Photogrammetry Measurements of 787 Passenger Entry Doors

Abstract

PROBLEM STATEMENT: All airplanes must be pressurized when altitudes exceed 12,500 feet (3,800 meters). The typical cruise altitude of commercial airliners is between 29,000 and 40,000 feet (8,800 – 12,200 meters). At this altitude, interior cabins are pressurized for safety and passenger comfort. Pressure testing is performed on every line number as part of U.S. Federal Aviation Administration (FAA) requirements. Pressures that are equal to maximum flight altitudes are tested on the ground to ensure air tight integrity of the fuselage and its associated components. Cumulative leakage cannot be greater than the diameter of a US Quarter with the airplane still holding positive pressure. The primary leakage paths on all airplanes are the passenger entry doors. Often times, multiple pressure tests are required to repair the leaks. All repairs must be completed and hold positive pressure before the airplane is allowed to fly. At the inception of any program, an initial test is performed that exerts maximum pressure on the airframe structure. The test is only applied to a single unit and is known as extreme high blow. For the 787, the static test airplane was chosen for the extreme high blow test (static test is the vehicle used to stress, bend and flex the airframe and finally break the wings). During the extreme high blow test, the airframe will experience much more pressure than during any commercial flight.