Innovative Solutions Facilitate Upper-Level Component Maintenance

Oct 10, 2011

The following article was printed in Aviation Maintenance magazine, Oct/Nov issue (http://www.avmain-mag.com/)

     Powerplants, hydraulic systems, rotors, flaps, and countless other components on fixed and rotor wing aircraft require extensive inspection and maintenance, but are out of reach from ground level.  While aircraft designers often incorporate small steps into the body of the aircraft itself for ascending to upper areas, these are far from ideal when it comes to safely and efficiently servicing the aircraft.  If the maintainer is required to carry parts or tooling to these areas, toe-holds are of little use.  The likelihood of dropping or damaging a part or tool during ascension, knocking them off when balancing on top of the aircraft, or worse yet, falling from these upper levels, is great. Any of these possibilities equate to lost time, additional expense, and personal injury.
     OSHA, a division of the US Department of Labor, is responsible for defining minimum requirements that must be met in industry to reduce or prevent injuries on the job.  According to their web site,  "Occupational fatalities caused by falls remain a serious public health problem. The US Department of Labor (DOL) lists falls as one of the leading causes of traumatic occupational death, accounting for eight percent of all occupational fatalities from trauma."
     While facility managers' first concern is for the safety of their workers, there can also be significant financial costs associated with fines levied by safety regulators when operations fail to provide safe and adequate work zones.  In March of this year, OSHA released a list of the "most punished offences."  Not surprisingly, fall protection dominated the top 5:

1.    Faulty scaffolding
2.    Inadequate fall protection
3.    Failure to communicate hazards
4.    Misuse of or faulty ladders
5.    Inadequate respiratory protection

     Additionally, the report goes on to list "inadequate fall protection" as the offense resulting in the heaviest fines.  Penalties exceeding $100,000 are not uncommon, particularly when serious injuries result.  Unfortunately, statistics indicate that many facilities put off addressing the problem until an incident occurs. 

Aviation maintenance

     When working on aircraft, maintainers typically employ one of three primary systems to minimize risks of falling.  The first is the use of personal fall arrest systems. These systems, which typically consist of a full-body harness, an anchor system, and a connecting lanyard or lifeline, safely stop a person who is already falling. These systems require custom fitted equipment, extensive training, and frequent maintenance, but they allow for a certain degree of flexibility, require no floor space, and usually have lower initial costs.
     A second option, fall restraint systems, offer increased safety over fall arrest systems by preventing people from ever reaching a fall hazard. These systems utilize a harness and a lanyard tied off at a set length from an anchor. Though considered somewhat safer than fall arrest systems, fall restraint systems allow less flexibility and still require extensive training, customization, and maintenance.  Both of these tether-type systems require anchor points, either on the aircraft itself or on overhead structures, and considerably limit the mobility of the worker to the radius of the safety line.  Overhead obstacles, such as rotor blades, significantly reduce the practicality of these systems, as workers are not allowed to disconnect the tether from their harness to pass under the obstacles. 
     A third option is the use of mobile work platforms which utilize guardrail systems that prevent a person from reaching a fall hazard. These work stands and decks are considered the safest option for upper-level access, and they require little-to-no training and less frequent maintenance. They can be less flexible than the other options in certain instances, however, and they often have higher up-front costs. Storage of the work stands when not in use can be a drawback, as can their inability to work with every size and type of application the maintainer may encounter.  Advantages, however, include the ability to carry parts, tools, and manuals to the upper regions, as most systems employ stairs to ascend the platform; something impossible with a ladder.  This also allows workers to move efficiently to and from the work zone without having to disconnect from a safety device.  Additionally, work decks provide unrestricted areas to move about, and provide protection against falling to the ground when walking on the aircraft itself, creating a perimeter "safe zone."

Evolution brings improvements

     When specialized aviation maintenance stands were first introduced several years ago, many left a lot to be desired. They had limited flexibility and adjustability; many were manufactured from heavy steel that rusted away in time, while the lighter aluminum versions were under-engineered to provide the strength and durability to traverse hangar door tracks or rough surfaces without breaking.  Many failed to meet the minimum requirements set forth by OSHA, and most were time consuming to assemble and often failed to provide access to critical areas, while often creating obstacles to accessing service points at floor level. Fortunately, the designs and construction of aviation work stands have evolved, resulting in platforms that are far more efficient, effective, and easy to work with, while assuring compliance with military and civilian safety regulations.  Today's user-friendly aviation stands are engineered to not only provide a safe work zone but to also facilitate efficiency, reducing overall process times and accidental component damage.

Phase systems vs point-access stands

     Maintenance stands generally fall into two categories: aircraft-specific phase maintenance systems, which are designed to interface flawlessly with one specific type of aircraft, and multipurpose "point-access" stands, which are versatile enough to be used on many different sizes and types of aircraft at multiple maintenance zones. Most stands offer height adjustability, with ranges of 12", 24", or more. Typically constructed out of lightweight, corrosion-resistant aluminum, deck and stair modules can be easily moved by one or two workers, and are designed to quickly connect together and position.
     Phase systems, normally used for extensive, long-term maintenance operations, offer multiple modules that fully encompass the aircraft, providing a means of accessing the entire upper level, or even multiple levels, while allowing ground-level access beneath the system.  As these are designed to fit specific aircraft, they are more limited for the general maintenance provider, but invaluable to those providing extensive overhaul or refurbishment.  Many decks are equipped with extending deck sections (sliders) that allow the work surface to conform to the contours of the aircraft and accommodate protrusions, while eliminating openings that could allow workers to fall.
     Multipurpose, or universal maintenance stands, can be extremely versatile.  The same 8'-to-12' long deck may be capable of providing ideal access to a tail rotor, jet engine or wing flap.  Often if used in pairs with "cross-over rails" connecting fore and aft, universal stands can provide complete access and safety compliance for rotor and upper deck operations.  These stands set in place in minutes and can reduce overall maintenance time significantly.  This means more hours in the air and less out of service, and equates to greater profitability for the maintenance provider.

Designs based on maintainer feedback

     Spika Welding and Manufacturing of Lewistown, MT is one company that is gaining recognition for its innovative solutions in the field of aviation maintenance equipment. “We have been working with aviation maintainers and technicians since 2006 to develop solutions based on the needs of the users,” said Tom Spika, president of the company. “Using their feedback, we have introduced features that really promote operational efficiency in the hangar. For example, our pneumatic slider-locking system allows maintainers to position sliders and lock them into place simultaneously with the flip of a switch, which is a big time-saver over the old designs.  We've developed a method of snapping the modules together that eliminates having to line up pins and holes, which trims time and simplifies assembly as well.” Spika believes by working closely with those who use the equipment daily, the company is able to respond with better, more effective designs and features, such as the type of material used for the work surface.  "Mechanics were telling us that the up-punched sheet metal used for many older stands ripped their pants when they knelt or sat on it, not to mention the fact it was like a cheese grater to run your hand over.  We found that we could provide an extruded aluminum surface that was far easier on clothing and skin, while still maintaining adequate traction for safety.  Not only that, it doesn't flex and spring like the single layer sheet metal."
     Spika notes that they are focused on designing their platforms to make the maintainer's job easier, while assuring compliance with current OSHA requirements.   Monte Obert, one of the design engineers at Spika, notes that there are many factors that must be considered when engineering a work stand.  "We have to design to meet numerous OSHA regulations that define the requirements for scaffolding, work stands, working surfaces, and stairs, to name a few.  When a customer buys a Spika product, they need to have the assurance that they are meeting all regulations that the government and safety programs dictate."
     According to Obert, those include:

• Engineering the work stand to support 4x the rated working load, with a minimum working load rating of 25 lbs per square foot of deck (OSHA 1921.a)
• Maintaining a minimum ratio of 4:1 for height of deck to width of base(OSHA 1921.a.3)
• Providing 4" toe boards to prevent tools and parts being accidently knocked off (OSHA 1910-29.a.3)
• Maintaining all stair angles between 40° and 60° (OSHA 1926.451)
• Utilizing casters rated at least 4x the working load (OSHA 1910-29.a.4).

    

     Spika agrees that it is imperative that the manufacturer of the work platforms be knowledgeable on the design requirements.  "We see a number of platforms in use in the aviation industry that would never pass an OSHA inspection.  Not only that, they can give a false sense of security to the workers.  No one can afford the cost of a preventable injury.  Our goal is to help facilities prevent that in a way they can see is easily cost-justifiable to management."