|
An Air Data Unit is used to provide data on airframe Static/Pitot Air Pressures and Air Flows. This data is used to provide information such as airspeed, acceleration, altitude to other aircraft/engine systems for correct and optimal control of the aircraft. The unit is software configurable to allow use on a variety of Airframe specifications. The SCADU is a safety critical, real-time, embedded system, which requires design, test and certification to RTCA DO-178B Level A.
participation in the project was to provide an independent/managed test resource for validation of the SCADU’s data collection and processing software. The software under test was written in ANSI C and the unit test scripts were written using LDRA’s Testbed suite for C/C++. This tool enables the tester to write test scripts to stimulate the embedded software and compare actual and predicted results. The test scripts were written to give a clear pass/fail criteria and indication of the overall test coverage for the unit under test. The project achieved successful CAA/FAA certification.
The project’s function was to take the documentation, in the form of low level design psuedo –code (PDL), and generate test cases that proved the code correctly implemented the requirements (Black Box Testing).
Once all black box tests have been written the code and coverage data is reviewed to ensure that all the PDL functionality has been tested and all code has been covered. Where omissions are found the tester will generate new test cases (White Box Testing) and raise a problem report to the client identifying the drop-off in the documentation set.
The test cases were written to achieve 100% coverage of all statements, decision branches, boolean operators and so ensured full functional compliance.
Testing was initially carried out in the HOST PC system where the tests were developed, but was also run on the TARGET platform to ensure that there were no anomalies in the target compiler or hardware environment.
|
Over 2 years experience of testing C code to Do178B Level A at Module Level Using LDRA’s Testbed. |
|
The client was able to pass across the project responsibility for the module testing to , allowing him to use his resource in developing the application. |
|
Over 15 years experience of Validation and Verification of Safety Critical systems to Do178B Level A |
|
The client was given a fixed price for performing the testing which suited his budget constraints. |
|