Avionic Testing

Introduction to Avionics Testing

In line with federal regulations, an avionics system is tested for the first time during the manufacturing process. It is worth noting that production of such materials without operational tests is really not possible and that is regardless of the legal requirements. In the course of the manufacturing process, checks are carried out during the assembly of the product, and in conclusion, a final test is carried out. For students focusing on aerospace engineering dissertation help, understanding these rigorous testing procedures is crucial for grasping the industry's safety and quality standards.

These tests that are carried out during assembly are usually not representative of all the measurements that could be performed. Equipment is, for instance, not tested under relative humidity and even under temperature variations. Such tests usually are performed during the design and development stages (Anon, n.d.). Temperature testing could be performed on all factory units for purposes of inducing early failures using the IFF-7300S Series. From time to time, the examination for military avionics includes both temperature cycling and burn-in.

Avionics Systems and components go through additional tests once they have been installed on aircraft in line with federal regulations. It is quite common for individual components to function alone correctly and fail to operate as expected when in systems.

The goal of testing embedded avionic systems is to prove the capabilities of the software in satisfying what is required. Another goal is to show the removal of errors, which could bring about unacceptable failure conditions if not checked. Requirement-based testing is the most effective in the revealing of mistakes and is commonly used. As such, for the satisfaction of the testing objectives of airborne software in line with the DO-178B standard;

he primary basis for test cases should be on software requirements

For the establishment of conditions capable of revealing potential errors and also for verification of correct functionality, test cases are developed.

Through software requirements coverage analysis, the software requirements not tested should be determined.

The software structures not exercised in the course of testing should be determined by structural coverage analysis.

Conformance Testing for ARNIC-653 Standard

In 1997, ARINC (Aeronautical Radio, Inc) developed the Avionics Application Software Standard Interface ARNIC-653. This standard defines the application program interface APEX (Application/ Executive) between application software and the operating system of the avionics computer. The standard is, at present, chosen as the primary standard for implementation in embedded avionics systems` real-time operating software (RTOS) (Sonnenberg and Dewey, 2009). For support of the requirements-based conformance testing and further simplification of the process of certification for off-the-shelf software products, the ARINC-653 standard contains Part 3 – Conformity Test Specification. This specification includes a description of test cases that checks the functionality of RTOS application program interfaces on conformance with the Part 1 requirements of the ARINC standard. The ADS-B INTEGRITY tool could be used for carrying out accuracy and performance tests.

Pilot`s Squawk

There are other additional reasons for testing, for instance, whenever complaints are registered on squawk sheets by pilots. Some failures are noticeable like the "DME inoperative," while there are also other squawks like "DME erratic" and "DME distance is off." The avionics system removes the DME given that "off" is not a quantitative term and operates it with signal levels and distances that are known to try to establish the true meaning of erratic and "off" (AvionTEq, 2019). Calibration of the equipment is done when the technician does not find any problem and they go ahead and return the equipment to service. The inability to replicate the squawk is referred to as "no-fault found" and is usually representative of significant expenses to the avionics industry. There exists a high likelihood that a pilot could have experienced problems with DME. However, the real causes of the issues could be ground station faults that lower the efficiency of replying and high levels of air traffic.

In those instances, when complaint results are a No Fault Found (NFF), technicians could force the faults through the stressing of the equipment. That involves the application of vibrations, heating, and even power supply voltage that is varying. Such procedures lift the cost of the NFF as they increase the technician time and typing up test sets. It is, however, worth noting that there is a possibility that this could be significantly less than subsequent removals and checks for the same problems that are not definable. The removal of a black box and its further shipment to shops for servicing is a fit that most airline companies find to be quite expensive. And that is mainly when no fault is found. Such processes also increase the number of costly spares required on the shelves if the fleets are to be kept in the air. There are instances when systems will be put to the test even when there are no squawks. Such occurrences are done in line with the regulations of the FAA. Electronic equipment tends to degrade bit by bit without being noticed. And that is why they need to be tested habitually as a precautionary measure. During pilots' initial flying lessons, they are taught how to go about checking magnetos before taking off. That is done in such a way that they never have to wait until someone writes them on the squawk sheet (Software Testing for Embedded Avionics Systems, n.d.).

It is worth noting that with the various avionics systems on aircraft, a lot of time would be required to test each one of them. And just like with magnetos, the majority of the systems are redundant, and the failure of one leaves the aircraft with no losses of neither communication nor navigation. The majority of the systems are, however, complex, and there are dangerously significant possibilities of failure.

Testing Frequency

Periodic testing is, in most cases, quite prudent and a requirement of the law. At all times, when carrying out a test, the needs of the Federal Aviation Regulations (FARs) must always be met, and such requirements often differ, and that depends on the applicable rules. Only a few avionic systems require to be tested regularly, and FAR`s mandated performance levels have been observed to be less than the capacity of the equipment.

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References

AvionTEq. (2019). Introduction to Avionics Testing. [online] Available at:

FAA (n.d.). Chapter 236. Evaluate Avionics Test Equipment. [Online] Available at:

Software Testing for Embedded Avionics Systems. (n.d.). [ebook] Institute for System Programming of the Russian Academy of Sciences (ISPRAS). Available at:

Sonnenberg, W., and Dewey, M. (2009). Consolidating Test Resources for Avionics Production Test – Requirements and Applications. [ebook] Available at: