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MAINTENANCE AND CERTIFICATION

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Your Engine is Approaching TBO-Now What?

by Joe Escobar, Editor, Aircraft Maintenance Technology(AMT) on-line magazine(http://www.amtonline.com/). This article originally appeared in the March 2006 issue of AMT Magazine, and is reprinted with permission.

As an engine gets older, builds operating hours, and approaches TBO [time between overhauls](either based on operating hours or calendar limits) owners start to ask questions concerning the decision to either continue flying, have a top overhaul or major overhaul performed, or exchange engines. The following nine points are offered by Lycoming to help owners and mechanics evaluate each engine and make such a decision.

  1. Oil consumption-any unusual increase?
  2. Engine history and calendar age.
  3. Pilot's opinion of the engine.
  4. How has the engine been operated?
  5. Maintenance-what kind has the engine received?
  6. What does the oil filter tell?
  7. What has been the trend in compression checks?
  8. What do the spark plugs show?
  9. Refer to the engine manufacturer's service letter for engine life and recommended overhaul periods.

Lycoming discusses each point more specifically in thefollowing.

1. Oil consumption
Both the operator and mechanic should know what the general history of oil consumption during the life of the engine has been.

A possible danger signal concerning engine health is a definite increase in oil consumption during the recent 25 to 50hr of flight time. The oil screens and filter should be carefully observed for signs of metal.

Maintenance should also take a good differential compression check at this time. The mechanic should look in the cylinders with a gooseneck light or a borescope to detect any unusual conditions in the combustion chamber. If you haven't looked at the air filter lately, it would be a good idea to carefully inspect it for wear and proper fit. This is all the more important when operating in dusty areas, and definitely could be a cause of increased oil consumption.

2. Engine history and calendar age
If an engine has been basically healthy throughout its life, this would be a favourable factor in continuing to operate it as the engine approached high time.

Alternately, if it has required frequent repairs, the engine may not achieve its expected normal life. A logbook inspection would reveal any accumulative record of engine repairs.

Another important aspect of an engine's history would be its calendar age. Engine flight time and calendar age are equally important to the operator. Engines flown infrequently do tend to age or deteriorate more quickly than those flown on a regular basis. Therefore, Lycoming recommends both an operating hour limit and a calendar year limit between overhauls. Service Instruction 1009gives these recommendations, but other items in this checklist will help to determine if an overhaul or engine exchange is needed before the engine reaches these recommended limits.

3. Pilot's opinion of the engine
The pilot's opinion of the powerplant based on his or her experience operating it is another important point in our checklist. The pilot will have an opinion based on whether it has been a dependable powerplant, and whether or not he or she has confidence in it. If the pilot lacks confidence in an engine as it approaches the manufacturer's recommended limits, this could be a weighty factor in the decision to continue flying or to overhaul it. The pilot should consult with maintenance personnel concerning their evaluation of the condition of the powerplant.

4. Operation
The basic question here would be how the engine has been operated the majority of its life. Some engines operating continuously at high power, or in dusty conditions, could have a reduced life. Likewise, if the pilot hasn't followed the manufacturer's recommendations on operation it may cause engine problems and reduce the expected life. This becomes a more critical influence on a decision in single-engine aircraft, and also for single- or twin-engine planes flown frequently at night or in IFR conditions.

5. Maintenance
Good maintenance should aid in achieving maximum engine life; alternately, poor maintenance tends to reduce the expected life. Lycoming says it has noticed that among the powerplants going back to the factory for rebuild or overhaul, the smaller engines in general have had less care and attention, and in a number of instances have been run until something goes wrong. The higher-powered engines have generally had better maintenance and show evidence that the operators do not wait until something goes wrong, but tend to observe the manufacturer's recommended operating hour or calendar limits to overhaul. The engine logbook should reflect the kind of maintenance provided the engine or engines. The mechanic who regularly cares for the engine will usually have an opinion about its health.

6. What does the oil filter tell?
Clean oil has consistently been an important factor in aiding and extending engine life. A good full flow oil filter has been a most desirable application here. When the filter is changed, open it and carefully examine for any foreign elements, just as is accomplished at oil change when the engine oil screen is examined for the same purpose. Just as the spark plugs tell a story about what is going on in the engine, so do the engine oil screen and the external oil filter tell a story about the health of an engine. Whether the engine is equipped with an oil filter or just a screen, oil changes should be accomplished in accordance with the manufacturer's recommendations. These oil changes should have been recorded in the engine logbook.

If oil is analyzed, it should be done at each oil change in order to establish a baseline. Analysis is a tool which only gives useful information when a dramatic departure from the established norm occurs.

7. Compression checks
What has been the trend in compression in at least the last two differential compression checks? The differential compression check is the more reliable type and should be taken on a warm engine. If the differential check reveals 25percent loss or more, then trouble may be developing. A compression test should be made anytime faulty compression is suspected, anytime the pilot observes a loss of power in flight, when high oil consumption is experienced, or when soft spots are noticed while hand pulling the prop.

Many mechanics do a compression check at each oil change, and it is also considered part of the 100‎hr engine inspection and the annual inspection. Most experienced mechanics feel that the differential compression check is best used to chart a trend over a period of flight hours. A gradual deterioration of charted compression taken during maintenance checks would be a sound basis for further investigation.

8. Spark plugs
The spark plugs, when removed and carefully observed, tell you what has been happening in the cylinders during flight, and can be a helpful factor in deciding what to do with a high time engine:

  1. Copper run out and/or lead fouling means excessiveheat.
  2. Black carbon and lead bromide may indicate low temperatures, the type of fuel being used, and possibly excessive richness of fuel metering at idle.
  3. Oil-fouled plugs may indicate that piston rings are failing to seat, or excessive wear is taking place.
  4. The normal colour of a spark plug deposit is generally brownish grey.
  5. In high compression and supercharged engines, a cracked spark plug porcelain will cause or has been caused by pre-ignition.

9. Engine manufacturer recommended overhaul life
Service Instruction 1009 is the Textron Lycoming published recommendation for operating hour and calendar year limits until engine overhaul as they apply to each specific engine model. The amount of total operating time on an engine will be a basic factor in any decision to either continue flying, change, top, or major overhaul the powerplant. Operators should be reminded, however, that the hours of service life shown in the service instruction are recommendations for engines as manufactured and delivered from the factory. These hours can normally be expected provided recommended operation, periodic inspections, frequent flights, and engine maintenance have been exercised in accordance with respective engine operator's manuals.

If an operator chooses to operate an engine beyond the recommended limits, there are factors to consider. The cost of overhaul is likely to be greater as engine parts continue to wear, and the potential for failure may also increase.

Operators who have top overhauled their engine at some point in the engine life invariably want to know if this extends the life of the engine. This is an important question. The chances are that if the operator applies the checklist we have been discussing and comes up with favourable answers to these questions about his engine, he can probably get the hours desired-with only a few exceptions. But a top overhaul does not increase the official life or TBO of the engine.

Lycoming says it is surprised from time to time by owners who say they top overhauled their engine at some point less than the major overhaul life for no reason other than somebody said it was a good idea. Unless the manufacturer recommends it, or there is a problem requiring a top overhaul, this is a needless cost. If the engine is healthy and running satisfactorily, then leave it alone! One other point deserves attention here: there is no substitute or cheap route to safety in the proper maintenance or correct overhaul of an engine.

Apply all of these basic nine points concerning your engine or engines and then make a decision whether to top overhaul, major overhaul, exchange engines, or continue flying.

Additional resource: http://www.lycoming.textron.com/.



Back Shop: Industry Insights

by Bart J. Crotty. This article was previously published in AviationMaintenance magazine and is reprinted with permission.

Personal, subjective approaches to affect safety emphasize addressing self-preservation, professional pride and concern for public and other workers' well-being. Another approach could be instilling a respect for aviation objects or equipment used by worker groups-namely, adopting a Zen Buddhist reverence for aircraft.

Round the Bend, a1951 novel by Nevil Shute(1899-1960), pays homage to a mystical aircraft ground engineer(mechanic). The story is about a struggling English pilot/owner, Tom Cutter, and his small airline operating from Bahrain and the relationships with his first-rate, ascetic Eurasian chief mechanic, Connie. Connie has a special intuitive understanding of the aircraft he works on-all to the increased reliability and safety of the airline's operations. Others in the polyglot company eventually grow in self-development from Connie's caring, reverent, and positive example. The book title refers to the phrase, now out of vogue, of someone gone too far, losing their origins; in this case, it means "gone native", to be exact.

Years back, I acquired an interest in Nevil Shute, whose aviation background(airship and aircraft designer) led him to write a few fictional and non-fictional aviation works, Slide Rule and No Highway respectively. His other books, include A Town Called Alice and Requiem for a Wren.

My aviation career began as an aircraft mechanic and I've never lost that foundation and pride, although I've acquired other experiences/qualifications in flight operations, training, regulations, security, engineering design, human factors(HF), accident investigation, and safety. I've never come across an aviation novel that focuses more on an aircraft mechanic's plight or gives personal insights to maintenance than Round the Bend.

In my being ever-open to unusual or unorthodox ways to gain workers' attention and appeal to one's sensibilities to further aviation safety, the notion recently struck about "respect or reverence" as a construct applied to aircraft themselves. If pilots, mechanics, air traffic controllers, etc., developed more genuine respect for their flying machines, animating or personifying them so to speak, giving them some degree of human/spiritual consideration, then that respect would result in more care given in the operation, maintenance, control and handling of aircraft.

Even before the infamous Aloha Airlines B-737 upper fuselage peel-back accident of 1988, I began, and continue today, to study and champion efforts to apply HF maintenance/inspection training and awareness to prevent or reduce maintenance personnel or management error. On recent charter operator safety/security auditing trips to India and Africa, I found myself giving unplanned, spontaneous "Dutch uncle" type talks to small groups of pilots/mechanics, trying to motivate them to think and act in terms of safety. But it never dawned on me to emphasize the internalizing or feeling aspect of safety-that is, exploiting an emotional or spiritual basis for safety. Granted, it won't apply or take root with everyone's character/values, but surely there are many who would be affected and would accept and adopt this approach to some degree.

I do much of my consulting, brainstorming or contemplative thinking on return flights of business trips and the novel Round the Bend surfaced in my memory at 36000ft. Sure enough, later at home, I found I still had my old yellowed paperback copy.

I've now decided to include this Zen Buddhism approach-inculcating a respectful/spiritual base to aviation safety-in my future HF and safety training sessions for maintenance and ramp service personnel. A typical application could be to hold two one-hour training sessions wherein the basic principles of Zen Buddhism are introduced, and then show and explain the potential resulting benefits. Namely, increased work area safety awareness; more concern for fellow workers' well-being; reduction of personal and workplace stress; and new or increased respect/reverence for aircraft, tools and equipment, etc. This is no attempt to proselytize or recruit new believers; it is just a new way to raise the awareness to increase overall aviation safety.

Admittedly, not many owners/management will pioneer and embrace this different approach to improve their safety programs. And like many training efforts, it would be difficult to justify or show post-training benefits or improvements in concrete terms.

Just the phrase ‘‘ZenBuddhism'' could be enough to send many in management running in the opposite direction.

I'll leave answering the sarcastic last sentence to Round the Bend's main character, Tom Cutter: "People are saying I've been out East too long and I've gone round the bend. Maybe I have, but then I think that being round the bend is the best place to be..."

One of Zen Buddhism's tenets is to piously ponder a question(koan) that has no right or wrong, or rather no definitive answer. Now, besides considering the Zen way to improve aviation worker safety, one has two other things to ponder about: possibly being round the bend themselves, and then contemplating that idea.

End notes:

  1. Zen and the Art of Motorcycle Maintenance, 1974, by RobertM.Pirsig surely gave me a nudge in the direction of aircraft maintenance; however, the book has no strong foundation in Zen or other schools of Buddhism. It's a non-fictional account of a modern man trying to find his inner sense of caring and feeling in a doubtful world.
  2. My article, Zen and the Art of Aircraft Maintenance, appeared in the monthly aviation publication Aviation Maintenance, Sept.2007issue.

About the author:
Bart J. Crotty is an airworthiness/maintenance/flight operations/safety/security consultant, expert witness, writer, and the maintenance HF chairman for the International Society of Air Safety Investigators. He resides in Springfield, Virginia. Readers can reach him at bjcrotty@verizon.net.



Fatigue Risk Management System for the Canadian Aviation Industry: Fatigue Management Strategies for Employees(TP14573E)

This is the second in a seven-part series highlighting the work of the Fatigue Risk Management System(FRMS) Working Group and the various components of the FRMS toolbox. This article deals with TP14573E, a workbook designed for Transport Canada Civil Aviation employees. We encourage our readers to consult the complete toolbox documentation by visiting www.tc.gc.ca/eng/civilaviation/standards/sms-frms-menu-634.htm. -Ed.

Why a training program on fatigue risk management?

Transport Canada is committed to improving aviation safety through the management of fatigue-related risks. To this end, a set of tools was developed to support the Canadian aviation industry in implementing a fatigue risk management system(FRMS) within safety management systems(SMS). An important part of an FRMS consists in training all employees in the management of fatigue as a safety hazard. To achieve this goal, the tools developed include various training materials that are designed to meet the business needs of participating organizations and the skills-development needs of their employees in relation to fatigue risk management.

Managing human resources has always been a demanding task, and now, more than ever, industry must acknowledge the unique needs of employees who work outside the Monday-to-Friday, 9-to-5 schedule. Non-traditional work-schedule designs have benefits for employers and employees. However, decisions made without thorough knowledge of the safety, family, or social impacts of such hours could result in shift patterns that compromise any potential benefits. Appropriate and efficient management of the workforce is crucial to meeting the demands of the Canadian Aviation Regulations (CARs) and ensuring high levels of work-site productivity.

What is the purpose of this workbook (TP 14573E)?

This workbook aims to provide the knowledge and skills to help you adopt appropriate fatigue-management strategies. More specifically, you will learn how to

  • monitor potential causes of fatigue and devise action plans to minimize their effects in accordance with company procedures;
  • identify personal warning signs of fatigue and appropriate countermeasures in accordance with workplace procedures to ensure that effective work capability and alertness are maintained;
  • make positive lifestyle choices to promote the effective long-term management of fatigue;
  • adopt and apply effective practices and countermeasures for combating fatigue; and
  • communicate your personal fatigue-management strategies to relevant people.

How to use this workbook?

This workbook involves a combination of theory and practical strategies related to both work and non-work situations. This study guide will be your reference during your training.

Exercises are provided throughout the workbook. Students are asked to demonstrate that they can apply the knowledge learned to everyday situations by completing the exercises provided in each chapter. Knowledge checks are also included at the end of each chapter to allow students to verify whether they need to review some of the content or not.

Will this program be assessed?

Depending on the training format chosen by your company, you may have to complete an assessment to receive a certificate of completion for this course. Your trainer or supervisor will inform you if an assessment process will be used and of its exact format. An assessment can take various forms, including the ones described below.

By completing the exercises in each chapter of the workbook, you may demonstrate that you are able to apply this learning to your individual work situation. This type of assessment may be endorsed by the assessor or your supervisor.

You may be asked to complete an assessment exercise to show that you have retained knowledge and acquired skills from this training. This type of assessment involves answering questions on the content of this workbook(similar to the exercises and knowledge checks).

Skill achievement may also be demonstrated by maintaining a candidate's log. This process requires you to record how you have applied the skills learned during the course in your specific work situation and daily life.

Working non-traditional hours-living in a 24-hour society
We live in a 24-hour society where many different work patterns have developed beyond the traditional Monday-to-Friday, 9-to-5 routine. An increasing proportion of the workforce is engaged in shift work and non-traditional schedules. Between 15 and 30percent of the workforce of industrialized countries is engaged in shift work. In Finland, 25percent of the working population are shift workers, while in Singapore that figure is closer to
32percent. In Canada, approximately 30percent of workers are employed in some form of shift work.

Working shifts or non-traditional hours involves more than just a work schedule. It is a way of life with a fundamental impact on not only work, but also sleep patterns and the management of health, family, and social lives. Research also indicates that shift work affects physical and mental health, as well as work performance.

Exercise 1. What are some of the personal difficulties that you or some of your co‎workers have experienced as a result of shift work or non-traditional working hours? ________________________________________________________
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What is fatigue?
Fatigue is an experience of physical or mental weariness that results in reduced alertness. For most people, the major cause of fatigue is not having obtained adequate rest or recovery from previous activities. In simple terms, fatigue largely results from inadequate quantity or quality of sleep. This is because both the quantity(how much) and the quality(how good) of sleep are important for recovery from fatigue and maintaining normal alertness and performance. Furthermore, the effects of fatigue can be made worse by exposure to harsh environments and prolonged mental or physical work.

Inadequate sleep(whether because of lack of quality or quantity) over a series of nights causes a sleep debt, which results in increased fatigue that can sometimes be worse than a single night of inadequate sleep. A sleep debt can only be repaid with adequate recovery sleep.

Working outside the Monday-to-Friday, 9-to-5 routine can limit the opportunity for sleep and recovery in each 24-hour period. Working outside this schedule can reduce the amount of sleep you get by between one and three hours per day. This is because these hours of work

  • limit the amount of time available for sleep; and
  • disrupt the body clock, which is programmed for activity during the day and sleep at night.

In addition to sleeping less, people who work non-traditional hours often obtain sleep of a lower quality.

In the current 24-hour, 7-day-a-week society, there are many reasons that workers do not obtain the quality or quantity of sleep that they require to be adequately rested. Some of these reasons are work-related and some are non-work related. Examples of work-related fatigue factors are

  • hours of work(especially night work, early-morning starts, and high total number of hours);
  • task demands or time pressures that do not allow for adequate breaks during shifts; and
  • working conditions that may compound fatigue(for example, heat stress and time pressures).

Examples of non-work-related fatigue factors include

  • undiagnosed or untreated sleep disorders; and
  • individual family or social factors that take priority over sleep.

Exercise 2. Identify at least two causes of work-related fatigue that have affected you during your working life.
________________________________________________________
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For more discussions, exercises, and case studies on topics such as symptoms of fatigue, sleep, or napping, visit
http://www.tc.gc.ca/media/documents/ca-standards/14573e.pdf.

Date modified:
2011-04-28