Airbus Defence and Space announced this week that it has achieved the first automatic air to air refuelling (A3R) operation using the Advanced Aerial Refuelling Boom System (ARBS), fitted to its A310 multi role tanker transport (MRTT) testbed.
The flight test campaign, conducted earlier this year between the A310 and a Portuguese Air Force F-16A fighter, involved 45 flight test hours and 120 dry contacts, covering the entire refuelling envelope. The milestone clears the way for the certification of the A3R system, which will take place through 2021.
Airbus announced at the Singapore Air Show in February that the Republic of Singapore Air Force will become the launch customer for the system, for its fleet of six A330 MRTT aircraft, with deliveries beginning immediately after the conclusion of certification in 2021.
Australia is also watching the program closely and has previously contributed one of the RAAF’s KC-30A MRTTs to the earlier flight test campaign, representing a large aircraft receiver during at least seven automatic contacts with the A310’s ARBS.
Airbus DS head of business development & program portfolio of Military Derivatives Antonio Moya says that fuel transfer (‘wet’ contacts) were not part of the recently completed test campaign because the current MRTT fuel management is already fully automatic.
“The operator only sets receiver and fuel amount into the MRTT’s computers and, once the contact is confirmed, the system starts transferring fuel. It is stopped after the receiver has taken the selected amount of fuel or if there is an abnormal event,” he said.
“In the latest flight test scope, we are developing the rest of the automatic functionality, to automate the full operation. This consists of automating the ARBS flight control system to align it with the receptacle on the receiver aircraft, to monitor receiver stability in real time to determine the optimum moment to extend the telescopic boom and perform connection with the receiver; and then to separate the boom from the receiver at the end of fuel transfer by retracting the telescopic beam and flying the boom away.”
The earlier trials, conducted in 2017 and 2018, were part of a feasibility phase to demonstrate that Airbus’ technology was mature enough to develop an A3R system.
“In that phase we focussed just on the contact itself; because the contact is the most difficult task to automate. We had to demonstrate that the system was able to align a flying boom with the receptacle of a moving receiver with an accuracy of just a few centimetres. If you cannot do it, then you are far off an A3R solution,” Moya added.
“In this milestone, we are not just talking about one contact in optimal conditions for a photo. We have performed more than 120 contacts and disconnections during this phase, covering the whole AAR envelope of the MRTT and F-16A as receiver.”
The A3R system involves both hardware and software upgrades to the MRTT but requires no modification to the receiving platform. After certification, new MRTTs will be delivered with the modifications should the customer request it and Airbus DS is now working on developing a retrofit package for existing aircraft, with the intention that work will be done at an approved maintenance and repair organisation (MRO) facility.
“All MRTT customers have shown their interest in this functionality, as it is a clear step forward in boom operations and will shape the future of AAR,” Moya said. “Up to now, only Australia and Singapore have been actively working on A3R with us, but we expect that several customers will sign up for it very soon.”