Defining Condition Limits—Exercises

Main Exercise

Purpose: The purpose of this lesson is to learn how to define condition based maintenance.

Condition Monitoring - Tyre Tread Depth

Purpose: The purpose of this exercise is to learn how to register a maintenance plan based on condition monitoring.

The rule says that the landing wheel should be replaced when tyre tread depth is less than 3 millimeters. If the tread depth is less than 1 millimeter it is critical. Normal tread depth of a new tyre is 20 millimeters. The wheel should also be replaced if tread depth is reduced by more than 4 millimeters between two consecutive measurements. You need a Tread Depth Gauge to do the measurement which should be done every 4 weeks. 

An instruction for wheel replacement has been registered in a previous lesson, the operation number is n032212. An instruction (nX32213) on how to do the tyre tread check, will be defined in this exercise.

Windows:
Condition Monitoring Program
Instruction

Steps: To complete this exercise, perform the following steps.

  1. Open the Condition Monitoring Program window and query (F3) for your wheel, Part Number X32WHE7002, Rev n.
  2. Click the Condition Limit tab and create a new record (F5).
  3. Place cursor in the Condition Category field and use the Zoom function to create a new Condition Category called nTYRE.
  4. Use this category, and then specify Condition Code TREAD - Tread depth.
  5. Enter Standard Value at 20mm and specify Warning Limit Min. to 3 millimeters and Danger Limit Min. to 1 millimeter.
  6. Specify the Change Limit to 4 millimeter and Measure Frequency to 4 weeks.
  7. Optionally, you can enter additional information on the condition limit in the Task Remark field. When a task is created for the interval maintenance, this information will be transferred to the Task Remark field of the corresponding task record on the maintenance order.
  8. Save the information (F12).
  9. Click the Instructions tab and select Condition Category nTYRE and Condition Code TREAD.
  10. Then you are ready to define the instruction for tread measurement.
  11. Click the Operations tab.
  12. Create new record (F5) and specify a new operation for the tread depth measurement. Specify Operation Number n032213 of Type XCHK on your Wheel Assy revision "n". Specify Location, Strategy and Competency requirement of a mechanics for 0.2 hours.
  13. Specify Product Number 7X7 and Model Number X747-90n.
  14. Specify Function Number 3200, Sub Function 3220 and Bottom Level 3224 (Tyre)
  15. Double-click on the Work Description field and enter a brief description on how to measure the tread depth by using a depth gauge. Save the information (F12).
  16. Click the Tools and Facilities tab, create new record (F5) and specify the Tread Depth Gauge for 0.2 hours. Save the information (F12).
  17. Then you have to connect the instruction for wheel replacement.
  18. Open the Instruction window and query (F3) for Operation Number n032212.
  19. Click the Connect Task Codes tab and then click the Condition Limit sub tab and connect this instruction by specifying Cond Category nTYRE and Cond Code TREAD.
  20. Save the information (F12).
  21. Re-open the Condition Monitoring Program window and click the Instructions tab. 
  22. Refresh the information and verify that there are 2 operations attached to this condition measurement, one for doing the measurement and one for replacing the wheel when limits are exceeded.