Based on AgustaWestland’s vast experience with helicopter designs over many decades, the airframer has now produced the innovative AW189. The manufacturer has provided a lot of commonality with its previous types – not only in the aircraft and its systems, but also in the approach to safety standards, maintenance and training.
The AW189 is primarily aimed at global offshore and search and rescue (SAR) operations. For SAR, it can be fitted with up to two hoists and nose-mounted forward-looking infrared cameras. This improves on my own SAR experience – that of an operator sitting in the back of an aircraft looking at a large screen. The aircraft has already been selected by Bristow Helicopters for its contract to provide UK SAR operations for 10 years from 2015.
However, quick and easy changes can be made for other tasks – such as medical rescue with stretchers, or a VIP interior. A cargo hook and fast-rope system are among other available fittings.
The AW189 is versatile. The aircraft is powered by two General Electric CT7-2E1 engines, each capable of providing 2,000shp (1,470kW), and equipped with dual FADEC and built-in particle separators.
AW189
AgustaWestland
With its powerful engines, modern main and tail rotor design and good performance, the AW189 is efficient across the world, whether in hot, high and heavy or icing conditions. Due to its advanced main rotor blades the aircraft is very fuel efficient, burning about 400kg/h and taking a standard full fuel load of 1,600kg (3,530lb), according to AgustaWestland.
This gives the aircraft good range and a low cost per seat-mile. For example, a flight to 200nm (370km) out and back, with adequate fuel reserves in instrument meteorological conditions can accommodate 12 passengers. At 225km the payload rises to 16 passengers, and at 177km to 18 passengers. Modular extra fuel tanks can be quickly fitted or removed. At maximum weight, the best cruise speed is 135-140kt (250-260km/h).
The AW189 is competing with the Airbus Helicopters EC175 and EC225 Super Puma, and the Sikorsky S92 for payload versus range.
SAFETY FIRST
Both proactive and reactive safety were high on AgustaWestland’s list of design criteria. The aircraft can suffer a single engine failure at any time, throughout the whole flight envelope, with no risk period – unlike most older designs. The AW189 complies with all the latest reactive safety measures, such as crash attenuating seats for all occupants. Upper body restraints are included, with the undercarriage taking the major impact of an excessively heavy landing, followed by the belly, then the seats. The fuel system is also crashworthy.
The cabin should be able to resist to 16g longitudinally, 20g vertically and 8g laterally, and the seats are designed to accept these loads. The pilots’ seats have five-point harnesses. The large doors and windows allow quick and easy exit in the event of an emergency. In the standard 16-seat configuration, there are no more than two seats per emergency exit. The eight passenger emergency windows are also impressively large, so in the event of a crash there is a good chance that all occupants will survive.
Another important safety factor is the 50min dry run capability, should the main gearbox lose all its oil – this is likely enough time for the pilot to find a safe landing diversion. This is also a major improvement on other types, where this period is usually about 30min.
Passenger comfort was also a priority – low internal noise and vibration levels were just two of the criteria. During my flight we took the aircraft to its highest speed, to check vibration levels and noise. The noise level was benign, even with my headset off. The slightly increased vibration level was also benign.
The large doors and windows give all occupants good visibility and a pleasant atmosphere. The doors also allow cargo pallets or other large items to be easily loaded, and there are also 12-, 18- and 19-seat configurations.
Other major design criteria were low operating costs, a low initial purchase price and reduced maintenance hours.
Actual figures will not be available until the aircraft enters service and builds up some hours. However, AgustaWestland has used its experience with previous designs to reduce maintenance per flight hour, and the AW189 is equipped with advanced diagnostic tools to monitor the health of critical components, increasing safety and reducing time on the ground. Thus, a limited number of components are subject to overhaul or retirement based on hours flown; the rest are on condition only. The helicopter utilisation monitoring system (HUMS) is standard equipment, including to track and balance the main rotor. As a result, there is no need to fit and remove the usual Chadwick equipment, thus speeding up the process considerably.
With a roomy, comfortable cabin and cockpit and a large baggage compartment – 2.4m³ (85ft³) – the aircraft will fit comfortably on most offshore decks.
AUXILIARY POWER
The AW189 has the luxury of an auxiliary power unit – a small 60kw engine on the roof which is used for a number of tasks. For example, the cabin can be heated or cooled before passengers embark without the need to start the engines or rotor. The APU provides enough electrical power to start the engines without the need for an external power cart. In the extremely unlikely event of a double generator failure, it will provide enough electrical power to keep all the electrics on line. During my flight, when both generators were switched off all our screens went blank. The APU was then fired up and we got our presentations back after a short delay.
I would not like to experience this in instrument conditions, for which the aircraft is certificated as single pilot. However, there is a small standby instrument with a 3in diameter available to both pilots at the top-centre of the instrument panel, which shows attitude, speed and altitude – a “get you home” facility. However, a pilot would need to be practised in its use – hopefully in the simulator.
TRAINING
A level D full-flight simulator will soon be available at Sesto Calende in Italy, and a second will later be set up in Aberdeen to train SAR crews for Bristow. A third will be used in Qatar by Gulf Helicopters – the current largest customer of offshore-configured AW189s, with 15 on order.
The FAA has approved no flight time requirement in the actual aircraft for pilot conversion – it can all be done in the simulator. However, EASA still requires stick time in the aircraft.
Pilots flying other AgustaWestland types will recognise the similarity of many of the systems, operating procedures and presentations, so will require less conversion training. The simulators are also based on the latest technology, and present hundreds of malfunctions and failures – including three different tail rotor failures, one of the hardest situations for pilots to deal with.
The aviation industry still suffers the occasional fatal crash when pilots have not interpreted the displays properly, or have incorrectly programmed the automation. AgustaWestland takes this seriously, and gives comprehensive, advanced training for both pilots and ground crew at several academies around the world.
WALKAROUND
My pilot was chief experimental test pilot Marco Feller. Our aircraft was number six, and still on “experimental” registration. The southern California weather was fine and cold, with little wind. However, the aircraft was based at the Anaheim Stadium car park, along with several other helicopters and an AW609 tiltrotor. As a result, there were several restrictions for flight operations imposed by the authorities. Very fast backwards, sideways and other manoeuvres were not allowed.
However, Feller assured me that the aircraft will go sideways at 60kt and backwards at 45kt with no control difficulties. This will be comforting for North Sea pilots, who know all about strong wind suddenly changing direction while on the deck or overnighting offshore.
Feller demonstrated a typical pilot’s pre-flight inspection. I noted the high main and tail rotors – personnel are in no danger of being struck by running rotors or blasted by hot air from the engine exhausts, which discharge upwards.
Our aircraft was equipped for offshore operations, so Feller pointed out the external flotation equipment. According to AgustaWestland, the AW189 is stable on water up to sea state six, which is a fairly fierce wave and wind condition in which most helicopters have difficulty in staying upright. The two large, externally contained life rafts are positioned so that occupants can step straight into them without even getting their feet wet, hopefully. The rafts inflate automatically if the aircraft lands in water, and can also be inflated by the pilots.
The pre-flight inspection took less than 2min, and does not require the pilot to climb up and inspect the main rotor and its connections. All the fluid volumes and pressures were easily visible, with one exception – the very important tail rotor gearbox contents. Feller had to call an engineer to confirm that this was part of his pre-flight inspection. It is unusual for the pilot not to have sight of this.
Passenger access to the cabin is easy, with the provision of steps and handrails. Likewise, I found access to the left-hand cockpit seat to be simple. The seat is well designed and comfortable, and both it and the controls are adjustable to ensure everything is in reach. Easy access is important for the pilot in the left-hand seat, since the AW189 is certificated for single pilot IFR operations from the right-hand seat. Again, this is good design.
Vision to the outside is remarkable, and the windscreens are reinforced to mitigate the consequences of a bird strike. Such is the attention to detail.
Marco Feller (left) and Peter Gray
Terry Jones
AT THE CONTROLS
The cockpit is pilot-friendly. It is specifically designed to have a lot of commonality with other AgustaWestland types, such as the AW139 and AW169. The full digital glass cockpit is comprised of four 8in and 10in displays – two for each pilot. These primary displays, larger than those in the AW139, show everything the pilot needs to know. The pilot can bring up a vast selection of information, most of it with a control button on the top of the cyclic stick.
There is also a four-axis dual-duplex digital automatic flight control system and dual flight management system, all designed to lower the pilot’s workload. During my flight I asked Feller to take out the automation and let me fly the aircraft “raw”. The avionics are designed to accept future satellite-based navigation and precision approach systems with advanced communication and surveillance capabilities. The system already provides offshore approach procedures.
I noted the built-in redundancy of major systems – another important safety feature, especially for single-pilot IFR operations. Unlike many other helicopters I have flown, the overhead panel is simple – just a few circuit breakers and the rotor brake. There is no need for the pilot to reach up to reset a popped breaker – it can be done with the electronic control device unit (ECDU), a small control box on the centre console, with one for each pilot. There are no fuel, electrics, hydraulics and other panels – management of these systems is done through the ECDU. Weather radar, maps, flightplan and whatever else the pilot needs can be brought up on the screens with as much or as little information as needed. The pilot can sit back, monitor and direct.
Each pilot has the equivalent of a large “mouse” on the centre console, to navigate the various management systems and displays. I noticed at the bottom of the centre console a lot of empty space for the operator to put whatever is needed. Even without AgustaWestland’s comprehensive conversion training, I could tell during our flight, at a glance, where we were in space, where we were going and our surroundings
START UP
Feller talked me through the start up. He did it from memory, and it was logical, with lots of automation. Although the AW189 is extremely complex, a big effort has been made to keep the pilot’s job simple. And so it was – there is no fuel panel with fuel on/off switches, throttles and the like. The engines are dual FADEC controlled, so the engine start routine is to select “start” and sit back and watch, hands and feet off the controls.
My taxiing and first take off to hover were easy. A 360˚ spot turn with the powerful tail rotor was easily accomplished, with lots of power and control in hand. The AW189 will go round very quickly if desired.
I moved into a 1,000ft (300m) cruise to explore other characteristics. Monitoring the power required and power available was easily done via a small panel on the screen. Feller showed me how to insert cruise altitude, speed, direction and destination into the autopilot, to allow the aircraft to fly itself to our destination, hands and feet off the controls.
Instead of using contractor avionics which go into many other aircraft, AgustaWestland develops its own, to ensure the systems are suitable for their aircraft. We went to maximum continuous power in level flight and achieved 160kt. To explore the characteristics of flight at the maximum permissible, never-exceed speed (Vne) of 169kt, Feller put us into a slight dive. The advantage of flying with experimental test pilots is that they are allowed and authorised to explore, establish and exceed the flight envelope, to ensure a safe flight envelope for us mere mortals. Indeed, for certification purposes, the manufacturers have to demonstrate safe flight at Vne plus 10%. And so, Feller went beyond the Vne for my benefit. The vibration level increased slightly, but not uncomfortably so – even at this speed, modest turns are still safe to perform. Feller could not answer my question why the Vne was 169kt and not rounded up to 170kt, but I forgave him.
VISUALS
We did not have to look outside much since the aircraft is equipped with TCAS2 – an excellent feature for single-pilot IFR. This not only alerts the pilot of other close/nearby aircraft, but also instructs the pilot which way to go to prevent a collision. The pilot is also warned aurally if the aircraft is getting too near any obstruction such as the ground, a tower or a mountainside.
We did steep turns at 120kt, again with no ill effect. This can be a considerable aerodynamic challenge for a lot of helicopters, especially when at high weight. Visibility into the turn is excellent. Unlike a lot of helicopters – some of them fairly modern – the aircraft can sustain a 90˚ bank, even at high speed. This demonstrates the excellent airworthiness characteristics, and also gives the pilot confidence if he has to suddenly turn at high speed.
Autorotation at the best rate of descent speed of 80kt produced a rate of descent of 2,700ft/min. This is comfortable for the pilot to control.
I asked Feller to demonstrate rapid up and down movement of the collective pitch lever while I watched the rotor RPM. He was fairly vicious, but the RPM moved no more than 1%. This demonstrates the excellence of modern FADECs, and how far modern gas turbine engines have equalled the acceleration and deceleration responses of piston engines – there is no difference.
GOING RAW
Feller then disabled all the stabilisation equipment to allow me to fly the aircraft “raw”. Some modern helicopters can suffer from pilot-induced oscillation, known in the trade as PIO. But I did not have PIO on this aircraft – I had to concentrate, but was able to control the aircraft accurately. There was a bit of wobbly aircraft movement, but nothing excessive. I was able to control heading, height and speed accurately enough, although I would not like to fly the aircraft in this state for very long – such as from a 320km offshore platform. Such is the redundancy of these systems that such a failure is very remote, although I would need some practice onshore before attempting to land on an offshore platform in this condition.
I asked Feller if AgustaWestland had explored settling with power/vortex ring state. This is an aerodynamic problem resulting from a combination of low speed, a high rate of descent and fairly high power applied – such as during a poorly flown approach. The main rotor quickly loses a lot of lift and the aircraft accelerates down. Directional control can be reduced and the aircraft heading can swing from side to side.
Some pilots, unaware of the condition, will pull more power to try to decrease the rate of descent, but in the worst case the whole rotor will then stall. There is no recovery. While some helicopters give lots of warning and have benign characteristics, others do not – so, I was disappointed when told that none of the certification authorities or AgustaWestland require an examination of settling.
The AW189 can carry out an automatic, hands-off instrument approach down to 50ft over the runway. However, because we were operating out of the stadium car park, we carried out a steep approach instead to the hover square. Visibility over, around and below the instrument panel was sufficient to avoid having to cock the nose sideways, as in a lot helicopters, to keep the helipad in sight throughout.
Shutdown was methodical and logical, again with no checklist.
The AW189 is the latest in modern helicopter technology, with customer, oil and gas producers' and other criteria incorporated into the design. It has all the required safety features and is very pilot-friendly, despite its complexity. Its powerful engines and sleek design – particularly of the main rotor – will ensure safe and efficient performance worldwide.
Source: FlightGlobal.com
