Just over 10 years on from the signature of a combined development and production contract for the A400M, one of the programme's first pair of customer aircraft is making its public debut.
The appearance at Le Bourget of aircraft MSN8 has some similarities with that of the A400M development example that took part in the last Paris air show. It will make a brief flypast of the site, before touching down and taking its place on the static display line.
But, unlike in 2011, the limited flying time will be intentional, and not the result of a gearbox issue, which restricted operations as the show loomed two years ago. With the future French air force aircraft having only performed its debut flight in Seville, Spain on 7 June and the type yet to enter operational service, the A400M's display commitments will instead be met by an Airbus Military crew flying a "Grizzly".
Traced to a crack in an idler gear caused by greater than expected vibration levels encountered earlier in the programme, the issue has now been resolved, via the use of a thicker gear wall by Italian supplier Avio.
"We know what the issues were, and we've deliberately mitigated against those," says Simon Henley, president of the Europrop International (EPI) consortium responsible for delivering the aircraft's TP400-D6 turboprop engines. "We've now got a gearbox that we're very comfortable with," he adds, describing Avio as "a very strong partner on the programme".
With a need to handle a maximum available power of 10,700shp (7,980kW) per engine, or just over 11,000shp for "hot and high" operations, "There's an incredible amount of power density in that gearbox," he notes.
The result of a four-nation collaboration between Snecma (with a 32% stake), Rolls-Royce (25%), MTU (22%) and ITP (21%), the three-shaft design drives an eight-bladed Ratier-Figeac propeller more than 5m (16.4ft) in diameter. Total engine weight is 908kg (2,000lb).
EPI secured full civil certification for the engine during 2011, the first time that the propulsion system for a European military aircraft had gone through the process with EASA. More than 27,000 running hours have been accumulated to date, including in excess of 17,000 flight hours powering five development and two production aircraft. "Our lead engine has about 1,500h, and we are seeing no performance deterioration," Henley says.
By 21 May, the company had delivered 28 engines for use with Airbus Military's five-strong fleet of "Grizzly" development aircraft, plus 16 for production aircraft up to MSN10: the last of four A400Ms to be handed over to customers this year. The company has also delivered initial spare engines for the French air force.
In addition to the gearbox resolution, EPI has also addressed a bearing cover plate issue encountered during flight test. The problem - which last year interrupted a vital phase of so-called function and reliability testing - has led EPI to already test the maximum capacity of its production set-up for the engine during a retrofit activity performed on MTU's final assembly line in Munich, Germany. This has five main production docks, and a normal staffing level of around 30 personnel.
"We have already been running at 10 engines per month for a couple of months," says Gerhard Bähr, the company's TP400 programme director. "That is a level we were due to achieve in 2015, at full-rate production."
MTU achieved the surge in activity by drawing in engineers working on the Eurofighter's Eurojet EJ200 turbofan engine and providing engine MRO activities for other military types, including for the Panavia Tornado elsewhere on its site, which in total employs around 5,000 people across all programmes.
"That was the intention, when we brought all the programmes that we have to Munich," says Bähr. MTU had previously performed the final assembly of early TP400s in Berlin.
It now takes 35 days to assemble, test, qualify and ship a TP400, having fallen from 50.
Airbus Military in February disclosed that the engines on the first three production A400Ms would be changed after two years as a result of retrofit requirements. A critical design review will be performed in June on a new alloy casing, which will resolve an excess heating issue on the engine nacelle, also discovered during flight testing.
Affected engines will be stripped to modules and have the part replaced in a retrofit programme which will be "as near as possible invisible to the engines," says Henley. "That will get us to the [engine] design life of 30,000h."
Unusually, the TP400's full authority digital engine control system manages the whole propulsion system, also including its propellers, nacelles and bleed air.
Capabilities including a health and usage monitoring system and a built-in test for lifetime management will be added, following the first production aircraft. "We will be on-condition throughout the life of the programme," he says.
Design innovations including the use of blisks - single machined pieces, rather than multiple blades - in the intermediate and high-pressure compressors - respectively produced by MTU and R-R - have helped to reduce weight and increase durability. The German company in mid-April opened a new blisk production facility in Munich, which in time will manufacture up to 3,500 units per year, predominantly for use with commercial aero engines.
"There is no doubt we have got a state-of-the-art engine," says Henley. Fuel consumption is "better than specification by some margin", he says, citing a figure of more than 1%.
Looking towards air force operations with France, an industry arrangement at Orléans air base covers spares provision and on-site repairs, with a 24h advice service also to be available with EPI and its partner companies. EPI is already in talks with Turkey and the UK for similar arrangements.
"Our focus for the rest of this is on in-service support," says Henley. "Then the big deliveries can start." By the time Airbus Military achieves full-rate production of the A400M in 2015, EPI will be delivering the engines for individual transports just one week before they are due to be installed on the wing. With current orders, it will deliver almost 1,000 TP400s, but more could follow.
"I'm very optimistic about the export opportunities," Henley says. "It's a niche aircraft, but it's a niche that's right at the heart of the military requirement."
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