material disposed within each said at least one inflatable tube, said inner core of resilient, elastic material being fixedly connected between the first and second ends (44;46) of said at least one inflatable tube, said inner core of resilient, elastic material being configured to bias said at least one inflatable tube to a first length when said at least one inflatable tube is in the normally deflated configuration, wherein inflation of said at least one inflatable tube causes said at least one inflatable tube to expand said outer layer of fabric material radially outwardly and axially to a second length greater than the first length, to cause expansion of the harness assembly to allow the harness assembly to be placed over the user's head, and wherein deflation of said at least one inflatable tube causes the aircraft inflatable harness assembly to grip the user's head with a desired head tension, wherein the at least one inflatable tube is pleated in the normally deflated configuration and smooth in the inflated configuration.