It has been six years since the first flight of the Airbus A400M airlifter, known as the Atlas to the Royal Air Force but ‘Grizzly’ to its flight test crews. Over 20 production aircraft have now been delivered to five customers in Europe and Asia.
Initial flight testing focused on setting the A400M’s flight envelope, but this work is now complete and the test program has shifted to role expansion, including air drop (containers and paratroops), inflight refueling and unpaved runway operations. Testing of the Defensive Aids Sub-System (DASS), vital to ensuring the safety of the aircraft when operating in a threat environment, is also underway.
Despite some recent setbacks, including an operational pause following the loss of one A400M on its first post-production test flight last May, the five dedicated test aircraft had accrued over 7,900 flight hours and 2,900 flights by mid-October 2015.
The transition of flight test away from aerodynamic testing to role expansion has already seen the retirement of two of the test fleet and a third will gain a new lease of life as an Airbus company demonstrator in the near future.
Designing a flight test program
The A400M is designed and certified to civil standards, complemented by specific military requirements where necessary, but it is of conventional design. The primary structure is constructed largely of aluminum alloys, with titanium alloys used in highly loaded areas such as the wing to fuselage carry-through structure. Glass- and carbon-fiber reinforced plastics are not used in the primary structure, instead finding application in lightly loaded components such as aerodynamic fairings.
Many of the A400M’s systems are based on those of the A380, and the Grizzly flight test program has been able to leverage the work performed in Toulouse, France for certification of Airbus’s commercial program. In fact, aspects of the early A400M customer flight crew training were performed on the A380 simulator in Toulouse until a dedicated A400M simulator was commissioned in the Airbus Defence and Space (formerly Airbus Military) training center in Seville, Spain.
When designing the A400M flight test campaign, Airbus broke with tradition and established two test sites, one in Seville and the other at the Airbus Flight Test Center in Toulouse, to conduct simultaneous flight test activities.
“The difficulty of operating the airplanes from two bases was a concern for us before we flew, because we had to ensure that the processes and procedures we applied were consistent and we had to coordinate activities in two locations correctly,” said Fernando Alonso, senior vice president Airbus Flight and Integration Tests and head of flight operations, at the height of the test campaign in 2012.
“The distance between Seville and Toulouse has not prevented us from optimizing what activities each airplane was doing on each day,” he continued. “If an airplane was unserviceable in Seville and the tests were critical, we were able to conduct the tests with the Toulouse airplane without any problem.” Today Alonso is head of military aircraft at Airbus DS.
The A400M flight test program is a collaborative effort between Airbus and Airbus DS and the crews often fly together as part of a mixed team. To assist with the receipt and collation of flight test data, the company established a telemetry network across Europe, with ground stations in Madrid (Getafe) and Seville in Spain, Bremen and Hamburg in Germany, Toulouse in France and Filton (near Bristol) in the UK.
Initial planning concluded that six prototype aircraft would be built and dedicated to the fight test campaign; however it was subsequently decided that only five would be needed and one aircraft (MSN5) was not built. The first two prototypes, MSN1 and MSN2, were heavily equipped with flight test instrumentation (FTI) and another pair (MSN3 and MSN4) had a medium FTI fit. The final test aircraft (MSN6) is only lightly instrumented and, as it was completed close to the final production standard, was used for function and reliability testing in 2012, prior to type certification in March 2013.
With the transition of the campaign to role expansion, the subsequent reduction in flight test activity has resulted in the retirement of two test aircraft, the first (MSN1) in November 2013 and the second (MSN3) in October 2014.
“MSN2 is currently dedicated to DASS flight testing, MSN4 is more focused on airdrop operations because it is the only test aircraft fitted with an operative cargo loading system, and MSN6 is used for paratroop flight test,” explains the current head of flight tests and operations, Eric Isorce.
“In 2016 we aim to fly around 800 flight test hours. We plan to retire MSN2 in the middle of the year but we have the capacity to extend it in operation if we need to and MSN6 will be retained by the company for marketing purposes,” explains Isorce.
Tactical role capability expansion
Production A400Ms delivered to the end of 2015 have a basic cargo capability, enabling customers to undertake crew training and logistics flying, while the flight testing effort concentrates on expanding the aircraft’s roles into the tactical environment.
In 2014 the A400M was cleared for all flight operations down to an altitude of 150ft, in Day VMC (visual meteorological conditions) and 300ft in Night VMC in manual mode, using the aircraft’s enhanced visual system (EVS) and night-vision goggles (NVG). The EVS projects infrared imagery from a camera in the nose of the aircraft to the head-up display in front of each pilot.
The next step will be to certify the aircraft using the terrain-following systems to low altitudes in instrument meteorological conditions (IMC).
During the past year a great deal of flight test work has been undertaken to expand the functionality of the A400Ms DASS system. This included a background recording campaign for the Missile Warning System Passive Element (MWS-PE) infrared sensors with additional dedicated test flights in conjunction with fighters (afterburner plume recording), and low-level flights over industrial areas in Germany, as well as the recording of the launch of flares from the A400M itself.
In all, 11 DASS test campaigns had been carried out by the end of September 2015 in Cazaux, France; Manching, Meppen, and Greding, Germany; and Moron and El Arenosillo, Spain to certify and initially qualify the DASS systems, including the Defensive Aids Computer (DAC), Expendables Dispensing System (EDS), Radar Warning Receiver (RWR) and MWS.
In parallel with this activity has been the testing of the DASS system using two production aircraft destined for the UK, as RAF A400Ms have a unique DASS fitted.
The next test campaign, to be conducted in the second quarter of 2016, will be the full performance of the RWR and MWS.
A fourth unpaved runway operations test campaign was undertaken in September and October 2015 at Écury-sur-Coole in central France, where the A400M was tested during the course of 15 flights and 40 landings on grass and soil.
The outcome of this testing has been to certify the A400M’s footprint for surfaces down to CBR9 (California Bearing Ratio) and the 2016 flight test campaign will be to test the aircraft on sand-type surfaces with low CBR, possibly in the UK.
Paratroop air drop test campaigns were undertaken at Cazaux in 2014 and at Fonsorbes, France in 2015, resulting in the certification of the A400M for military free-fall jumps of up to 29 paratroops from either side door, and up to 12 paratroops from the rear cargo ramp. The original plan called for the qualification of a total of 116 paratroops using the two side doors simultaneously (two ‘sticks’ of 58), but a crossover issue behind the aircraft has delayed this work until the problem is understood and a resolution is found.
Testing of airdrop loads has also continued throughout 2015, including a gravity-assisted Container Delivery System (CDS) drop of up to eight one-ton loads and one platform of up to four tons, using the A400M’s automatic Electromechanical Release Gate (ERG) drop system. In the first quarter of 2016 the plan is to test the full airdrop capacity of the aircraft – up to 24 one-ton CDS drops and platforms up to 16 tons using the extraction parachute method.
Finally, flight testing of the A400M’s inflight refueling system, including the role of both receiver and tanker, have been further tested in the past year. Achievements during this period include the certification and qualification in February 2015 of the aircraft’s ability to receive fuel from both low-speed (C-160 Transall) and high-speed (Voyager MRTT) tankers under day and night conditions.
In the tanker role, the A400M was certified and qualified in March 2015 for day and night refueling operations with two F/A-18 Hornet fighters, using the removable underwing hose pods.
Testing to be carried out during 2016 includes the installation of the optional cargo hold tank (CHT) capability. “The tests are programmed to begin in January 2016, but this will be determined by the progress of other flight tests, because we are using MSN4 for air-to-air refueling testing and it is also the sole aircraft dedicated to cargo drop testing,” explains Isorce.
One test campaign that did not produce the desired results, however, was the testing of an EC225 helicopter as a receiver behind the A400M. The aerodynamic effect of the A400M has caused a suspension of the trials and comes as a blow to Airbus DS, which had promoted its capability as a tactical tanker. See Aerodynamic effects on page 34 for more about the efforts toward a solution. \
Nigel Pittaway is a freelance aviation and defense journalist based in Australia