AERO 3020 EXAM 1 QUESTIONS AND VERIFIED
ANSWERS
What do failures result in - Answers - high cost in life, $$ and/or reputation
Why not preform a failure analysis - Answers - -failure has low impact
-failure occurs in low cost component
-failure is expected/planned
-failure is obvious
How many parts of a failure is there - Answers - 9
Which step has the most amount of people involved - Answers - 6
Step 1 - Answers - identify failure
step 2 - Answers - bring together team
step 3 - Answers - Preliminary examination failure
-Document part numbers, photograph parts, select samples, etc
Step 4 - Answers - collect foundational information related to failure
-includes engineering drawings, specifications, etc
step 5 - Answers - brainstorm
-5 whys, fishbone, etc
step 6 - Answers - investigate in order to remove as many proposed causes from the
root cause map.
-no destructive testing which is checking for cracks, dimesnsional inspection, check
coating thickness, residucal stress measurement, collect samples, prepare samples,
preform testing on similar parts
step 7 - Answers - test the root cause
-Preform stress analysis. Analysis of all evidence, formulation of conclusions,
preparation of report with recommendations. Documentation, analysis of all evidence,
eval nature of crack, wear evaluation
step 8 - Answers - Issue findings to all involved in investigation and solicit feedback
-non advocate review
step 9 - Answers - publish findings to community at large in order to share learnings
, 5W's and one H (kipling Method) - Answers - Who, What, Where, When, Why and often
How? This technique may not be used for root cause analysis per-se but is often used
to start the information gathering process (Step 4) of a failure analysis. Can't be
answered by a yes or no. Once completed a hypothesis can be generated.
the five whys - Answers - Cause and effect relationship associated with a problem. Says
why until root cause is highlighted.
Benefits: Simple, used to populate legs of more detailed analyses
Problems: Limited by investigators current knowledge, Inexperienced investigators can
highlight symptoms rather than lower-level root causes, results are not repeatable
(different causes for same problem), isolate single cause and exclude others
Ishikawa/Fishbone Diagram - Answers - cause and effect diagrams that are set-up to
highlight the possible causes of a specific event. Each of the causes are grouped into a
small number of major categories. Categories include equipment, process, people,
materials, environment, management, other categories can be substituted
BENEFITS: allow for rapid and comprehensive mapping of contributors to a particular
event
PROBLEMS:Inability to distinguish between necessary and sufficient causes of a
specific event. Necessary, the even cannot occur w/o that cause but the event is not
exclusive to the cause. Sufficient the event can only occur with only that cause, not
requiring any other causes to result in the event
why because - Answers - cause-and-effect analysis used in failures analysis which
offers the benefit of logical distinction between necessary and sufficient within a map of
cause and effect. Counterfactual test(CT), helps prove that a cause is necessary or not.
Casual sufficiency test(CST), show the identified causes result in event
Primary event - Answers - Circle, Basic events, malfunctions, or causes, with available
data from test results or failure analysis information.
Intermediate event - Answers - square, Identified fault or event, produced by
combination of other more basic causes: a "gate" input or output.
Underdeveloped event - Answers - hexagon, Events not pursued to determine more
basic faults, used mostly for information purposes; limit of fault tree resolution
Fault tree analysis - Answers - determining the root cause of a failure following
deductive reasoning paths complete with event, gate and transfer logic capabilities.
Primary bonds - Answers - Sting, metallic, ionic, covalent
secondary bonds - Answers - weak, hydrogen and van der waals
metallic bonds - Answers - a bond formed by the attraction between positively charged
metal ions and the electrons around them. Heavy and dense
ANSWERS
What do failures result in - Answers - high cost in life, $$ and/or reputation
Why not preform a failure analysis - Answers - -failure has low impact
-failure occurs in low cost component
-failure is expected/planned
-failure is obvious
How many parts of a failure is there - Answers - 9
Which step has the most amount of people involved - Answers - 6
Step 1 - Answers - identify failure
step 2 - Answers - bring together team
step 3 - Answers - Preliminary examination failure
-Document part numbers, photograph parts, select samples, etc
Step 4 - Answers - collect foundational information related to failure
-includes engineering drawings, specifications, etc
step 5 - Answers - brainstorm
-5 whys, fishbone, etc
step 6 - Answers - investigate in order to remove as many proposed causes from the
root cause map.
-no destructive testing which is checking for cracks, dimesnsional inspection, check
coating thickness, residucal stress measurement, collect samples, prepare samples,
preform testing on similar parts
step 7 - Answers - test the root cause
-Preform stress analysis. Analysis of all evidence, formulation of conclusions,
preparation of report with recommendations. Documentation, analysis of all evidence,
eval nature of crack, wear evaluation
step 8 - Answers - Issue findings to all involved in investigation and solicit feedback
-non advocate review
step 9 - Answers - publish findings to community at large in order to share learnings
, 5W's and one H (kipling Method) - Answers - Who, What, Where, When, Why and often
How? This technique may not be used for root cause analysis per-se but is often used
to start the information gathering process (Step 4) of a failure analysis. Can't be
answered by a yes or no. Once completed a hypothesis can be generated.
the five whys - Answers - Cause and effect relationship associated with a problem. Says
why until root cause is highlighted.
Benefits: Simple, used to populate legs of more detailed analyses
Problems: Limited by investigators current knowledge, Inexperienced investigators can
highlight symptoms rather than lower-level root causes, results are not repeatable
(different causes for same problem), isolate single cause and exclude others
Ishikawa/Fishbone Diagram - Answers - cause and effect diagrams that are set-up to
highlight the possible causes of a specific event. Each of the causes are grouped into a
small number of major categories. Categories include equipment, process, people,
materials, environment, management, other categories can be substituted
BENEFITS: allow for rapid and comprehensive mapping of contributors to a particular
event
PROBLEMS:Inability to distinguish between necessary and sufficient causes of a
specific event. Necessary, the even cannot occur w/o that cause but the event is not
exclusive to the cause. Sufficient the event can only occur with only that cause, not
requiring any other causes to result in the event
why because - Answers - cause-and-effect analysis used in failures analysis which
offers the benefit of logical distinction between necessary and sufficient within a map of
cause and effect. Counterfactual test(CT), helps prove that a cause is necessary or not.
Casual sufficiency test(CST), show the identified causes result in event
Primary event - Answers - Circle, Basic events, malfunctions, or causes, with available
data from test results or failure analysis information.
Intermediate event - Answers - square, Identified fault or event, produced by
combination of other more basic causes: a "gate" input or output.
Underdeveloped event - Answers - hexagon, Events not pursued to determine more
basic faults, used mostly for information purposes; limit of fault tree resolution
Fault tree analysis - Answers - determining the root cause of a failure following
deductive reasoning paths complete with event, gate and transfer logic capabilities.
Primary bonds - Answers - Sting, metallic, ionic, covalent
secondary bonds - Answers - weak, hydrogen and van der waals
metallic bonds - Answers - a bond formed by the attraction between positively charged
metal ions and the electrons around them. Heavy and dense
