Search for a theme covering helicopters in development and you quickly find that the new super-medium category is dominating the thoughts of three of the four big Western manufacturers.
It is a segment that did not previously exist, but now three of the airframers are working on rotorcraft in the narrow bracket between 7t and 9t. Two of the three - certification hurdles permitting - should enter service this year, and the third is scheduled to follow, with a similar caveat, around two years later.
The driving force behind the development of this new weight class is the offshore transportation sector, which, in turn, is being spurred to achieve new standards by the oil and gas sector that it supports.
Its demands are fairly straightforward, albeit not always compatible: safety, speed, power, range and capacity all need to be combined to achieve its needs. Which brings us to the AgustaWestland AW189 and Eurocopter EC175, which are both aiming for certification in the second half of the year.
Eurocopter's EC175 is aiming for certification in the second half of 2013
AgustaWestland's aircraft should arrive first, with EASA approval scheduled for the third quarter. The Anglo-Italian airframer would not be drawn on an exact date - and there is an outside chance of it receiving certification by the Paris air show - save to say it will happen in a "matter of months".
The second prototype aircraft recently returned from the USA to Italy having completed a number of key trials on the other side of the Atlantic, including hot-and-high tests and icing trials in Texas and Alaska respectively.
Five aircraft are now flying, comprising four prototypes and a pre-production example, with a sixth due to emerge shortly as it moves to testing of the type's mission systems.
Bristow Group will take the first of the 8t maximum take-off weight (MTOW) helicopters, configured for offshore transport, from a total order for 16 of the type.
Bristow is a key client for AgustaWestland, as it will also become the first operator of a search and rescue variant of the AW189 on the back of its victory in the UK's Long SAR contest. Its bid - using the AW189 and Sikorsky S-92 - was selected in March and will see its UK subsidiary Bristow Helicopters operate 22 new rotorcraft - 11 of each type - to replace UK Royal Navy and Royal Air Force Westland Sea Kings from 2015.
AgustaWestland describes the offshore and search and rescue markets as "a priority" for the AW189. It adds: "The offshore market has rapidly expanded in the last few years. Oil and gas customers are demanding an increasing number of modern aircraft with a growing trend for longer-range requirements, especially in Asia.
"The AW189 is designed to cope with those requirements. Where you don't need to carry 20 people or operate a 12t helicopter, the AW189 is the best possible platform," it says. "It will be very cost effective."
For Eurocopter, meanwhile, work continues on its EC175. Although it cedes 500kg (1,100lb) in MTOW to the AW189, it boasts a cruise speed some 25kt (46km/h) higher and can transport up to 16 people in its 12.3m³ (434ft³) cabin.
The type will also make its debut in an offshore configuration, with three operators - Héli-Union, UTair and Noordzee Helikopters Vlaanderen - vying to receive the first delivery. Two flight-test prototypes have been used for the certification campaign, alongside a single production example. A further 10 aircraft are in various stages of completion at the manufacturer's Marignane site in the south of France.
Dominique Maudet, Eurocopter executive vice-president global business and services, says the EC175 is a "key product" for the company. It has received firm orders for 46 units from four operators and one lessor, with over 100 helicopters covered by letters of intent or options.
"We have many customers who are very interested in the EC175 and it is my expectation that we should get an additional 20-30 orders this year," says Maudet.
It performed a demonstration tour in the USA in March with the first production example - liveried in the colours of Bristow Group - to show off the type's capabilities to would-be customers in the region (Texan firms Halverson Group and ERA Group both hold tentative commitments). It is likely to follow this up by conducting a tour of Asia later this year, encompassing Malaysia, Vietnam and Hong Kong, says Maudet.
However, he is quick to stress that it will not be promoted in mainland China, where its development partner Avicopter will later introduce its own version of the EC175 called the Z-15.
Bell Helicopter too is pushing into the segment with its 525 Relentless, due for certification in 2015. Although some industry watchers have questioned its timing - with one wag dubbing it the "five-too-late" - Bell maintains that two additional years of development will allow it to benefit from more mature technology, such as fly-by-wire controls and Garmin's G5000 touchscreen avionics suite. The 8.2t Relentless, powered by a pair of General Electric CT7-2F1 turboshafts, will be able to transport 16 passengers over 400nm (740km) at a speed of 140kt, says Bell.
Meanwhile at the lighter end of the weight range, AgustaWestland is continuing the flight test campaign on its 4.5t AW169 light-intermediate twin. Billed as an all-round utility helicopter, it is due for service entry next year. One of the four prototype aircraft was recently dispatched to its Arlington, Texas facility to conduct tests of its hot-and-high performance.
AgustaWestland describes the Pratt & Whitney Canada P210A-powered rotorcraft as the "answer to replace ageing platforms in the same category". In addition, the manufacturer argues that operators of other members of its aircraft family, such as the AW139, will benefit from reduced training and maintenance costs if they also utilise the AW169 through cockpit and parts commonality.
Of the four big Western manufacturers, Sikorsky, however, is the exception, with no new civil product in development. For the moment, it is concentrating on ramping up production of its S-76D, which gained certification from the Federal Aviation Administration in October 2012.
The S-76D, with an MTOW of 5.3t, sits just outside the super-medium weight segment. However, Sikorsky says it has no immediate plans to address the gap in its range between the S-76D and the 12t S-92.
"We like our positions in both the medium- and heavy-weight classes, and see plenty of growth in both segments for the foreseeable future. In the offshore oil market, the S-92 continues to meet our customer needs as oil exploration heads farther and deeper out to sea, and we expect that trend to continue for the foreseeable future," it says.
In addition, Sikorsky is making a number of performance enhancements to the S-92. It recently gained FAA approval for a new automated rig approach system on the helicopter and is working on an avionics upgrade and an increase in maximum gross weight to 12.6t.
Near-term slot availability for both the S-76D and S-92 are "essentially sold-out", it notes, with a backlog stretching out to 2015. "That's a good indication of the strength of our products in their respective segments," it says.
Further east, Russian Helicopters is also working on a new aircraft. The Kamov Ka-62 is a rarity in that it lacks the design bureau's trademark co-axial rotors and is equipped with Western-made systems, including its engines. It is on track to make its maiden sortie at this year's MAKS air show in August, says the company.
It has received the rotorcraft's first Turbomeca Ardiden 3G powerplants and these will shortly be installed on the initial flight-test prototype being assembled by the Progress Arsenyev Aviation Company in Russia's far east.
It is aiming for certification of the 6.5t helicopter in 2014, with entry into service scheduled for the following year.