Assessment is nothing but process of documenting.

Validation can be defined as certifying by regulations.

Hardware assessment and validation are major parts of building a modern digital avionics systems.

The proposed system can be developed by many stages of design and build

The latest phases of hardware assessment and validation are mainly focus on qualitative evaluation

It mainly depends on FTA(fault tree analysis)&FMEA(failure modes of effective analysis)

For compiling systems the fault tolerance systems are required for the use of modern computer based tools

Why because we can use finite number of states of fault tolerant systems .

Major -factors of Avionics System• Capability• Reliability• Maintainability• Certificability• Survivability(military)• Life cycle cost(military) • Technical risk• Weight & power

• Capability:

– How capable is avionics system?

– can they do the job and even more?

– Designer to maximize the capability of the systemwithin the equipment that are imposed.

• Reliability:

– Designer efforts to make systems as reliable as possible.

– High reliability less maintenance costs.

– If less reliable customer will not buy it and in terms ofcivil airlines the certificating agencies will not certify it.

• Maintainability:

–Closely related to reliability

–System must need preventive or correctivemaintenance.

–System can be maintained through builtin testing, automated troubleshooting andeasy access to hardware.

Certificability:

Major area of related for avionics in civil airlines.

Certification conducted by the regulatory agencies based on detailed, expert examination of all features of aircraft design and operation.

The avionics architecture should be straight forward and easily understandable.

Avionics certification focus on three analyses: preliminary hazard, fault tree, and FMEA.

• Survivability:– It is a function of susceptibility and vulnerability.

– Susceptibility: measure of probability that an aircraftwill be hit by a given threat.

– Vulnerability: measure of the probability that damagewill occur if there is a hit by the threat

• Life cycle cost(LCC):• It deals with economic measures need for evaluating

avionics architecture.

• It includes costs of varied items as spares acquisition,transportation, storage and training (crew andMaintenance personnel's),hardware development andtest, depreciation and interest.

• Risk:

– Amount of failures and drawbacks in the design andimplementation.

– Over come by using the latest technology and fail prooftechnique to overcome both developmental and longterm technological risks.

• Weight and power:

– Minimize the weight and power requirements are twofundamental concepts of avionics design.

– So the design must be light weight and powerconsuming which is possible through the data bus andlatest advancement of electronics devices.

Certification is most important part for civil avionics designers.

Certification is the challenging process between the designers and regulated authorities.

FAR(federal aviation regulations) establish the requirements & procedure for safety in civil transports.

For digital avionics systems ,

the most important regulation is FAR part 25.1309

FAR part 25.1309 is for equipment,system&installation

They are also other factors

FAR part 25.581 for lightning protection

FAR part 25.671 for controlsystem & general

FAR part 25.672 for stability & automatic systems

In this section we will focus on FAR part 25.1309

The equipment, systems, and installations whose functioning is required by this far 25.1309.

it must be designed to ensure that they perform their functions under any operating condition.

The airplane systems and associated components considered separately .

The occurrence of any failure condition which would prevent the continued safe flight and landing of the airplane is extremely doubtful.

The occurrence of any other failure conditions which would reduce the capability of the airplane or the ability of the crew to cope with adverse operating conditions.

It is also describes the possible modes of failure and explains damages from external sources.

It explains the probability of multiple failures.

It is approved by FAA(federal aviation administration)

FAR part 25.1309 is addressable for hardware functions only.

For software operations will be addressed in DO-178A

THANK YOUPRESENTED BY:-SAI SHUBHANKAR