Category Nuances for mechanical_failure:

• unusual,
• random,
• internal,
• unforeseeable,
• actual,
• potential,
• unforeseen,
• undesirable,
• external,
• unplanned,
• uncontrollable,
• immediate,
• unpredictable,
• sudden,

Simple Categories for mechanical_failure:

• event,
• control,
• cause,
• circumstance,
• circumstances,
• situation,