Accident Investigation and Analysis

BLRs Safety Training Presentations

11006115 Copyright Business & Legal Reports, Inc.

11006115 Copyright Business & Legal Reports, Inc.

Accident and Incident Investigation

Objectives of this Section

To define the reasons for investigating accident and incidents.

To outline the process for effectively investigating accidents and incidents.

To facilitate an effective investigation.

Accident Investigation

Important part of any safety management system. Highlights the reasons why accidents occur and how to prevent them.

The primary purpose of accident investigations is to improve health and safety performance by:

Exploring the reasons for the event and identifying both the immediate and underlying causes;

Identifying remedies to improve the health and safety management system by improving risk control, preventing a recurrence and reducing financial losses.

What to Investigate?

All accidents whether major or minor are caused.

Serious accidents have the same root causes as minor accidents as do incidents with a potential for serious loss. It is these root causes that bring about the accident, the severity is often a matter of chance.

Accident studies have shown that there is a consistently greater number of less serious accidents than serious accidents and in the same way a greater number of incidents then accidents.

Many accident ratio studies have been undertaken and the one shown below is based on studies carried out by the Health & Safety Executive.

Accident Studies

In all cases the non injury incidents had the potential to become events with more serious consequences.

Such ratios clearly demonstrate that safety effort should be aimed at all accidents including unsafe practices at the bottom of the pyramid, with a resulting improvement in upper tiers.

Peterson (1978) in defining the principles of safety management says that an unsafe act, an unsafe condition, an accident are symptoms of something wrong within the managements system.

Accident Studies

All events represent a degree of failure in control and are potential learning experiences. It therefore follows that all accidents should be investigated to some extent.

This extent should be determined by the loss potential, rather then just the immediate effect.

Stages in an Accident/Incident Investigation

The stages in an accident/incident investigation are shown in the following diagram.

Dealing with Immediate Risks

When accidents and incidents occur immediate action may be necessary to:

Make the situation safe and prevent further injury.

Help, treat and if necessary rescue injured persons.

An effective response can only be made if it has been planned for in advance.

Selecting the level of investigation

The greatest effort should be put into:

Those involving severe injuries, ill-health or loss.

Those which could have caused much greater harm or damage.

These types of accidents and incidents demand more careful investigation and management time. This can usually be achieved by:

Looking more closely at the underlying causes of significant events.

Assigning the responsibility for the investigation of more significant events to more senior managers.

Investigating the Event

The purpose of investigations is to establish:

The way things were and how they came to be.

What happened the sequence of events that led to the outcome.

Why things happened as they did analysing both the immediate and underlying causes.

What needs to be done to avoid a repetition and how this can be achieved.

A few sources should give the investigator all that is needed to know.

Interviewing the person(s) involved and witnesses to the accident is of prime importance, ideally in familiar surroundings so as not to make the person uncomfortable.

The interview style is important with emphasis on prevention rather than blame.

The person(s) should give an account of what happened in their terms rather than the investigators.

Interviews

Interviews

Interviews should be separate to stop people from influencing each other.

Questions when asked should not be intimidating as the investigator will be seen as aggressive and reflecting a blame culture.

Observation

The accident site should be inspected as soon as possible after the accident. Particular attention should/must be given to:

Positions of people.

Personnel protective equipment (PPE).

Tools and equipment, plant or substances in use.

Orderliness/Tidiness.

Documents

Documentation to be looked at includes:

Written instructions, procedures and risk assessments which should have been in operation and followed. The validity of these documents may need to be checked by interview. The main points to look for are:

Are they adequate/satisfactory? Were they followed on this occasion? Were people trained/competent to follow it?

Records of inspections, tests, examination and surveys undertaken before the event. These provide information on how and why the circumstances leading to the event arose.

Determining Causes

Collect all information and facts which surround the accident.

Immediate causes are obvious and easy to find. They are brought about by unsafe acts and conditions and are the ACTIVE FAILURES. Unsafe acts show poor safety attitudes and indicate a lack of proper training.

These unsafe acts and conditions are brought about by the so called root causes. These are the LATENT FAILURES and are brought about by failures in organisation and the managements safety system.

Determine what changes are needed

The investigation should determine what control measures were absent, inadequate or not implemented and so generate remedial action for implementation to correct this.

Generally, remedial actions should follow the hierarchy of risk control:

Eliminate Risks by substituting the dangerous by the inherently less dangerous.

Combat risks at source by engineering controls and giving collective protective measures priority.

Minimise risk by designing suitable systems of working.

Use PPE as a last resort.

Recording & Analysing the Results

Recorded in a similar and systematic manner.

Provides a historical record of the accident.

Analysis of the causes and recommended preventative protective measures should be listed.

Completed as soon after the accident as possible.

Information on the accident and remedial actions should be passed to all supervisors.

Appropriate preventative measures may also have to be implemented by such supervisors.

Investigation reports and accident statistics should be analysed from time to time to identify common causes, features and trends not be apparent from looking at events in isolation.

Reviewing the Process

Reviewing the accident/incident investigation process should consider:

The results of investigations and analysis.

The operation of the investigation system (in terms of quality and effectiveness).

Line managers should follow through and action the findings of investigations and analysis. Follow up systems should be established where necessary to keep progress under control.

The investigation system should be examined from time to time to check that it consistently delivers information in accordance with the stated objectives and standards. This usually requires:

Checking samples of investigation forms to verify the standard of investigation and the judgements made about causation and prioritisation of remedial actions.

Checking the numbers of incidents, near misses, injury and ill-health events;

Checking that all events are being reported.

What is your definition of an Accident?

What is an Accident

an unplanned event

- an unplanned incident involving injury or fatality
- a series of events culminating in an unplanned and unforeseen event

How do Accidents occur?

- Accidents (with or without injuries) occur when a series of unrelated events coincide at a certain time and space.

-This can be from a few events to a series of a dozen or more(Because the coincidence of the series of events is a matter of luck, actual accidents only happen infrequently)

Unsafe Acts

- An unsafe act occurs in approx 85%- 95% of all analyzed accidents with injuries- An unsafe act is usually the last of a series of events before the accident occurs (it could occur at any step of the event)- By stopping or eliminating the unsafe act, we can stop the accident from occurring

What is an Accident Investigation?

A systematic approach to the identification of causal factors and implementation of corrective actions without placing blame on or finding personal fault. The information collected during an investigation is essential to determine trends and taking appropriate steps to prevent future accidents.

Which Accidents should be
Recorded or Reported?

ALL accidents (including illnesses) shallbe recorded and reportedthrough the established procedures and guidance as provided by NOAA Safety Division

Why Investigate Accidents?

Determine the cause

Develop and implement corrective actions

Document the events

Meet legal requirements

Primary Focus:

PREVENT REOCCURENCE!!!PREVENT REOCCURENCE!!!PREVENT REOCCURENCE!!!

I.Background Information:

Stress the importance of investigating incidents. Your investigation team must understand that their job can save the organization a lot of money and help prevent a similar accident from occurring in the future. The input of every member of the investigation team is vital to a thorough and successful investigation report.

II.Speakers Notes:

Why should we investigate accidents? To prevent future accidents from occurring is the number one reason. Also, accident investigations will usually bring out hidden safety issues that can be addressed in other work areas to prevent accidents in those areas.

Determining the cause is not a reason to place blame. Usually there are multiple causes or contributing factors. Digging into the root or main cause may take time, because it may be hidden under a number of easy or apparent causes.

We also need to document the NMFS version of the incident for reporting to the Occupational Safety and Health Administration (OSHA) and so the workers compensation claim can be managed correctly.

Accident vs. Near-Miss

Accident :

Any undesired, unplanned event arising out of a given work-related task which results in physical injury/ illness or damage to property.

Near-Miss :

Events which did not result in injury/illness or damage but had the potential to do so.

Accident Ratio Study

30

1

10

600

6000

Serious or Disabling

Minor Injuries

Property Damage

Accidents with no visible injury or damage

Unsafe Acts or Conditions

Accident Causes

Unsafe Act

- an act by the injured person or another person (or both) which caused the accident, and/or

Unsafe Condition

- some environmental or hazardous situation which caused the accident independent of the employee

Accident Causation Model

Results of the accident

- physical harm- property damage

Incident Occurrence

- contact with- type

Immediate causes

- practices- conditions

Basic causes

- personal factors- job factors- supervisory performance- management policy and decisions

Results of the Accident

Physical Harm

- catastrophic (multiple deaths)- single death- disabling- serious- minor

Property Damage

- catastrophic- major- serious- minor

Incident Occurrence

Type

- struck by- struck against- slip, trip - fell from- caught on- fell on same level- caught in- overexertion

Contact with

- electricity- equipment- noise- vibration- hazmat- heat/cold- radiation- animals/insects

Immediate Causes

Practices

- operating without authority- use equipment improperly- not using PPE when required- correct lifting procedures not established- drinking or drug use- horseplay- equipment not properly secured

Immediate Causes (contd)

Conditions

- ineffective guards- unserviceable tools and equipment- inadequate warning systems- bad housekeeping practices- poor work space illumination- unhealthy work environment

Basic Causes

Personal Factors

- lack of knowledge or skill- improper motivation- physical or mental condition- literacy or ability

Job Factors

- Physical environment- sub-standard equipment- abnormal usage- wear and tear- inadequate standards- design and maintenance

Basic Causes (contd)

Supervisory Performance

- inadequate instructions- failure of SOPs- rules not enforced- hazards not corrected- devices not provided

Management Policy and Decisions

- set measurable standards- measure work in progress- evaluate work vs. standards- correct performance

No animals were hurt as a result of this accident

Severity of Incident
(NOAA Safety Policy NAO-209-1)

Major

- Employee fatality, - Hospitalization of 3 or more employees, - Permanent employee disability, - Five or more lost workdays, - Conditions that could pose an imminent and threat of serious injury/illness to other employees - Property losses in excess of $1 Million

Minor

- All other (less serious) incidents and unsafe conditions reported by employees

Who Investigates?

Major Accidents

- NOAA GO TEAM Investigation Team - LO Representative - Other agencies such as NTSB, USCG, OSHA

Minor Accidents

- First-Line Supervisor - Site Director or Manager - Site Safety Representative - NOAA SECO (if needed)


Your accident investigation and reporting procedures should explain who is responsible for investigating the different types of accidents.

This is just an example of which employees might be on the investigation team. Please make the appropriate changes so the information coincides with your companys accident investigation and reporting procedures.

How NOAAs accident investigation and reporting procedures define minor and major accidents? Make sure the definitions in the Speakers Notes: match the description in your companys plan.

II.Speakers Notes:

A minor accident is one in which no injury occurs or the most severe injury only requires first-aid, not a visit to the doctor. This type of accident or near miss can easily be handled by the injured employees supervisor and a member of the safety committee. The chosen safety committee member should work in a different department so he or she can look at the situation from a fresh perspective.

A major accident is one in which the injury is severe enough that a doctors visit is required. Again the supervisor will be involved, along with at least one member (possibly more) of the safety committee. The safety manager and production manager will also be involved.

The assembled investigation team decides who leads the investigation and who will be responsible for writing the report.

Investigators Qualifications

Technical knowledge

Objectivity

Analytical approach

Familiarity with the job, process or operation

Tact in communicating

Intellectual honesty

Inquisitiveness and curiosity


The employees in this class will have the basis to become qualified trainers just
by their participation in this class. Once they understand the importance of the investigation and learn how to find and communicate details, they will be effective members of an investigation team.

II.Speakers Notes:

Not everyone is permitted to investigate accidents. Obviously, you are on your
way due to your participation in this class. By the end of this session you will understand the proper way to investigate accidents.

You should also understand the importance of conducting an investigation. If you dont take the investigation process seriously, or just go through the motions, the investigation will not be valid.

A thorough investigation requires the ability to seek out hidden details and to communicate those details successfully so that others reading the investigation report will be able to picture exactly what happened.

When to Investigate?

Immediately after incident

Witness memories fade

Equipment and clues
are moved

Finish investigation quickly


How do you notify or assemble the investigation team? Is the SECO or safety focal point contacted, and then they contact members of the investigation team?

II.Speakers Notes:

Ideally, the investigation should begin immediately. The investigation team should be assembled and the process should begin even while the injured employee is still being treated.

The memories of the injured employee and witnesses are affected by time. They may elaborate on the story or forget important details if they are not questioned immediately.

Potential causal factors might be removed. For example, the equipment involved may be moved, the slippery floor cleaned up, the broken ladder repaired. Investigators want to arrive at the scene before anything is changed.

If the investigation team cannot arrive at the scene immediately, they should make
it a priority to arrive as soon as possible.

Waiting a day or two is just not acceptable. By then you have lost important information, and the investigation will not be complete. Recommendations from the investigation may not be valid because they are based on inaccurate information.

What to Investigate?

All accidents and near-misses

- Conduct investigation upon first notification - Keeping the scene in-tact and recording witnesses statements early is key to a successful investigation

Accident Investigation Kit

May Include:

Digital Camera

Report forms, clipboard, pens

Barricade tape

Flashlight

Tape measure

Tape recorder

Personal Protective Equipment (as appropriate)


Do you have an accident investigation kit made up? If so, where is it located? Who has access to the kit? Who is responsible for obtaining the kit when the investigation team is called? All of this information should be explained in your accident investigation and reporting procedures.

II.Speakers Notes:

This slide lists the essential elements of an investigation kit.

Pictures can be taken and used as evidence or to help supplement the report.

Having the report forms will help make sure details are not overlooked while conducting the investigation.

Barricade tape is used to block off the accident scene until the investigation is complete.

A flashlight may be needed to look for those hidden details

A tape measure records the height of fall, etc.

A tape recorder can be used by all team members to record witnesses statements
or investigators observations.

Work gloves are needed because equipment or debris may need to be moved.

The Accident Occurs

Employee or co-worker immediately reports the accident to a supervisor

Supervisor secures/assesses the scene to prevent additional injuries to other employees, before assisting the injured employee

Supervisor treats the injury or seeks medical treatment for the injured

The accident scene is left intact

Site safety rep is contacted to assist the supervisor in the investigation of the accident.


Your employees should already understand the importance of immediately reporting all incidents, including near misses. This is stressed in the New Employee Safety Orientation training session.

Do your supervisors understand how to handle an injured employee? Have they been trained in first-aid/CPR? Do they take the injured worker to the doctor if necessary?

Does the supervisor know how to initiate an incident investigation? Do they understand the importance of leaving the incident scene intact for the investigators?

Make sure the supervisor understands that the employee should complete the employee account of incident form as soon as possible.

II.Speakers Notes:

Employees are responsible for immediately reporting all injuries, near miss incidents, and facility-damaging accidents.

Remember, as a supervisor, you are responsible for ensuring all injured personnel receive proper treatment.

Do not touch the incident scene until the investigation team arrives, unless something presents an immediate danger to other personnel, until the investigation team arrives.

Contact the incident investigation team and have the injured employee complete the employee account of the incident form.

Beginning the Investigation

Gather investigation
members and kit

Report to the scene

Look at the big
picture

Record initial
observations

Take pictures


How does NMFS call for an investigation team to gather? Who determines the members of a particular investigation team?

Who retrieves the investigation kit?

Pass out Accident Investigation forms.

II.Speakers Notes:

Once the team has gathered at the scene, decide who will be the team leader.

Step back from the scene to look at the big picture. Do you observe anything that
is unusual or out of place?

Record your initial observations. Try not to record what you think may have happened; just record what you see.

Take pictures or a video.

Whats Involved?

Who was injured?

Medication, drugs,
or alcohol?

Was employee ill or

fatigued?

Environmental conditions?


Does NMFS have any kind of post-accident drug screen requirement?
If so, you will find out later if the injured employee was on alcohol or illegal drugs.

Most of the information contained in this slide will have to be taken from the employees statement. The employee may not think to include all of this information, so make sure the employee is thoroughly interviewed.

II.Speakers Notes:

Write down the complete name of the injured employee(s). What department
do they work in? Who is the supervisor?

Have the injured employee complete his or her account of the incident.

Was the injured employee taking any medication, either prescription or non-prescription, such as pain medicine, allergy medicine, aspirin, etc.? Is the employee diabetic or subject to seizures? Is there any evidence of use of alcohol or illegal drugs?

Was the employee feeling ill lately (if so, the employee may have been taking medication)? Did the employee have symptoms of drowsiness, upset stomach, headaches, etc.?

Was the injured employee working a double shift or rotating shifts? Fatigue or the adjustment in work hours may have contributed to the incident.

When interviewing the injured employee, do not come across as trying to find the employee at fault for the accident. Just tell the employee that these are standard questions on the form that have to be answered.

Witnesses

Who witnessed the

accident?

Was a supervisor or

Team Lead nearby?

Where were other

employees?

Why didnt anyone

witness the accident (working alone, remote areas)?

I.Speakers Notes:

Write down the name(s) of the witness(es), the departments in which they work, and the names of their supervisors.

Interview witnesses separately and write down or record their statements. Some questions to ask witnesses include:Were there any unsafe acts on the part of the person involved that precipitated the incident (i.e., horseplay or not following proper safety procedures).

Do you know of any personal factor on the part of the individual involved that may have induced an unsafe condition (i.e., inexperience, alcohol use or fatigue).

If supervisors were nearby, was the employee being directly supervised? Where was the supervisor at the time of the accident?

Use a facility map or draw a picture of where other employees, including witnesses, were located when the accident occurred. What were they doing?

If there were no witnesses, why not? Was the injured employee working alone? If not, why had the other employees left the injured employee alone? Was the fact that the employee was alone a contributing factor?

Interviewing Tips

Discuss what happened leading
up to and after the accident

Encourage witnesses to describe
the accident in their own words

Dont be defensive or judgmental

Use open-ended questions

Do not interrupt the witness


If time allows, have the employees conduct some mock interviews to get them comfortable with the process.

II.Speakers Notes:

When interviewing, avoid using domineering or patronizing mannerisms or speech. The interviewee will probably not respond well to this attitude.

Convey your sincere concern for the safety of employees at your facility and let them know that you are trying to find ways to fix the cause of this accident.

Do not interrupt the interviewee; take detailed notes.

Review your notes at the end of the interview to avoid any misunderstanding.

What was Involved?

Machine, tool, or equipment

Chemicals

Environmental conditions

Field season prep operations

I.Speakers Notes:

Was the injured employee operating a machine, tool, or piece of equipment that may have contributed to the incident? Was there a malfunction? Was the employee trained to use the equipment? How much experience did the employee have with the equipment? Was the employee being directly supervised while using the equipment? Was the employee wearing proper PPE, if required?

Was the employee using a chemical at the time of the incident? If so, was the employee properly trained, experienced, or supervised? Was the employee wearing appropriate PPE?

Environmental factors include: slippery floor, inadequate lighting, crowded work space, noise, stress, etc.

The work schedule can be a factor if the work level was increased well above normal levels. Did this increase cause the injured employee to bypass safety procedures in order to speed up production? Were safety hazards ignored because production had to be finished?

Date and time?

Normal shift or

working hours?

Employee coming
off a vacation?

Time of Accident

I.Speakers Notes:

Note the date and exact time of the incident. Was this just before or after a break?
Did the injury occur early Monday morning, when the employee may have been tired from a busy weekend?

Was the employee working his or her normal shift and performing a normal job function? If not, why was the employee doing work that was outside of the normal work functions?

Was the employee coming off of a vacation or sick leave? Is it possible that the employee was daydreaming about the vacation he or she planned to start the next day?

Accident Location

Work area

On, under, in, near

Off-site address

Doing normal job duties

Performing non-routine or routine tasks (i.e., properly trained)

I.Speakers Notes:

The incident location needs to be specific. Start with the main work area such as: the northwest corner of the maintenance shop, lobby of the main office, main deck of the vessel.

Now get specific:Was the employee on something such as a ladder, a machine, a platform,
a chair, a staircase, etc.?

Was the injured employee under a overhead load, workbench, a machine, etc.?

Was the employee in a forklift, manlift, confined space, etc.?

If the accident occurred off-site, make sure the address of the accident site
is noted along with these details.

Was the injured employee doing work that is part of his or her normal job functions? If not, was the employee properly trained to do the work?

Employees Activity

Motion conducted at time of accident

Repetitive motion?

Type of material being handled

I.Speakers Notes:

What type of motion was the injured employee conducting at the time of the accident? Examples include: walking, running, bending over, squatting, climbing, operating a lever, pushing a broom, using a scalpel, turning a valve, turning a wrench, pounding
a hammer, etc.

Were the motions repetitive?

Were they handling heavy or light material? Was it big and bulky? Did they have help, or were they using appropriate material handling equipment, such as a pallet jack or truck dollies?

Accident Narrative

Describe the details so the reader
can clearly picture the accident

Specific body parts affected

Specific motions

of injured employee just before, during, and after accident


Detailed description is important for claims management. Should the employee later claim that he also injured his knee in the accident, you have a detailed account in which no one witnessed his holding a knee or limping after the accident to indicate that the knee was also injured.

II.Speakers Notes:

The incident should be described on the report in such detail that any reader can clearly picture what happened. For example: The injured employee was walking east down the main aisle, staying to the north side of the aisle, in building #4. He was carrying two boxes of samples with a combined weight of 35 pounds; however, the boxes did come up to his chin and limited his field of vision. The employee did not see the 6-foot, 1/2-inch-diameter extension cord that was laying on the floor and protruding 18 inches into the aisle right next to the newly installed U-Make-It machine. The injured employee stepped on the cord with his left foot, which then rolled forward.

Body parts: The employee fell onto his left side and did not have time to break his fall, so his left elbow squarely struck the ground. The boxes were released
upon impact. Three of the sample containers broke, spilling approximately 1.5 liters of 10% formalin.

Motions after the incident. The employee rolled to his back, sat up and held his
left elbow in his right hand. He sat in this position for about a minute before being helped to his feet.

Causal Factors

Try not to accept single cause theory

Identify underlying causes (root)

Primary cause

Secondary causes

Contributing causes

Effects

I.Speakers Notes:

There are almost always multiple causes that contribute to an accident. Try not
to settle on a single cause theory, because there are usually contributing factors.

What are all the possible underlying causes or contributing factors. In the example described on the last slide: The employee was carrying a load that partially blocked his vision, the cord should not have protruded out to the aisle. Other considerations: Was the aisle properly lighted? Was there a noise or something that distracted the injured worker from looking down, etc.?

Once the list of potential causes or contributing factors has been compiled, try to determine the primary cause, or the cause that appears to have contributed the most to the accident. This is the cause that, if removed, the accident probably would have been prevented.

Other causes will be considered as secondary potential causes.

All causes should be investigated for corrective actions; however, the primary cause should be the focus of corrective actions.

Corrective Actions Taken

Include immediate interim controls implemented at the time of accident

Recommended corrective actions

Employee training

Preventive maintenance activities

Better operating procedures

Hazard recognition (ORM)

Management awareness of risks involved


Does NMFS accident investigation and reporting procedures have a form for documenting and recommending corrective actions to management?

II.Speakers Notes:

Immediate corrective actions are those that are done right after the investigation is complete. These will remove a danger and prevent a repeat of the accident until formal, or long-term, corrective actions can be completed. These do not need a recommendation form, because they are implemented immediately by the supervisor or the investigation team. For example, put the extension cord back in its proper storage location before someone else slips on it.

Once the investigation team has compiled the investigation report, they can make a number of recommendations to management. Recommendations might include retraining employees on lifting and carrying techniques and material handling equipment, retraining maintenance on putting material away when the job is finished, or maybe improving the lighting in that area of the facility.

Immediate Notification

Supervisor shall complete the NOAA Web Based Accident/ Illness Report Form and submit within 24 hours of incident occurrence (8 hours for major incidents).

Accident Analysis Summary

Investigate accident immediately

Determine who was involved and
who witnessed it

Ascertain what items or equipment
were involved

Record detailed description

Determine causal factors

Implement corrective actions

I. Speakers Notes:

To summarize, these are the steps you should follow when an accident occurs.

Questions ??

Quiz

What is an Accident Investigation?

A systematic approach to the identification of causal factors and implementation of corrective actions.

Finding personal fault and placing blame.

The appropriate steps to prevent future actions.

The essential step to determine trends and taking action against person or persons at fault.

Which Accidents should be Recorded or Reported?

Only on the job accidents.

ALL accidents (including illnesses) shall be recorded and reported.

Only on the job accidents on illnesses that occur on the job and reported within 8 hours.

All accidents shall be recorded and reported.

Why Investigate Accidents?

To develop and implement corrective actions.

To document the events.

The Primary Focus is to PREVENT REOCCURENCE!!!

To determine the cause.

Accident vs. Near-Miss?

Any unplanned event arising out of work that resulted in injury vs. Any event which did not result in injury but had potential to do so.

Any unsafe work habit vs. Any Hazardous working conditions.

Any event which warns us of a problem vs. Any circumstances that result in injury or property damage.

Which of the following are the basic areas that are looked at in an Accident Investigation.

Policies.

Equipment.

Training.

All of the above.


Accident analysis is carried out in order to determine the cause or causes of an accident or series of accidents so as to prevent further incidents of a similar kind. It is also known as accident investigation.


It may be performed by a range of experts, including forensic scientists, forensic engineers or health and safety advisers. Accident investigators, particularly those in the aircraft industry, are colloquially known as "tin-kickers".

Sequence

Accident analysis is performed in four steps:

Fact gathering: After an accident happened a forensic process starts to gather all possibly relevant facts that may contribute to understanding the accident.

Sequence
Fact Analysis:

After the forensic process has been completed or at least delivered some results, the facts are put together to give a "big picture." The history of the accident is reconstructed and checked for consistency and plausibility.

Sequence
Conclusion Drawing:

If the accident history is sufficiently informative, conclusions can be drawn about causation and contributing factors.

Sequence
Counter-measures:

In some cases the development of counter-measures is desired or recommendations have to be issued to prevent further accidents of the same kind.

Methods

There exist numerous forms of Accident Analysis methods. These can be divided into three categories:

Methods
Causal Analysis

Causal Analysis uses the principle of causality to determine the course of events. Though people casually speak of a "chain of events", results from Causal Analysis usually have the form of directed a-cyclic graphs-the nodes being events and the edges the cause-effect relations. Methods of Causal Analysis differ in their respective notion of causation.

Methods
Expert Analysis

Expert Analysis relies on the knowledge and experience of field experts. This form of analysis usually lacks a rigorous (formal/semiformal) methodological approach. This usually affects falsify-ability and objectivity of analyses. This is of importance when conclusions are heavily disputed among experts.

Methods
Organizational Analysis

Organizational Analysis relies on systemic theories of organization. Most theories imply that if a system's behaviour stayed within the bounds of the ideal organization then no accidents can occur.

Methods
Organizational Analysis

Organizational Analysis can be falsified and results from analyses can be checked for objectivity. Choosing an organizational theory for accident analysis comes from the assumption that the system to be analysed conforms to that theory.

Using Digital Photographs to Extract Evidence

Once all available data has been collected by accident scene investigators and law enforcement officers, camera matching, photogrammetry or rectification can be used to determine the exact location of physical evidence shown in the accident scene photos.

Camera matching:

Camera matching uses accident scene photos that show various points of evidence. The technique uses CAD software to create a 3-dimensional model of the accident site and roadway surface.

Camera matching:

All survey data and photos are then imported into a three dimensional software package like 3D Studio Max. A virtual camera can be then be positioned relative to the 3D roadway surface. Physical evidence is then mapped from the photos onto the 3D roadway to create a three dimensional accident scene drawing.

Photogrammetry

Photogrammetry is used to determine the three-dimensional geometry of an object on the accident scene from the original two dimensional photos.

Photogrammetry

The photographs can be used to extract evidence that may be lost after the accident is cleared. Photographs from several viewpoints are imported into software like PhotoModeler.

Photogrammetry

The forensic engineer can then choose points common to each photo. The software will calculate the location of each point in a three dimensional coordinate system.

Rectification

Photographic rectification is also used to analyze evidence that may not have been measured at the accident scene. Two dimensional rectification transforms a single photograph into a top-down view. Software like PC-Rect can be used to rectify a digital photograph.

Failure mode and effects analysis


Failure Mode and Effects Analysis (FMEA) was one of the first systematic techniques for failure analysis.

It was developed by reliability engineers in the 1950s to study problems that might arise from malfunctions of military systems.


A FMEA is often the first step of a system reliability study. It involves reviewing as many components, assemblies, and subsystems as possible to identify failure modes, and their causes and effects.


For each component, the failure modes and their resulting effects on the rest of the system are recorded in a specific FMEA worksheet. There are numerous variations of such worksheets. A FMEA is mainly a qualitative analysis.


A few different types of FMEA analysis exist, like

Functional, Design, and Process FMEA.


Sometimes the FMEA is called FMECA to indicate that Criticality analysis is performed also.


An FMEA is an inductive reasoning (forward logic) single point of failure analysis and is a core task in reliability engineering, safety engineering and quality engineering. Quality engineering is specially concerned with the "Process" (Manufacturing and Assembly) type of FMEA.


A successful FMEA activity helps to identify potential failure modes based on experience with similar products and processes - or based on common physics of failure logic.


It is widely used in development and manufacturing industries in various phases of the product life cycle. Effects analysis refers to studying the consequences of those failures on different system levels.


Functional analyses are needed as an input to determine correct failure modes, at all system levels, both for functional FMEA or Piece-Part (hardware) FMEA.


A FMEA is used to structure Mitigation for Risk reduction based on either failure (mode) effect severity reduction or based on lowering the probability of failure or both.


The FMEA is in principle a full inductive (forward logic) analysis, however the failure probability can only be estimated or reduced by understanding the failure mechanism.


Ideally this probability shall be lowered to "impossible to occur" by eliminating the (root) causes. It is therefore important to include in the FMEA an appropriate depth of information on the causes of failure (deductive analysis).


The FME(C)A is a design tool used to systematically analyze postulated component failures and identify the resultant effects on system operations. The analysis is sometimes characterized as consisting of two sub-analyses, the first being the failure modes and effects analysis (FMEA), and the second, the criticality analysis (CA).


Successful development of an FMEA requires that the analyst include all significant failure modes for each contributing element or part in the system. FMEAs can be performed at the system, subsystem, assembly, subassembly or part level.


The FMECA should be a living document during development of a hardware design. It should be scheduled and completed concurrently with the design. If completed in a timely manner, the FMECA can help guide design decisions. The usefulness of the FMECA as a design tool and in the decision making process is dependent on the effectiveness and timeliness with which design problems are identified.


Timeliness is probably the most important consideration. In the extreme case, the FMECA would be of little value to the design decision process if the analysis is performed after the hardware is built.


While the FMECA identifies all part failure modes, its primary benefit is the early identification of all critical and catastrophic subsystem or system failure modes so they can be eliminated or minimized through design modification at the earliest point in the development effort.


Therefore, the FMECA should be performed at the system level as soon as preliminary design information is available and extended to the lower levels as the detail design progresses.


Remark: For more complete scenario modelling other type of Reliability analysis may be considered, for example fault tree analysis(FTA); a deductive (backward logic) failure analysis that may handle multiple failures within the item and/or external to the item including maintenance and logistics. It starts at higher functional / system level. A FTA may use the basic failure mode FMEA records or an effect summary as one of its inputs (the basic events). Interface hazard analysis, Human error analysis and others may be added for completion in scenario modelling.

Functional analysis

The analysis may be performed at the functional level until the design has matured sufficiently to identify specific hardware that will perform the functions; then the analysis should be extended to the hardware level. When performing the hardware level FMECA, interfacing hardware is considered to be operating within specification. In addition, each part failure postulated is considered to be the only failure in the system (i.e., it is a single failure analysis).

Functional analysis

In addition to the FMEAs done on systems to evaluate the impact lower level failures have on system operation, several other FMEAs are done. Special attention is paid to interfaces between systems and in fact at all functional interfaces. The purpose of these FMEAs is to assure that irreversible physical and/or functional damage is not propagated across the interface as a result of failures in one of the interfacing units.

Functional analysis

These analyses are done to the piece part level for the circuits that directly interface with the other units. The FMEA can be accomplished without a CA, but a CA requires that the FMEA has previously identified system level critical failures. When both steps are done, the total process is called a FMECA.

Ground rules

The ground rules of each FMEA include a set of project selected procedures; the assumptions on which the analysis is based; the hardware that has been included and excluded from the analysis and the rationale for the exclusions. The ground rules also describe the indenture level of the analysis, the basic hardware status, and the criteria for system and mission success.

Ground rules

Every effort should be made to define all ground rules before the FMEA begins; however, the ground rules may be expanded and clarified as the analysis proceeds. A typical set of ground rules (assumptions) follows:

Ground rules

Only one failure mode exists at a time.

All inputs (including software commands) to the item being analyzed are present and at nominal values.

All consumables are present in sufficient quantities.

Nominal power is available

Benefits

Major benefits derived from a properly implemented FMECA effort are as follows:

Benefits

It provides a documented method for selecting a design with a high probability of successful operation and safety.

Benefits

A documented uniform method of assessing potential failure mechanisms, failure modes and their impact on system operation, resulting in a list of failure modes ranked according to the seriousness of their system impact and likelihood of occurrence.

Benefits

Early identification of single failure points (SFPS) and system interface problems, which may be critical to mission success and/or safety. They also provide a method of verifying that switching between redundant elements is not jeopardized by postulated single failures.

Benefits

An effective method for evaluating the effect of proposed changes to the design and/or operational procedures on mission success and safety.

Benefits

A basis for in-flight troubleshooting procedures and for locating performance monitoring and fault-detection devices.

Benefits

Criteria for early planning of tests.

Basic terms

The following covers some basic FMEA terminology.

Failure The loss under stated conditions.

Basic terms
Failure mode

The specific manner or way by which a failure occurs in terms of failure of the item (being a part or (sub) system) function under investigation; it may generally describe the way the failure occurs. It shall at least clearly describe a (end) failure state of the item (or function in case of a Functional FMEA) under consideration. It is the result of the failure mechanism (cause of the failure mode). For example; a fully fractured axle, a deformed axle or a fully open or fully closed electrical contact are each a separate failure mode.

Basic terms
Failure cause and/or mechanism

Defects in requirements, design, process, quality control, handling or part application, which are the underlying cause or sequence of causes that initiate a process (mechanism) that leads to a failure mode over a certain time. A failure mode may have more causes.

Basic terms
Failure cause and/or mechanism

For example; "fatigue or corrosion of a structural beam" or "fretting corrosion in a electrical contact" is a failure mechanism and in itself (likely) not a failure mode. The related failure mode (end state) is a "full fracture of structural beam" or "an open electrical contact". The initial Cause might have been "Improper application of corrosion protection layer (paint)" and /or "(abnormal) vibration input from another (possible failed) system".

Basic terms / Failure effect

Immediate consequences of a failure on operation, function or functionality, or status of some item.

Indenture levels (bill of material or functional breakdown)

An identifier for system level and thereby item complexity. Complexity increases as levels are closer to one.

Local effect

The failure effect as it applies to the item under analysis.

Next higher level effect

The failure effect as it applies at the next higher indenture level.

End effect

The failure effect at the highest indenture level or total system.

Detection

The means of detection of the failure mode by maintainer, operator or built in detection system, including estimated dormancy period (if applicable)

Risk Priority Number (RPN)

Cost (of the event) * Probability (of the event occurring) * Detection (Probability that the event would not be detected before the user was aware of it)

Severity

The consequences of a failure mode. Severity considers the worst potential consequence of a failure, determined by the degree of injury, property damage, system damage and/or time lost to repair the failure.

Remarks / mitigation / actions

Additional info, including the proposed mitigation or actions used to lower a risk or justify a risk level or scenario.

Example FMEA Worksheet

Probability (P)

In this step it is necessary to look at the cause of a failure mode and the likelihood of occurrence. This can be done by analysis, calculations / FEM, looking at similar items or processes and the failure modes that have been documented for them in the past. A failure cause is looked upon as a design weakness. All the potential causes for a failure mode should be identified and documented.

Probability (P)

This should be in technical terms. Examples of causes are: Human errors in handling, Manufacturing induced faults, Fatigue, Creep, Abrasive wear, erroneous algorithms, excessive voltage or improper operating conditions or use (depending on the used ground rules). A failure mode is given an Probability Ranking.

Probability (P)

Severity (S)

Determine the Severity for the worst case scenario adverse end effect (state). It is convenient to write these effects down in terms of what the user might see or experience in terms of functional failures. Examples of these end effects are: full loss of function x, degraded performance, functions in reversed mode, too late functioning, erratic functioning, etc.

Severity (S)

Each end effect is given a Severity number (S) from, say, I (no effect) to VI (catastrophic), based on cost and/or loss of life or quality of life. These numbers prioritize the failure modes (together with probability and detectability). Below a typical classification is given. Other classifications are possible. See also hazard analysis.

Severity (S)

Detection (D)

Detection (D)

The means or method by which a failure is detected, isolated by operator and/or maintainer and the time it may take. This is important for maintainability control (Availability of the system) and it is specially important for multiple failure scenarios.

Detection (D)

This may involve dormant failure modes (e.g. No direct system effect, while a redundant system / item automatic takes over or when the failure only is problematic during specific mission or system states) or latent failures (e.g. deterioration failure mechanisms, like a metal growing crack, but not a critical length).

Detection (D)

It should be made clear how the failure mode or cause can be discovered by an operator under normal system operation or if it can be discovered by the maintenance crew by some diagnostic action or automatic built in system test. A dormancy and/or latency period may be entered.

Detection (D)

Detection (D)

DORMANCY or LATENCY PERIOD The average time that a failure mode may be undetected may be entered if known. For example:

During aircraft C Block inspection, preventive or predictive maintenance, X months or X flight hours During aircraft B Block inspection, preventive or predictive maintenance, X months or X flight hours During Turn-Around Inspection before or after flight (e.g. 8 hours average) During in-built system functional test, X minutes Continuously monitored, X seconds

Education

Accident Investigation and Analysis