Air Force Base Overberg (formally Test Flight and Development Centre) is responsible for all developmental test flying in the SAAF, as well as test flying for SAAF acceptance of airborne systems.
One of the more important types of testing that consumes a lot of time (and therefore budget) is testing of an aircraft’s communications system. Specifications for communications equipment always include communications range and quality. The range requirements differ for the different types of radios on board (HF, VHF, UHF, etc) and the mode of the individual radio (low/high power, encrypted, hopping, etc), among other requirements. In order to ensure the results are a true reflection of the capability of the system under test, the reference equipment (against which the requirements are measured) needs to be calibrated.
Traditionally, this calibrated radio equipment was housed in a fixed building at AFB Overberg. The aircraft then had to fly to the prerequisite distance from the ground facility, in order to test that the communications system meets the range requirements at different settings and over the entire frequency range. Apart from the wasted time and fuel to get to the test area, the aircraft has to return to the base over the same distance in order to rectify possible problems. Several years ago the Flight Test Instrumentation and Engineering personnel at AFB Overberg decided to place calibrated radio equipment into a container, which could then be transported to the specified range from the base for testing, and therefore, save flight time to and from the test area.
The container, however, needed a specialised towing vehicle, and was bulky and had become unroadworthy. The Flight Test Support Section at AFB Overberg identified a need for a more cost-effective and ruggedised mobile container, complete with installed communication equipment and accommodation facilities that could more readily be deployed for future communications testing. The concept of using a mobile test facility had already been demonstrated in the old container, with the communications testing of the Astra aircraft during the 90s. The new container was therefore planned to be designed, built and tested in time to be utilised for the testing of the Oryx communications suite as part of Project Drummer.
A user requirement specification (URS) was drawn up in September 2011, which described the requirement in detail. The new Mobile Communications Test Facility (MCTF) was to be self-sufficient when deployed for up to a period of five days with two personnel. This meant that apart from the radio test equipment on board, there also were requirements for accommodation, cooking and ablution facilities. It also had to be deployable without a specialised transport vehicle, and be self-sufficient in terms of water, power and spares. Many flying hours could be saved in this way, as the aircraft under test could commence testing almost immediately after getting airborne, instead of flying to a test area first, which could be between 100 and 200 nautical miles away. The turnaround times between flights and maintenance activities could also be dramatically shortened, as the aircraft did not have to ferry back the 100 to 200 nautical miles to the airfield.
As a risk reduction exercise, the equipment and layout was initially tested in the old container before detailed design of the new facility commenced. The configuration decided on was a ruggedised trailer, with supporting equipment transported in a separate, double-cab 4×4 vehicle, which would also tow the trailer. Apart from the communication test equipment, the trailer was equipped with a two burner gas stove, a sink, fridge/freezer, water tank, geyser, chemical toilet, shower, generators and sleeping berths.
A task was registered at Director Systems Integrity, and the Flight Test Support Section at Air Force Base Overberg received the first components for the MCTF on 20 July 2012. The development of the MCTF was finalised within 66 working days, and successfully demonstrated as functional and operational deployable to the quality section of ARMSCOR on 28 November 2012.
The total cost of the project is equivalent to approximately eight Oryx or four Gripen flight hours. The first planned deployment will be in support of the Oryx testing as part of Project Drummer later during this year.
When the trailer is deployed to a distance of 150 nautical miles from the base, communications test ranges of 100 to 200 nautical miles can be verified without the test aircraft flying further than 50 nautical miles from the base. This saves on dead flying time and also allows swift configuration changes and necessary adjustments to the aircraft communications equipment. The utilisation of the MCTF for communications testing in the future pays for its development many times over in terms of time and money.