Permanent overhead engineered systems are convenient for both stationary and mobile work such as damage repair, inspections, and routine maintenance along the fuselage. Most systems allow the worker to bypass the brackets hands-free, so the user never has to disconnect from the lifeline, increasing safety and productivity. Depending on the system, one to five workers can be connected to it simultaneously. The disadvantage to these systems is that they cannot be moved.
A mobile system is necessary
Location of the airplane is a primary consideration when selecting a fall protection system. With most aircraft schedules, it is difficult to know the exact tarmac location or hangar an aircraft will be in when maintenance is needed. If the aircraft cannot be parked directly under a permanent system in a hangar, or work needs to be completed on the tarmac, a portable system is required. Leased facilities may lack a permanent overhead system, or the system may be in use. If the task can’t wait, a mobile fall protection system is needed.
There are three main types of mobile fall protection systems: free-standing, aerial lifts, and vacuum anchors. Free-standing systems provide an overhead anchorage point that limits the free-fall distance. Most systems can be maneuvered into place by hand, forklift, or maintenance vehicle. Additional advantages include allowing multiple workers to be tied off to the system and most systems are height-adjustable to work on small or large aircraft. The disadvantage of a free-standing system is that mobility is limited to a safe working range, which varies based on the system.
There are two types of free-standing systems commonly used in the aviation industry: ladder access systems and horizontal rail systems. A ladder access system provides easy access to an elevated work area with fall protection from the ground up, so at no point would a worker be unprotected from a fall. A semi-enclosed platform at the top of the ladder allows a worker to access the wing or fuselage, or perform a quick task on the edge or side of the aircraft. Fall arrest anchorages are located at the top of the platform for attachment of a personal fall arrest system. These systems are ideal for reaching extreme heights such as the tail of a large commercial jet.
Free-standing horizontal rail systems are essentially the same as horizontal rail systems used in overhead permanent engineered systems, except they are mobile and height adjustable. Workers can connect to anchors located on the same or separate rails. A rail system avoids direct contact with the aircraft, but there are height limitations compared to the ladder access system.
Aerial lifts are a good choice for gaining access to an overhead fall protection system or for stationary work. Cherry pickers and scissor lifts are the most commonly used aerial lifts. They provide quick accessibility to the side or edge of the aircraft. A disadvantage of lifts is that they can damage the aircraft if they come into contact with the fuselage or wing. Another disadvantage is the limited positioning in the bucket or cage of a lift device that can quickly cause workers to become uncomfortable and restrict work angles.
Vacuum anchors are the newest fall protection system available for the aviation industry. These systems attach directly to the wing or crown of an aircraft without penetrating or damaging the surface. When vacuum anchors were introduced they were quite heavy and a large air pump was needed to attach the anchor to the aircraft. Today vacuum anchors are lightweight, making them extremely portable, and they offer the option of using an onboard compressed air bottle or connection to an independent air supply to seal the anchor to the surface.
A fall arrest or restraint lanyard, depending on what the anchor is rated for, can be attached to the vacuum anchor and connected to the worker’s full-body harness. For increased mobility, two anchors can be set up with a horizontal lifeline running between them. This configuration allows one or two workers to tie off to the system. The major advantages of the vacuum anchor are its portability and quick setup time. With some systems weighing in at less than 20 pounds, it is extremely easy to transport and set up. The disadvantage is that the system should only be used on larger aircraft due to the fall clearance required when workers are tying off at foot level.