Built in Belgium and aimed at the Approved Training Organisations, the latest iteration of the two-seat Sonaca 200 is equipped for instrument flying | Words: Dave Unwin – Photos: Keith Wilson
Some mornings are just made for flying, and as I ease into a very tight echelon port with the camera ship this morning is clearly one of those.
The day had started with a degree of déjà vu. I’d met up with photographer Keith on a stunning late spring morning at the lovely grass airfield of Fenland in Lincolnshire, and from a distance the test aircraft looked very much like the South African manufactured TAF Sling kitplane we’d flown and photographed from the same airfield last year.
In fact, the test aircraft is a Sonaca 200 Trainer Pro, the latest?and fully loaded?iteration of the Belgian two-seater built by the huge industrial consortium of Sonaca Group in Namur, the capital city of Wallonia.
Although the Sonaca 200 bears more than a passing resemblance to the Sling 2, up close it soon becomes apparent that the 200 is a very different machine. Whereas the Sling is primarily marketed outside SA as a kitplane, the 200 is an EASA approved factory-built VLA.
As such, the 200 has been extensively redesigned to meet the far more stringent regulations of CS-VLA (Amendment 1). The differences between these regulations and the standards applicable to homebuilt aircraft are beyond the scope of this article, but it’s obvious that a kitplane and a factory-built aircraft are not the same thing?even if they may look superficially quite similar.
The Sonaca is available in two versions, the ‘Trainer’ and the ‘Trainer Pro’. The test aircraft is the latter version, which?with its all-glass cockpit and fully integrated avionics?is aimed at the burgeoning professional flight training market.
Closer inspection reveals the dorsal fillet, ventral strakes and large wing fences at approximately mid-span that distinguish the Sonaca from the Sling. These aerodynamic tweaks are to enhance spin recovery and improve aileron response near the stall, ensuring compliance with the aforementioned CS-VLA (Amendment 1).
Most of the differences are actually under the skin. Sonaca claims that around eighty per of the structure has been redesigned to meet market requirements on the one hand, and EASA certification requirements on the other.
The main wing spars, the joint with the fuselage and the carry-through spar have been redesigned, and some aluminum alloys have been changed to take account of higher aerodynamic loads, material fatigue and enhanced corrosion resistance.
These alterations have allowed an increase in MAUW (maximum all-up weight) of 50kg to 750, with a +4.4 g limit load factor. Other changes include strengthening the canopy arches, undercarriage and vertical and horizontal tail surfaces, installing a different propeller, and redesigning the instrumentation, brakes and
fuel system.
The 200 certainly looked very smart, while its bare metal finish glowing gently in the spring sunshine vaguely reminded me of a mid-1950s USAF fighter. Starting at the spinner, the three-blade DUC Flash-R prop is spun by a neatly-cowled 115hp Rotax 914 UL turbocharged air/liquid-cooled flat-four.
Fuel is carried in a pair of 73-litre tanks, one in each leading edge, at the wing root. The wide track/short wheelbase undercarriage consists of an articulated nosewheel (steered via the rudder pedals) which is suspended from a telescopic strut, and mainwheels fitted with hydraulic disc brakes.
The mainwheels are carried by a low-maintenance, aluminium-alloy arch on either side of the fuselage. This arrangement prevents deformation of the fuselage during a heavy landing? always a possibility for a hard-working trainer. All three wheels are closely spatted.
The ailerons and elevator are actuated by pushrods with cables for the rudder. Elevator trim is manually actuated while the large-span slotted flaps are electric. These have four positions: 0°, 10°, 20° and 30°. Each wing’s leading edge has dual LED landing/taxi lights built in near the tips, with position and strobe lights located below the slightly upswept winglets.
There are ground-adjustable trim tabs on the port aileron and rudder, while the stepped static port is interesting and different. The monococque fuselage is made primarily from aluminium as are the wings, flaps, ailerons, fin, elevator and rudder, with composites used for the tips, cowling and canopy frame.
The 200 looks robust, rugged and ready to work for a living. There’s a plethora of rivets and the skins seem quite thick, while well-designed quick-access hatches and jacking points are ideal for ease of maintenance.
The aircraft not only looks new but also modern?and this is important. Most airline industry analysts are predicting a chronic shortage of pilots over the next ten years, and it could be a boom time for the expanding airline academies.
It must be quite disconcerting for a tyro airline pilot who has just borrowed a six-figure sum from the Bank of Mum and Dad to pay for their training, and on their first day they’re introduced to a machine that is ? literally ? older than their parents!
The Trainer Pro is very much aimed at this potentially lucrative market: its avionics are claimed to be comparable with those fitted in the aircraft students will fly later in their careers, while Sonaca claims to have invested heavily in an advanced support platform which should ensure enhanced after-sales service.
The aircraft is also very nicely finished, which made the white cable ties securing the hydraulic lines to the main undercarriage arches even more incongruous.
The impression of a modern machine is reinforced on entering the cockpit. Access is good, although I wasn’t so keen on using the rearward sliding canopy to help pull myself up onto the wide, non-slip wing root walkway.
Just aft of the trailing edge are sensibly-sited streamlined footsteps, but I think possibly some sort of spring-loaded handle just below the canopy rail would be useful as well, as when you pull on the canopy there’s a considerable side-load. Behind the seats is a big baggage bay that can take up to a very impressive 35kg. The seat backs tip forward for easy access.
Planning to experience the aircraft from the instructor’s perspective, I sit on the right. Settling into the very comfortable seat, I slide it forward (which simultaneously raises it) and study the controls and instruments with interest, as the panel would shame some older airliners. Unsurprisingly, it’s all glass, as even the standby instrument (a Honeywell KI 300 which displays airspeed, attitude, altitude and slip/skid) is digital.
Directly in front of the pilot is a large Garmin G500TXI MFD. This unit’s touchscreen display can be split several ways and is quite amazing. (If you look at the cockpit pictures closely, the right side of the screen is zoomed right out to show the British Isles, while on the left is a synthetic view of the runway. Incredible.)
There’s a neat stack of Garmin avionics in the centre (GTN650 and GTX335), with a very comprehensive JPI EDM 900 engine digital monitoring unit on the right. Beneath the avionics stack is a row of silver toggle switches for the electrical services.
Although there’s a colour-coded line below them to link them to the colour-coded circuit breakers they’re slightly anonymous. I’d prefer the actual switches to be colour-coded and preferably rockers, as for any aircraft rockers are simply less prone to being damaged by an errant boot as you climb in and out.
Below these switches are the pre-selector type flap switch and plungers for the choke and carb heat, with the big Andair fuel selector in the lower section that joins the panel to the centre console. The latter extends aft between the seats and carries a large T-handled throttle lever with a big elevator trim wheel to its left and the park brake behind.
The throttle features a spring-loaded catch (like a jet’s afterburner selector), which must be raised to push the throttle past a detent and up to maximum power. With the throttle at the detent, 100hp is produced, while full power is 115hp. One of the dual carburettors carries a throttle arm position sensor which measures the throttle’s position linearly from ‘0%’ (idle) to full power.
The TCU (Turbocharger Control Unit) uses throttle position, ambient pressure, plenum pressure/temperature and engine rpm to actuate an electronically controlled wastegate to regulate boost pressure in the manifold. The TCU adds boost from the 108% throttle position onward.
Of course, with any turbocharged engine care must be taken not to exceed boost pressure limits, so as well as the MAP display on the EMU (pressure is shown in both analogue and digital formats) the row of annunciator lights above the avionics stack includes both ‘TCU CAUTION’ and ‘TCU WARN’.
From an ergonomic viewpoint the 200 is impressive, as practically all my regular gripes had been addressed. Adjustable seats and four-point harness?check. Different shapes for the carb heat and choke?check. Fuel selector points to the selected tank?check. Flap limiting speeds placarded next to the flap switch?check.
Good use of colour-coding?check. Even the parking brake is orientated correctly! However, it wouldn’t be a Dave Unwin flight test without some bitching and moaning, so to stop you all thinking Pierre had bribed me with a case of Leffe, here are some suggestions:
As the choke and carb heat knobs are so close together there should be a guard over the choke. You only use it on start-up, but if a student inadvertently selected choke instead of carb heat on downwind the resultant ‘rich cut’ could be awkward.
There is no DV panel, which suggests the canopy should have an intermediate stop to allow the aircraft to be flown with it partly open in-flight. The aircraft does have excellent air vents; cabin heating and canopy demist (it’s almost car-like) but I still like to be able to see out if there is?for example?oil all over the windscreen.
Plus, it’s just fun (and also cooler, both literally and metaphorically) to be able to fly around with the canopy at least partly open.
Probably the biggest omission is the lack of stick-mounted electric pitch trim. I’m generally against electric trim in small aeroplanes?and to be fair, the big wheel between the seats is nicely geared and works well?but tyro airline pilots will soon graduate to types with electric trim so why not introduce them to the concept from the start?
I also wondered if the KI 300 standby EFIS would be better placed to the left of the PFD, with the starter, mags and ‘Batt/Alt’ switches relocated to where the standby EFIS is positioned, as this would reduce parallax. Finally, and as much as I like colour-coding, both the trim and flap position indicators are also colour-coded, which seemed a bit OTT to me.
Once the large canopy is shut, it is locked with a large handle that engages a well-designed claw mechanism with a pin in the windscreen bow. The latter doubles as a roll-over bar. The 914 starts smoothly (in fact, much more smoothly than the harsh, high-compression 912iS I regularly fly behind in glider tugs) and we set off behind the camera ship.
Taxying is easy?there’s a fine field of view over and either side of the nose as the seats are set quite high, the nosewheel steers through the rudder pedals and differential braking can be used to tighten the turn.
Ambient conditions are slightly above ISA (Fenland is essentially at sea level but the OAT is +18ºC) while the wind is a gentle zephyr from the east and the grass short and dry. We have about half-fuel, so as those 70 litres weigh about 50kg and we’re around 170 between us, we’re still some 70kg below the 750 MAUW, and the initial acceleration is good on the short, dry grass.
Then I remember the detent, raise the catch and push the lever fully forward. There’s a positive push as the turbo cuts in, and suddenly we’ve got an extra fifteen horses and the acceleration improves exponentially. The controls come alive almost immediately and the powerful rudder makes maintaining the centreline easy.
Having used about 400 metres of the grass runway the Sonaca skips into the sky and climbs away powerfully at about 750fpm and the Vy of 70kt. The limiting speed for T/O flap is usefully high at 105kt (some modern aircraft have ridiculously low flap limiting speeds) so there’s no rush to retract the flaps.
As they retract the change in pitch trim is quite subtle. Bring the throttle back past the detent and we set off in hot pursuit of the camera ship.
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A professional training tool?
An excellent question to pose at this juncture would be “would you buy a Sonaca for your ATO?” Assuming your students intend to obtain an EASA¬approved professional licence, they’ll need to train on an aircraft that EASA has approved for flight training.
Furthermore, as well as a CPL they’ll also need an IR, and preferably exposure to modern integrated avionics. One option is to buy a new C172, DA40 or PA¬28, while another is to completely refit a Skyhawk or Warrior with modern avionics.
The extra two seats of these alternative choices do add utility, but also greatly increase insurance premiums, while anything fitted with an avgas¬fuelled engine will cost a lot more to run.
Diesel engines burn much cheaper JET¬A1, but a brand¬new DA40 is a lot of money… and while the option of refitting a ‘legacy’ aircraft with a glass cockpit is definitely do¬able, do you really want a thirty¬year old machine representing your company?
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Once we’re over the coast the air is super-smooth and with the sunlight sparkling off the waters of The Wash I’m very much enjoying myself. Now, as much as I relish the challenge of flying close formation, to be honest I don’t always enjoy it.
Indeed, if the camera ship and subject aircraft are dissimilar types with very different performance it can be quite tricky. Throw in an aircraft with a poor field of view, limited power (or reduced drag), poor handling and some turbulence and a flight tester’s lot is not a happy one.
However, today is an absolute treat! Plenty of power, crisp controls and a fine field of view, along with air as smooth as glass make this a very pleasurable shoot.
Almost as soon as the wheels left the ground the 200 made a very positive impression, and when we break away from the camera ship to examine the control and stability, cruise performance, stall characteristics and everything else on the flight test card it continues to impress.
Stalls, power on or off and flaps up and down, are all equally benign, with little to no tendency to drop a wing. Clean and with the throttle at idle the wing quit at around fifty knots, while with full flap and some power the lowest indicated speed I saw was 42.
From the stability perspective, stick-free, the lateral and longitudinal stability are positive, and although directionally the 200 felt a bit ‘soft’, this is often the case where the nosewheel is linked to the rudder pedals.
As for control, it is very good, with light, crisp ailerons, a nicely-balanced elevator and powerful rudder (although in fact only a small amount of rudder is necessary to keep the slip ball centred, as there is little adverse yaw). Essentially, this is a stable aircraft with good controllability that is very nice to fly.
Cruising back towards Fenland at 3,000ft and a comfortable 5,000rpm gave an IAS of 100kt for a TAS of 106 and a fuel burn of 26-27 lph. Bumping the throttle up to the METO of 5,500 increases the IAS to 112 (twelve per cent), but the fuel flow goes up to about 34 lph, or an increase of roughly 25%. Pull the power back to a more relaxed 4,800 and it’ll still produce a TAS of 100 while only burning 23 lph. At this power setting the range is quoted as over 550nm, with a thirty-minute reserve. Pretty impressive.
It was such a lovely day I was reluctant to fly on instruments, but for the sake of completeness did get on the gauges for a few minutes. The large screen, well-defined horizon and synthetic vision would, I am sure, make it easy to fly in IMC. Indeed, the advent of the glass cockpit has made the entire instrument flying process very much easier than it used to be!
Back at Fenland what wind there was seemed to be favouring Rwy 08, but as we had the place to ourselves and Keith was on the ground near the threshold of Rwy 26, I elected to save him a walk and use that runway. I’d kept the speed up into the circuit and appreciated the faster-than-normal flap limiting speeds.
Even full flap is 85, while ‘Flap 2’ (20?) is a generous 95kt. About sixty over the fence felt about right. I did try one at 55, and wouldn’t recommend going much slower.
For the final touch ‘n’ go I deliberately left the flaps down and didn’t use full turbo power climbing out, and it still coped OK. This all left me very favourably impressed.
In the final analysis…
The Sonaca 200 is extremely well sorted and very nice to fly. And that’s a very important point as it is designed to be a trainer.
Other significant advantages which would appeal to a flight school are that it can be used for both basic and advanced training (it can be stalled and spun, or flown down an ILS with equal ease) and of course the engine typically burns around twenty litres of mogas an hour, making it considerably cheaper to run than many ‘legacy’ trainers.
Of course, it would also make an excellent tourer for the discerning (albeit well-heeled) private owner, so you may be wondering why there’s no autopilot fitted. The answer is simply because during the early stages of flight training the flight schools don’t want their students using an autopilot, and none has specified one as part of the equipment.
However?and particularly when touring?an autopilot can be very useful, if not essential, and Pierre assured me that one will be standard equipment on the IFR version currently under development.
What didn’t I like? Well, it is undeniable that the test aircraft is very expensive?in fact it is the most expensive Rotax-powered two seater I’ve ever flown?and I’ve flown quite a few! To be fair most (but not all) of those were kitplanes; this is a factory-built EASA VLA, and the panel is absolutely loaded (and note the the analogue version is around €31,000 cheaper).
There are going to be tens of thousands of young pilots aspiring to an EASA ATPL over the next twenty years, and they’ll have to train in an EASA-approved aeroplane.
Sonaca are pitching the 200 Trainer Pro firmly at that market, and to be honest, if I had just paid around €100,000 for a frozen EASA ATPL I think I’d expect to learn in something like this!
Image(s) provided by:
Keith Wilson
