How complex should maintenance procedures be?

As appeared in the RxToday

Maintenance planners and reliability engineers often pose the question: “How much complexity and detail should I include in my job plans and maintenance procedures?” Another question that comes up often is: “What is the best format to use for procedures?”

The level of complexity depends on several factors:

  • The complexity of the task. Tasks which have multiple steps that must be performed in specific sequence, or contain unusual operations, must be spelled out precisely.
  • What specific data is needed to complete the task with repeatable results?  Critical numerical data, such as torque values and clearances, specific type of lubricant, or special tools, should always be spelled out and never left to memory. This information is subject to change, as is your craft person’s memory.
  • The criticality of the procedure’s outcome. How important is it that the job is done exactly right? As the tolerance for poor outcome or any variation in the outcome decreases, the need for specific detail required to ensure a consistent outcome increases sharply. Check-off and inspection steps may be necessary. If your employees’ lives depend on the procedure, write it as if your life depended upon it! But always strive for simplicity and clarity; using simple but precise words and short, unambiguous sentences. You are writing for your people’s understanding, not to win the Pulitzer Prize.

Keep in mind, you do not offend your people’s professional pride when you write procedures that will reinforce their memory and convey critical information. Always write your procedures so that a craftsperson competent with the tools and basic skills of their trade, but who has not done this procedure on this asset before, can use the information provided and perform the task to consistently achieve the desired outcome.  Never assume that because the users of the procedure are skilled and experienced craftspeople they know all of the critical job-specific details. And don’t assume that they will always remember the details accurately. With well-written procedures, the experience of the person executing the procedure may affect how quickly they can complete it, but the experience level of a basically qualified and competent person should never affect the quality of the results.

On the other hand, do not offend them by writing procedures that tell them in painful detail how to use the basic tools of their trade. Telling them to use a #2 Phillips to tighten the screws is not overkill, especially if the screws are located at the top of a long ladder climb and all the other units have slotted head screws.  And if they were left-handed screws, including that in the procedure would be useful information. But if they are standard screws and  you feel it is necessary to have to explain to them how to use that screwdriver, or multi-meter, or other simple tools to get the job done right, then you need to correct that problem at the basic skills training level, not in the procedure.  You are writing procedures, not skills training materials.
One of the best ways to write good procedures and simultaneously engage and utilize your experienced people is to include them in the writing process. Have them spell out how they do it. What tips and tricks have they developed for getting it done? Let them take pride and pass on what they know for the next generation. Have them “test drive” them in the field and give you feedback on how well the procedures actually work and if any errors exist.  

I know that very few of you are interested in aircraft maintenance, but many of you own assets that can have similar cost or safety implications if maintenance is not performed properly. So please bear with me, the lessons do apply. Here are some examples illustrating a few key points:

  • Aircraft engine oil dipsticks are marked in quarts, but do not normally have a minimum or "add oil" mark. It does not take a lot of detail to tell a competent craftsman how to check that level for most engine types. But your procedure needs to contain the acceptable level range and type of oil to use. Maybe your experienced tech has all of this memorized and a simple “Check oil level, replenish as necessary“ is instruction enough. Or is it? The same engine used in different airframe applications has totally different oil operating levels. What if your experienced technician for that airframe type is out sick and a tech from another area, who normally works on other airframe types using the same engine, has to backfill? Or what about a new person in training? Considered in this light, do you still think it is redundant or demeaning to provide details for procedures used by experienced people?
  • What if you change to a new oil type that is incompatible with the old type or incompatible with certain new materials used in that specific application? Including specific materials required for the task is a critical part of any procedure. So is keeping the materials up to date. A simple little failed o-ring can bring an airplane or your process crashing down. And people's memories do fail from time to time. Management of change as part of your Process Safety Management (PSM) is very hard to control if all the data is only in your people’s heads. Well-written, complete procedures support effective PSM.
  • All the experienced aircraft techs know how to pull the dipstick, and to get the true reading only after the aircraft has been sitting level. But experience aside, do they know all they need to know about that plane with a new engine? Some newer engines with gear reduction require that you turn the prop backwards three revolutions to purge oil to the sump before checking it. This is something new that no amount of prior experience will compensate for. Protect your plant and your people. Don't lean on experience and tribal knowledge as a substitute for adequate procedures. Sooner or later it will cost you dearly. Remember, the knowledge gained by experience is lost when the person who gained it (often at your expense) leaves, unless you take the effort to capture it.

Regarding the procedure format; each job has varying degrees of complexity. And different tasks and work environments favor different forms of communication, varying from simple laminated checklists to IPads to procedures that look like entire books on the subject. I suggest that you develop a few simple standard formats that can allow you to pick “the right-size tool for the job". Thus you might have a standard for single page checklists with just a few critical numbers and go/no go limits; a several page step-by-step format for those jobs that have specific sequences; and an extended standard format that references or includes the "big book" for complex and infrequent tasks. It is fine to have more than one standard when needed, but stick to them. No matter how simple or complex, always reference the source documents from which a procedure is created so the craftsman can go back to the source if there is a question and so that configuration management is less difficult.

Some operating environments favor paper, others favor laminated field documents , yet others have great success with electronic format PDAs. In one clean room environment where paper was prohibited and complexity was high, we had all procedures in three-ring books, each page laminated, with pictures and verbal descriptions, all on a roll-around cart. For that working environment it was perfect. I don't think it would work too well inside a distillation column or in a steel mill. Go out and observe the work environment, talk to your people and experiment until you find out what works. Use what works for your people. Then develop standards that work for your environment.

Other factors which will drive the procedure format and distribution method decisions are your infrastructure and your work force skills level.  Some legacy CMMS systems have very limited text fields available and no graphics ability. They may or may not be able to link job plans to specific documents in your procedure library. This may limit your choices. Similarly, at a site where the average maintenance technician knew several programming languages, having procedures on-line, to be printed as needed, was no problem. At another site, basic literacy was very low, so the norm was pre-printed procedures with lots of pictures, distributed with the work order. No matter what you choose, choose formats that work well and can and will be used by your work force. Perfect procedures that go unused are perfectly wasted effort. Remember, you are writing to convey information, and win your people’s support not win the Pulitzer prize.

Always solicit feedback regarding the content, accuracy, sequence of tasks, and clarity of every procedure or job plan. No one is perfect and things do change. So you have to have a feedback loop in place and it must be continually encouraged. In one case the most conscientious new operator destroyed $250k of high speed pumps by carefully and exactingly following an incorrect start up procedure on an unusual pump configuration. All the experienced people knew the procedure was in error and had been ignoring it for years, but it had not been changed. Oops!

There are no perfect answers, nor a “one-size-fits-all answer”. Hopefully by following these guidelines, asking the right questions, and engaging the right people you will find a combination that works well for your organization.

© Life Cycle Engineering, Inc.

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