Reference no: EM132281733

Minitab Reliability Assignment -

The Scenario -

The nose-wheel landing system of a commuter jet contains two critical components: A shock absorber (Component A) and bearing assembly (Component B). A failure of either component is considered to constitute a failure of the landing system, even though a landing may still be carried out. The manufacturer has recommended that component A should be overhauled or replaced at the end of its design life (?? = 97.5%). Component A may be overhauled up to a maximum of four (4) times before it should be discarded and replaced by a new part. Component B cannot be overhauled and needs to have a hard-time replacement strategy applied. To overhaul or replace either component, the aircraft will be out of service for 1 day. The manufacturer is currently undertaking accelerated life-cycle testing with the airline to determine a valid and cost effective maintenance and replacement strategy for both Components A and B.

Attached in electronic form is a Microsoft Excel® spreadsheet containing time-to-failure data for the landing gear assembly. This source of this data is accelerated life-cycle testing. The samples 2 of data contained in the spreadsheet may be considered partially complete and partially censored. The time- to-failure has been expressed in cycles, where one cycle represents a single landing.

This particular aircraft operator's policy is to operate a critical component up to a time where it can be demonstrated that the component reliability falls below 97.5%. This is of course for those critical items that are not covered by aircraft maintenance regulations and air directives. The airline would be very keen to see a methodology developed that can assist it in identifying age-related failure rate profiles so that it can aim towards optimum maintenance policies.

You (as a maintenance engineer) have been asked to develop a methodology and analyse the attached data in order to answer the following questions:

Assignment Sections -

1. Methodology & Approach

Describe the methodology that you would use to address the problem - 'to determine a valid and cost effective maintenance and replacement strategy for both components A & B'.

You will need to justify your main analysis technique - Weibull analysis, along with its strength and limitation.

2. Data Visualisation

Perform data visualisation on the dataset. Extract and describe any key information that you can find.

3. Weibull Analysis

Conduct Weibull analysis for the two critical components. You will need to present:

- Weibull probability plots

- Reliability plots R(t)

- Cumulative failure plots F(t)

- Failure rate plots λ(t)

Describe your plots and then calculate the mean cycles to failure of each critical component under different overhaul scheme. You may choose any statistical package to perform this analysis, but using Minitab 17 is recommended. You may also want to first study the commands in Minitab by clicking on Help → Help → Type 'parametric distribution analysis' in the Search tab.

4. Plot and describe the failure rate behaviour of the components as a function of age (hint: the bathtub curve).

5. Maintenance Strategy:

Use the cost information stated below to construct a cost model to identify the best maintenance strategy for both critical components (component A and B). Hence, determine the maintenance cost over 20,000 landing cycles.

Cost Information:

• Cost to replace a brand new shock absorber = $10,000.
• Cost to overhaul the shock absorber for the first time = $4,000.
• Cost to overhaul the shock absorber for the second time = $4,000.
• Cost to overhaul the shock absorber for the third time = $3,000.
• Cost to overhaul the shock absorber for the fourth time = $3,000.
• Cost to replace a brand new bearing assembly = $10,000.
• Cost associated with loss of aircraft availability = $18,000 per day.

6. Format

The document represented by each group must be in proper report format. Each team member should treat themselves as an engineering consultant, reporting on the essential findings (with analysis) to their manager. An abstract, introduction, chapter headings, sub- chapters, conclusion, and appendix should be included in the final report.