CMRT Troubleshooting and Analysis Questions and Answers

Question 1

A technician is investigating a recurring failure on a hydraulic power unit.
After fixing the immediate symptom (a blown fuse), they use the '5 Whys' technique to find the root cause.
The analysis proceeds as follows: 1.
Why did the fuse blow? - The motor overloaded. 2.
Why did the motor overload? - The pump was working too hard. 3.
Why was the pump working too hard? - The fluid was too thick (viscosity too high).
What is the MOST logical fourth 'Why' question to ask in this analysis?

Accepted Answer

Why was the incorrect fluid used or why has the fluid degraded?

Answer

Why was the system pressure so high?

Answer

Why did the motor's thermal overload not trip first?

Answer

Why was the pump shaft worn out?

Question 2

A team is conducting a Failure Modes and Effects Analysis (FMEA) on a critical piece of equipment. What is the primary goal of this type of analysis?

Accepted Answer

To proactively identify potential failure modes and their consequences.

Answer

To reactively document failures after they have occurred.

Answer

To prioritize maintenance work orders based on cost.

Answer

To calculate the mean time between failures (MTBF) for the asset.

Question 3

When troubleshooting a pneumatic actuator that is moving too slowly, a technician has confirmed that the air pressure supplied to the directional control valve is correct. Which of the following is the MOST likely cause of the slow movement?

Accepted Answer

A flow control valve is incorrectly adjusted or an exhaust silencer is clogged.

Answer

The compressor is overheating.

Answer

The FRL (Filter, Regulator, Lubricator) unit has been removed.

Answer

The cylinder piston seals are completely blown.

Question 4

A maintenance team is using a Fishbone (Ishikawa) diagram to analyze the root cause of frequent bearing failures on a fan. Which of the following would be an appropriate category, or 'bone,' to use on this diagram?

Accepted Answer

Methods

Answer

Return on Investment

Answer

Predictive Maintenance Schedule

Answer

Failure Code

Question 5

A technician reviews an oil analysis report for a gearbox that shows a sudden, significant increase in the iron (Fe) and copper (Cu) particle count, while silicon (Si) levels remain normal. What is the MOST likely interpretation of these results?

Accepted Answer

There is accelerated wear of internal steel gears and bronze bushings.

Answer

The gearbox is contaminated with dirt and sand from the environment.

Answer

The wrong type of lubricant was added during a top-off.

Answer

The oil has exceeded its useful life due to oxidation.

Question 6

During troubleshooting of a hydraulic system that is operating erratically, the technician notices the hydraulic fluid in the reservoir appears milky or foamy. This is a primary indicator of what type of contamination?

Accepted Answer

Air or water entrainment

Answer

Varnish and sludge buildup

Answer

Excessive particulate matter

Answer

Cross-contamination with gear oil