and proper ways to work in an airport environment. Training is often provided by the particular company or airline, and in the United States usually involves mandatory training by the Federal Aviation Administration and the specific airport management. Hearing tests are usually required upon employment, since working near aircraft engines can strain the eardrums, and have long-term effects. Some ramp agents eventually have back problems from working in enclosed spaces inside an aircraft's cargo compartment, or loading cargo incorrectly. For narrow body aircraft (e.g. Boeing 737, 757), every checked bag is required to be manually transferred to the airplane cargo compartments by carrier baggage handlers. Bags weigh an average of each, but many checked bags exceed the airline allowable weight of . Manual lifting and handling of these bags is considered the main risk factor for work-related musculoskeletal disorders (WMSDs) among baggage handlers. Other factors may increase the risk of WMSDs, including time pressure, and awkward and restricted postures in small cargo compartments. ~In the United States, the National Institute for Occupational Safety and Health (NIOSH) studied the effectiveness of lifting assist devices and other control methods to reduce the risk of WMSDs Examples of accidents Ramp agent killed at Dulles International Airport after colliding with a mobile lounge used to transport passengers Ramp agent killed after losing control of tug at LAX United Airlines Ramp agent falls off a loader and dies Baggage handler at Pearson Airport dies when luggage cart rolls over See also Baggage cart Ground support equipment Line technician (aviation) Loadmaster References External links Hse.gov.uk Aircraft ground handling Air freight Luggage Transport occupations