RISK ANALYSIS OF ELECTROMAGNETIC

ENVIRONMENTAL EFFECTS IN AIRCRAFT

SYSTEMGUIDE:MISS JISHA.M.V PRESENTED BY,

ASSISTANT PROFFESSOR KAVYA.P.P.

ECE DEPARTMENT ROLL NO:39

o The interaction of electrical and magnectic fields emanating from systems

within an aircraft,or the interaction between the aircraft and the external

environment,can create unwanted effects,which may adversely impact the

flight of aircraft.

o Electromagnectic Environmental Effects(E3) in aircraft is one of the major

concerns to aviation industry.

o Protection of aircraft designs against Electromagnectic Environmental

Effect(E3) therfore must be assured as part of initial design.

2EC DEPARTMENT

o Hazardous electromagnetic Environmental Effect in aircraft

systems includes

• Lightning

• High Intensity Radiated Fields(HIRF)

• Precipitation-static(P-static)

• Portable electronic devices(PEDs)

• Electromagnetic compatibility(EMC)

3EC DEPARTMENT

• Lightning:

The electromagnetic interference caused by lightning striking the aircraft is

the major issue.

The high energy and high voltage can effect the aircraft hardware as well

as the data.

• HIRF: High Intensity Radiated Field

Electromagnetic interference caused by HIRF have adverse effect on

aircraft system.

This is an external energy source having sufficient energy.

• EMC:Electromagnectic Compatibility

EMC means that a device is compatible with environment and it does not

emit levels of EM energy.

• EMI: An electromagnetic disturbance which may degrade the performance

of an equipment or causes malfunction of the equipment called

electromagnectic interfernce4EC DEPARTMENT

• PED:Portable Electronic Device

It can produce signals that effect electronic equipment.Symptoms and

failure went off when passengers were asked to switch PED

• P-STATIC: Precipitation-static

It is an electrical charge on an airplane caused by flying through rain,

snow, ice or dust partiicles.When the aircraft charge is great enough

it discharge in to the surrounding air.

5EC DEPARTMENT

STANDARD RISK MODEL FOR E3

Risk analysis methodology is an underutilized but well suited tool for

understanding and mitigation of electromagnetic hazardous effects in

aircraft system.

• Risk is defined as the potential that something will go wrong as a result of

an event or series of events.

• One of the most helpful method to understand risk and to develop

mitigation of risk.

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COMPONENTS

1 Risk event: The happening or state that triggers a loss in safety or

economic value.

2 Risk event driver:Something existing in the event environmental that

leads one to believe that a particular risk event such as EM incidents

could occur.

3 Impact of a risk: The consequence or potential loss that might result if

a risk event occurs. Impact itself may have system-subsystem-

component structure.

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4) Impact driver: Something existing in the problem situation

that leads one to believe that a particular impact such as system level EM

damage or upset could occur.

5) Total loss: The magnitude of the actual loss value acquired when a risk

event occurs

6) Probability values: Probability values are assigned to EM risk events and

impact.

9EC DEPARTMENT

ADVANTAGES OF SRM MODEL

1. The SRM is fairly simple to understand and captures the essence of

resolving risks.

2. It clearly separates the risk events and their impact thus supporting cause

and effect analysis

3. Separating risk and impact reinforces the notion of prevention or

contingency planning for risk

4. By allocating the drivers related to a risk event, we can identify the

threats and deal with those that contribute the most the risk events

10EC DEPARTMENT

E3 RISK EVENTS, IMPACTS AND DRIVERS

Risk Event Identification in Aircraft

• Direct lightning

• CAUSES:-

1. Fuel tank explosion

2. Flame damage

3. Fasteners and engine damage

4. Antenna damage

• Indirect lightning

Occurs when the lightning current on the aircraft surface generates

magnetic fields which induce voltage on the wire bundles

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HIRF EVENTS

• Couple the energy from airport radars and radio transmitters there by

causing the damage.

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PED

• RF emission of PED’S lead to coupling with EM waves of aircraft there by

causing damage.

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P-STATIC RISK EVENT

• Which effect the radio communication and navigation of aircraft.

• Equipment to equipment interference events occurs when emitted EM

emission energy is coupled to another equipment via wires or antennas.

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FACTORS LEADING TO RISK EVENTS

• Flammable vapor in fuel tank

• Triggering sparks

• Improper grounding

• Corrosion of wire bundles

• High impedance on connectors

• High susceptibility of equipment

• High level emission of PED’S

• Inadequate isolation between antenna

• Inadequate separation distance between power wires and sensor wires

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IMPACTS

Impact occurs at system level as well as component level

MAJOR IMPACTS

• Fuel tank ignition

• Damage flight control surfaces

• Disabling of flight control system

• Malfunction or permanent damage of sensor

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RISK RESOLUTION

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Risk resolution steps by creating and examining risk table and risk map

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Risk levels are first evaluated and expressed as expected loss.

Risk levels of each risk events are examined risk threshold.

Risk threshold is unique quantity for each project determined by the stakeholders.

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Risk Evaluation And Monitoring Based on Risk Map

• Risk status of each risk event is clearly understood with respect to a

threshold curve specific to an aircraft.

• Risk levels of the risk events that are located below the threshold curve

and not to address the risk event but simply monitors the risk level

• Pe and Pi should decreases and thus Le also reduces20EC DEPARTMENT

RISK EVENT PREVENTION PLAN

• Risk prevention comes out naturally by examining the risk event drivers

carefully.

• Inflammable fuel tank by using equipment such as Nitrogen generating

system(NGS).

• Providing cooling mechanism to prevent sparks, explosion etc.

• Corrosion resistant wire bundles.

• Redesigning of aircraft windows and alignment.

• Maintaining adequate separation distance between equipment.

21EC DEPARTMENT

IMPACT CONTINGENCY PLAN

• The concept of redundancy ,error correction coding and software design are

utilized to establish the impact contingency plan.

• Risk event prevention and impact contingency plan emerge in a systematic

manner by examining the risk event drivers and impact drivers.

EC DEPARTMENT 22

• Major risk events and impacts for aircraft EM hazards were identified and

their drivers have been discussed.

• Prevention,plan,monitoring methodology for aircraft EM hazards have

been developed.

Future work includes extending the approach to EM design details

in aircraft

EC DEPARTMENT 23

REFERENCE

1. C.R Paul, Introduction to electromagnetic compatibility

2. B.S Blanchard and W.J Fabryeky.system engineering and analysis fifth

edition.

3. Smith and G. M. Merritt. Protective Risk Management

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