Basic Tools for Process Improvement Module 9 RUN CHART RUN CHART 1 Basic Tools for Process Improvement What is a Run Chart? A Run Chart is the most basic tool used to display how a process performs over time. It is a line graph of data points plotted in chronological order—that is, the sequence in which process events occurred. These data points represent measurements, counts, or percentages of process output. Run Charts are used to assess and achieve process stability by highlighting signals of special causes of variation (Viewgraph 1). Why should teams use Run Charts? Using Run Charts can help you determine whether your process is stable (free of special causes), consistent, and predictable. Unlike other tools, such as Pareto Charts or Histograms, Run Charts display data in the sequence in which they occurred. This enables you to visualize how your process is performing and helps you to detect signals of special causes of variation. A Run Chart also allows you to present some simple statistics related to the process: Median: The middle value of the data presented. You will use it as the Centerline on your Run Chart. Range: The difference between the largest and smallest values in the data. You will use it in constructing the Y-axis of your Run Chart. You can benefit from using a Run Chart whenever you need a graphical tool to help you (Viewgraph 2) Understand variation in process performance so you can improve it. Analyze data for patterns that are not easily seen in tables or spreadsheets. Monitor process performance over time to detect signals of changes. Communicate how a process performed during a specific time period. 2 RUN CHART Basic Tools for Process Improvement What is a Run Chart? A line graph of data points plotted in chronological order that helps detect special causes of variation. RUN CHART VIEWGRAPH 1 Why Use Run Charts? • Understand process variation • Analyze data for patterns • Monitor process performance • Communicate process performance RUN CHART RUN CHART VIEWGRAPH 2 3 Basic Tools for Process Improvement What are the parts of a Run Chart? As you can see in Viewgraph 3, a Run Chart is made up of seven parts: 1. Title: The title briefly describes the information displayed in the Run Chart. 2. Vertical or Y-Axis: This axis is a scale which shows you the magnitude of the measurements represented by the data. 3. Horizontal or X-Axis: This axis shows you when the data were collected. It always represents the sequence in which the events of the process occurred. 4. Data Points: Each point represents an individual measurement. 5. Centerline: The line drawn at the median value on the Y-axis is called the Centerline. (Finding the median value is Step 3 in constructing a Run Chart.) 6. Legend: Additional information that documents how and when the data were collected should be entered as the legend. 7. Data Table: This is a sequential listing of the data being charted. How is a Run Chart constructed? Step 1 - List the data. List the data you have collected in the sequence in which it occurred. You may want to refer to the Data Collection module for information on defining the purpose for the data and collecting it. Step 2 - Order the data and determine the range (Viewgraph 4). To order the data, list it from the lowest value to the highest. Determine the range—the difference between the highest and lowest values. Step 3 - Calculate the median (Viewgraph 4). Once the data have been listed from the lowest to the highest value, count off the data points and determine the middle point in the list of measurements—the point that divides the series of data in half. If the count is an odd number, the middle is an odd number with an equal number of points on either side of it. If you have nine measurements, for example, the median is the fifth value. If the count is an even number, average the two middle measurements to determine the median value. For example, for 10 measurements, the median is the average of the fifth and sixth values. To determine the average, just add them together and divide by two. 4 RUN CHART Basic Tools for Process Improvement Parts of a Run Chart TEAM BATTING AVERAGE (1994) 1 0.360 5 Batting Average 0.350 2 0.340 Centerline = .3325 0.330 Durham Bulls’ Team Batting Avg. recorded on Mon. of every week during the 1994 season by Rob Jackson, team statistician 0.320 0.310 0.300 4 October 15, 1994 0.290 0 1 2 3 4 5 6 7 3 WEEK 1 AVG 2 3 4 5 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 6 Weeks of the Season 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 300 333 325 332 340 345 350 340 341 345 349 354 350 344 333 325 318 1 TITLE 3 X-AXIS 5 CENTERLINE 2 Y-AXIS 4 DATA POINT 6 LEGEND 305 298 306 310 315 310 318 7 7 DATA TABLE RUN CHART VIEWGRAPH 3 How to Construct a Run Chart Step 2 - Order data & determine range Step 3 - Calculate the median RANK AVG RANK AVG RANK AVG 1 .298 9 .318 17 .341 2 .300 10 .325 18 .344 3 .305 11 .325 MEDIAN: 19 .345 4 .306 12 .332 (.332 + .333) / 2 20 .345 5 .310 13 .333 = .3325 21 .349 6 .310 14 .333 22 .350 7 .315 15 .340 23 .350 8 .318 16 .340 24 .354 RANGE: .354 - .298 = 0.56 RUN CHART RUN CHART VIEWGRAPH 4 5 Basic Tools for Process Improvement Now let’s continue with the remaining steps (Viewgraph 5). Step 4 - Construct the Y-Axis. Center the Y-Axis at the median. Make the Y-axis scale 1.5 to 2 times the range. Step 5 - Draw the Centerline. Draw a horizontal line at the median value and label it as the Centerline with its value. The median is used as the Centerline, rather than the mean, to neutralize the effect of any very large or very small values. Step 6 - Construct the X-axis. Draw the X-axis 2 to 3 times as long as the Y-axis to provide enough space for plotting all of the data points. Enter all relevant measurements and use the full width of the X-axis. NOTE: One of the strengths of a Run Chart is its readability, so don't risk making it harder to interpret by putting too many measurements on one sheet. If you have more than 40 measurements, consider continuing the chart on another page. Step 7 - Plot the data points and connect them with straight lines. Step 8 - Provide a Title and a Legend. Give the chart a title that identifies the process you are investigating and compose a legend that tells: The period of time when the data were collected The location where the data were collected The person or team who collected the data How do we interpret a Run Chart? Interpreting a Run Chart requires you to apply some of the theory of variation. You are looking for trends, runs, or cycles that indicate the presence of special causes. But before we examine those features of Run Charts, a word about variation. Expect to see it. Just remember that process improvement activities are expected to produce positive results, and these sometimes cause trends or runs, so the presence of special causes of variation is not always a bad sign. A Trend signals a special cause when there is a sequence of seven or more data points steadily increasing or decreasing with no change in direction. When a value repeats, the trend stops. The example in Viewgraph 6 shows a decreasing trend in lower back injuries, possibly resulting from a new "Stretch and Flex" exercise program. When your Run Chart shows seven or more consecutive ascending or descending data points, it is a signal that a special cause may be at work and the trend must be investigated. 6 RUN CHART Basic Tools for Process Improvement How to Construct a Run Chart Step 4 - Construct the Y-axis Step 5 - Draw the Centerline Step 6 - Construct the X-axis Step 7 - Plot and connect the data points Step 8 - Provide a title and a legend RUN CHART VIEWGRAPH 5 Trend Example MONTHLY REPORTED BACK INJURIES 40 Stretch & Flex Started: January 1993 Number of Injuries 36 32 28 24 Centerline = 23 20 16 12 8 4 0 J F M A M J J A S O N D J F M A M J J A S O N D 1992 - 1993 Signal of special cause variation: 7 or more consecutive ascending or descending points RUN CHART RUN CHART Data taken from OSHA Reports and CA-1 forms by Bob Kopiske. Compiled and charted on 15 January 1994. VIEWGRAPH 6 7 Basic Tools for Process Improvement A Run consists of two or more consecutive data points on one side of the centerline. A run that signals a special cause is one that shows nine or more consecutive data points on one side of the centerline. In the example in Viewgraph 7, you can see such a run occurring between 15 and 28 March. Investigation revealed that new software was responsible for the increase in duplication. This was corrected on 29 March with the introduction of a software "patch." Whenever a data point touches or crosses the centerline, a run stops and a new one starts. When your Run Chart shows nine or more consecutive data points on one side of the centerline, it is an unusual event and should always be investigated. A Cycle, or repeating pattern, is the third indication of a possible special cause. A cycle must be interpreted in the context of the process that produced it. In the example in Viewgraph 8, a housing office charted data on personnel moving out of base housing during a four-year period and determined that there was an annual cycle. Looking at the 1992-1993 data, it's evident that there were peaks during the summer months and valleys during the winter months. Clearly, understanding the underlying reasons why a cycle occurred in your process enables you to predict process results more accurately. A cycle must recur at least eight times before it can be interpreted as a signal of a special cause of variation. When interpreting a cycle, remember that trends or runs might also be present, signaling other special causes of variation. NOTE: The absence of signals of special causes does not necessarily mean that a process is stable. Dr. Walter Shewhart suggested that a minimum of 100 observations without a signal is required before you can say that a process is in statistical control. Refer to the Control Chart module for more information on this subject. 8 RUN CHART Basic Tools for Process Improvement Run Example DUPLICATE MESSAGES Number of Messages 40 30 20 Centerline = 15 10 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 March 1994 - Weekdays only plotted Signal of special cause variation: 9 or more consecutive data points on the same side of the centerline Data taken from manual daily count of incoming messages, entered on checksheet by L. Zinke, NAVEUR Fleet Quality Office. RUN CHART VIEWGRAPH 7 Cycle Example HOUSING MOVE-OUTS Number of Units 40 30 20 Centerline = 10 10 0 J F M A M J J A S O N D J F M A M J J A S O N D 1992-1993 Signal of special cause variation: Repeating patterns RUN CHART RUN CHART Data from Housing Office records for 1992-93. Compiled and charted on 1 FEB 94 by Gail Wylie. VIEWGRAPH 8 9 Basic Tools for Process Improvement How can we practice what we've learned? The following exercises are provided to help you sharpen your skills in constructing and interpreting Run Charts. EXERCISE 1 has two parts based on this scenario: Maintenance personnel in a helicopter squadron were receiving complaints from within the squadron and from its external customers because of valve overhaul backlogs which kept some aircraft grounded. To overcome the complaints and satisfy their customers, they realized they needed to reduce valve overhaul time without lessening reliability. EXERCISE 1 - PART A: They collected data from their process for 14 days, placing their measurements in a table (Viewgraph 9). The table told them that it took them between 170 and 200 minutes to complete one valve overhaul. Although the workload assignment for the 14-day period was 20 overhauls, their process allowed them to complete only 1 per day. This meant that they were adding 6 valves to the backlog every 2 weeks. They decided to display their data in a Run Chart which they could analyze for signals of special cause variation. To do this, they put their data in numerical order and calculated the centerline as follows: 1 200 2 191 3 190 4 190 5 187 6 185 7 184 Centerline (184 + 183) / 2 = 183.5 8 183 9 175 10 175 11 175 12 174 13 173 14 170 Draw a Run Chart of the overhaul time for the 14 valves shown in Viewgraph 9. Viewgraph 10 is an answer key. 10 RUN CHART Basic Tools for Process Improvement EXERCISE 1A DATA Overhaul Times First 14 Valves VALVE 1st 2nd 3rd 4th 5th 6th 7th TIME 174 190 185 170 191 187 183 DAY 1 2 3 4 5 6 7 VALVE 8th 9th 10th 11th 12th 13th 14th TIME DAY 175 8 200 9 175 10 RUN CHART RUN CHART 173 11 184 12 190 13 175 14 VIEWGRAPH 9 11 Basic Tools for Process Improvement EXERCISE 1A RUN CHART First 14 Valves 210 Minutes 200 190 Centerline = 183.5 180 170 160 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Days Valve 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th Time Day RUN CHART 12 174 190 185 170 191 187 183 175 200 175 1 2 3 4 5 6 7 8 9 10 173 184 190 11 12 13 175 14 VIEWGRAPH 10 RUN CHART Basic Tools for Process Improvement In the Run Chart constructed from the data in Part A of Exercise 1 (Viewgraph 10), there are no patterns or indications of special causes of variation. However, it appears that the process is not meeting customers’ expectations in terms of the number of valves that can be repaired within a given period of time. The helicopter maintenance team realized that they needed to decrease the time required to overhaul each valve so that they could increase the number of overhauled valves produced. Using tools such as Flowcharts, Pareto Charts, and Cause-andEffect Diagrams, they analyzed their process and made some changes. RUN CHART 13 Basic Tools for Process Improvement EXERCISE 1 - PART B: The team collected data from the overhaul of the next 14 valves and placed them in a table (Viewgraph 11). The table told them that the new range of the overhaul process was 95 to 165 minutes. Perform the centerline calculation for the two sets of data. Viewgraph 12 is an answer key. Draw a new Run Chart showing the overhaul times for all 28 valves. Viewgraph 13 is an answer key. Interpret the Run Chart. As you plot the data for all 28 valves, answer these questions: What can we tell about the performance of this process? What has occurred? How do we know? 14 RUN CHART Basic Tools for Process Improvement EXERCISE 1B DATA Overhaul Times Second 14 Valves VALVE 15th 16th 17th 18th 19th 20th TIME 165 140 125 110 108 105 DAY 15 16 17 18 19 20 21st 100 21 VALVE 22nd 23rd 24th 25th 26th 27th 28th TIME 95 108 115 120 105 100 95 DAY RUN CHART RUN CHART 22 23 24 25 26 27 28 VIEWGRAPH 11 15 Basic Tools for Process Improvement EXERCISE 1B Centerline Calculations Old Process Starts 1 200 Ends 2 191 3 190 4 190 5 187 6 185 7 184 8 183 9 175 10 175 11 175 12 174 13 173 14 170 } Centerline (184 + 183)/2 = 183.5 New Process Starts 15 165 Ends 16 140 17 125 18 120 19 115 20 110 21 108 22 108 23 105 24 105 25 100 27 95 26 100 28 95 } Centerline (108 + 108)/2 = 108 RUN CHART VIEWGRAPH 12 EXERCISE 1B RUN CHART All 28 Valves 240 220 200 Centerline = 183.5 Minutes 180 160 140 120 Centerline = 108 100 80 60 0 1 2 3 4 5 6 7 8 2nd 190 2 3rd 185 3 RUN CHART 16 4th 170 4 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Days TREND Valve 1st Time 174 1 Day 9 5th 191 5 6th 187 6 7th 183 7 8th 175 8 9th 200 9 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd 24th 25th 26th 27th 28th 95 108 115 120 105 100 95 175 173 184 190 175 165 140 125 110 108 105 100 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 VIEWGRAPH 13 RUN CHART Basic Tools for Process Improvement Looking at Viewgraph 12, you can see that there are now two distinct processes, each with its own centerline. The Run Chart plotted in Viewgraph 13 clearly shows that the new process has significantly improved the throughput by reducing the valve overhaul time. RUN CHART 17 Basic Tools for Process Improvement EXERCISE 2: A team was tasked with reducing the time required to launch the ship's motor whaleboat during man-overboard drills. Their analysis identified starting the motor as the factor having the greatest affect on time to launch. The team collected data on the time, measured in minutes, required to start the motor during 10 drills using the current process. The data table they prepared is shown in Viewgraph 14. The team then brainstormed factors that might contribute to the amount of time it took the engine to start. Fuel injector fouling was cited numerous times. The team investigated and learned that the engine started promptly on four earlier occasions when the injectors were removed and cleaned or completely replaced. They then used a technique know as “the five whys” to investigate further: Q: Why were the injectors getting fouled? A: There was oil in the cylinders. Q: Why was there oil in the cylinders? A: The piston rings were worn. Q: Why were the piston rings worn? A: They were old and needed replacement. Q: Why weren't they replaced? A: Spare parts were not readily available. Q: Why weren't spare parts readily available? A: The engine manufacturer recently lost all stock of spare parts in a devastating fire. Parts will be available in about two months. The team was able to develop a plan for improvement based on the answers this method of inquiry produced. To deal with the fouling problem, they (1) initiated a schedule for cleaning or replacing the fuel injectors, (2) made long-term plans to replace the worn piston rings, and (3) reviewed the maintenance schedule to ensure that the rings would be replaced routinely at particular maintenance intervals. After these changes in the process were instituted, the team collected data on the next 10 drills. The data table they prepared is shown in Viewgraph 15. Draw a Run Chart of the data from the 20 drills. Don’t forget to perform the centerline calculations. An answer key is provided in Viewgraph 16. Interpret your Run Chart. Are there any signals of special cause variation? If so, what are they? 18 RUN CHART Basic Tools for Process Improvement EXERCISE 2 DATA Minutes to Start Engine First 10 Drills DRILL 1st 2nd 3rd 4th 5th TIME 15.3 12.1 14.4 16.8 17.3 DRILL 6th 7th 8th 9th 10th TIME 16.6 14.2 12.0 11.3 13.9 RUN CHART VIEWGRAPH 14 EXERCISE 2 DATA Minutes to Start Engine Second 10 Drills DRILL 11th 12th 13th 14th 15th TIME 8.1 7.6 7.2 5.1 4.4 DRILL 16th 17th 18th 19th 20th TIME 4.0 2.6 2.2 4.5 5.3 RUN CHART RUN CHART VIEWGRAPH 15 19 Basic Tools for Process Improvement EXERCISE 2 RUN CHART Minutes to Start Engine TREND 20 Minutes 15 Centerline = 14.3 10 5 0 Centerline = 4.2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Drill Drill 1 Time 15 .3 RUN CHART 20 2 3 12 .1 14 .4 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 16 .8 17.3 16 .6 14.2 12 .0 11.3 13 .9 8 .1 7.6 7.2 5 .1 4 .4 4.0 2.6 2.2 4.5 5.3 VIEWGRAPH 16 RUN CHART Basic Tools for Process Improvement When you interpret the Run Chart in Viewgraph 16, you’ll see that there is indeed a signal of a special cause of variation—a trend. This trend charts the dramatic reduction in the number of minutes required to start the engine during the second ten drills. The efforts of the team described in Exercise 2 were rewarded with an improvement in the process. RUN CHART 21 Basic Tools for Process Improvement REFERENCES: 1. Brassard, M. (1988). The Memory Jogger, A Pocket Guide of Tools for Continuous Improvement, pp. 30 - 35. Methuen, MA: GOAL/QPC. 2. Department of the Navy (November 1992). Fundamentals of Total Quality Leadership (Instructor Guide), pp. 6-52 - 6-56. San Diego, CA: Navy Personnel Research and Development Center. 3. Department of the Navy (September 1993). Systems Approach to Process Improvement (Instructor Guide), pp. 7-13 - 7-43. San Diego, CA: OUSN Total Quality Leadership Office and Navy Personnel Research and Development Center. 4. U.S. Air Force (Undated). Process Improvement Guide - Total Quality Tools for Teams and Individuals, pp. 52 - 53. Air Force Electronic Systems Center, Air Force Materiel Command. 22 RUN CHART What is a Run Chart? A line graph of data points plotted in VIEWGRAPH 1 chronological order that helps detect special causes of variation. RUN CHART RUN CHART Why Use Run Charts? • Understand process variation • Analyze data for patterns • Monitor process performance • Communicate process performance VIEWGRAPH 2 2 4 0.360 0.350 0.340 0.330 0.320 0.310 0.300 0.290 0 2 1 3 2 3 5 6 6 7 7 8 9 9 10 11 12 13 14 15 16 17 18 19 20 21 23 1 5 October 15, 1994 Durham Bulls’ Team Batting Avg. recorded on Mon. of every week during the 1994 season by Rob Jackson, team statistician Centerline = .3325 24 6 315 310 318 7 VIEWGRAPH 3 7 DATA TABLE 305 298 306 310 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Weeks of the Season 8 TEAM BATTING AVERAGE (1994) 4 3 5 22 Parts of a Run Chart 4 5 CENTERLINE 325 318 3 X-AXIS 6 LEGEND 350 344 333 1 TITLE 4 DATA POINT 300 333 325 332 340 345 350 340 341 345 349 354 2 Y-AXIS RUN CHART AVG WEEK 1 Batting Average 6 5 4 3 2 1 RANK .315 .310 .310 .306 .305 .300 .298 AVG 16 15 14 13 12 11 10 9 RANK .340 .340 .333 .333 .332 .325 .325 .318 AVG = .3325 (.332 + .333) / 2 MEDIAN: 24 23 22 21 20 19 18 17 RANK .354 .350 .350 .349 .345 .345 .344 .341 AVG How to Construct a Run Chart Step 2 - Order data & determine range Step 3 - Calculate the median 7 .318 RANGE: .354 - .298 = 0.56 VIEWGRAPH 4 8 RUN CHART How to Construct a Run Chart Step 4 - Construct the Y-axis Step 5 - Draw the Centerline Step 6 - Construct the X-axis Step 7 - Plot and connect the data points VIEWGRAPH 5 Step 8 - Provide a title and a legend RUN CHART RUN CHART 40 36 32 28 24 20 16 12 8 4 0 J Trend Example J A S O N D J J A S O N D Centerline = 23 VIEWGRAPH 6 Data taken from OSHA Reports and CA-1 forms by Bob Kopiske. Compiled and charted on 15 January 1994. F M A M J Stretch & Flex Started: January 1993 MONTHLY REPORTED BACK INJURIES F M A M J 1992 - 1993 Signal of special cause variation: 7 or more consecutive ascending or descending points Number of Injuries 40 30 20 10 0 0 RUN CHART 1 2 3 4 5 6 7 8 Run Example DUPLICATE MESSAGES 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Centerline = 15 VIEWGRAPH 7 Data taken from manual daily count of incoming messages, entered on checksheet by L. Zinke, NAVEUR Fleet Quality Office. March 1994 - Weekdays only plotted Signal of special cause variation: 9 or more consecutive data points on the same side of the centerline Number of Messages 40 30 20 10 0 RUN CHART J F M A M J S O N D J F M A M J HOUSING MOVE-OUTS A A S O N D Centerline = 10 VIEWGRAPH 8 Data from Housing Office records for 1992-93. Compiled and charted on 1 FEB 94 by Gail Wylie. J Cycle Example J 1992-1993 Signal of special cause variation: Repeating patterns Number of Units EXERCISE 1A DATA 1st 2nd 3rd 4th 5th 187 6 6th 183 7 7th Overhaul Times First 14 Valves VALVE 191 5 VIEWGRAPH 9 14 170 4 13 185 3 12 190 2 11 174 1 10 TIME DAY 9 9th 10th 11th 12th 13th 14th 200 175 173 184 190 175 8 VALVE 8th TIME 175 DAY RUN CHART 210 200 190 180 170 160 RUN CHART Minutes 0 2 3 5 6 7 8 9 10 11 First 14 Valves 4 12 13 14 EXERCISE 1A RUN CHART 1 Days Valve 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Time 174 190 185 170 191 187 183 175 200 175 173 184 190 175 Day Centerline = 183.5 VIEWGRAPH 10 EXERCISE 1B DATA Overhaul Times Second 14 Valves VALVE 15th 16th 17th 18th 19th 20th 21st TIME 165 140 125 110 108 105 100 DAY 15 16 17 18 19 20 21 VIEWGRAPH 11 VALVE 22nd 23rd 24th 25th 26th 27th 28th TIME 95 108 115 120 105 100 95 DAY 22 23 24 25 26 27 28 RUN CHART 2 191 18 120 EXERCISE 1B 5 187 6 185 20 110 7 184 21 108 8 183 22 108 9 175 23 105 10 175 24 105 } Centerline (108 + 108)/2 = 108 19 115 Centerline (184 + 183)/2 = 183.5 } 17 125 4 190 25 100 11 175 26 100 12 174 Centerline Calculations 3 190 Old Process Starts 1 200 16 140 New Process Starts 15 165 RUN CHART 13 173 27 95 Ends 14 170 Ends 28 95 VIEWGRAPH 12 240 220 200 180 160 140 120 100 80 60 0 2nd 3rd 190 185 2 3 RUN CHART Valve 1st Time 174 Day 1 1 2 4th 170 4 TREND Minutes 6th 187 6 4 5 7th 183 7 6 8th 175 8 7 9 11 12 13 14 15 Days 16 17 18 20 21 22 23 24 25 Centerline = 183.5 19 27 28 Centerline = 108 10th 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th 21st 22nd 23rd 24th 25th 26th 27th 28th 175 173 184 190 175 165 140 125 110 108 105 100 95 108 115 120 105 100 95 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 10 All 28 Valves 8 9th 200 9 26 EXERCISE 1B RUN CHART 3 5th 191 5 VIEWGRAPH 13 EXERCISE 2 DATA TIME DRILL 6th 15.3 1st 14.2 7th 12.1 2nd 12.0 8th 14.4 3rd 11.3 9th 16.8 4th 13.9 10th 17.3 5th Minutes to Start Engine First 10 Drills DRILL 16.6 VIEWGRAPH 14 TIME RUN CHART EXERCISE 2 DATA TIME DRILL 16th 8.1 11th 2.6 17th 7.6 12th 2.2 18th 7.2 13th 4.5 19th 5.1 14th 5.3 20th 4.4 15th Minutes to Start Engine Second 10 Drills DRILL 4.0 VIEWGRAPH 15 TIME RUN CHART 20 15 10 5 1 1 0 Drill 15 .3 RUN CHART Time Minutes 2 2 5 7.6 17 18 4 .4 14 5 .1 13 16 7.2 12 15 Centerline = 14.3 14 12 13 11 11 10 10 9 9 13 .9 8 8 11.3 7 7 12 .0 6 6 14.2 Drill 5 16 .6 8 .1 17.3 19 15 4.0 17 2.2 4.5 18 5.3 19 Centerline = 4.2 2.6 16 20 TREND EXERCISE 2 RUN CHART 4 16 .8 4 Minutes to Start Engine 3 3 12 .1 14 .4 20 VIEWGRAPH 16