by Rick Durden
Airplane makers have a rich tradition of trying to balance the demands of building a load-hauling piston single without the result looking like the design engineer had been badly frightened by a steamer trunk during his youth.
Despite fervent wishes of aerodynamicists, no one has devised a better or cheaper shape for lugging lots of stuff than a box, even though Cessna managed to taper that shape somewhat with its 185, 206 and 207.
Now, from Australia, comes a hauler that makes no bones about being a box and may give the Cessna 206 competition at airports where the only question is how much can be stuffed into an airplane.
The Australians have lots of rough country. So its no surprise that an established Australian manufacturer of workhorse agricultural airplanes, Gippsland Aeronautics, should turn its attention to those who carry people and things where theres neither rail nor road.
Gippsland Aeronautics is at the Latrobe Regional Airport in Morwell, Australia. Telephone from the U.S. is 011 61 3 5172 1200; it can be found on the Web at www.gippsaero.com. The company has been around since the mid-1980s, having started with a single-engine Ag airplane. The eight-place GA8 Airvan is priced at under $325,000, making it competitive with Cessnas normally aspirated 206.
This Aint Pretty
Its almost a clich that the best utility airplanes are ugly and the Airvan is true to the rule. For some reason, it doesnt photograph well; in person, its not unattractive. We arent being negative; as it appears Gippsland engineers did their aerodynamic box homework well.
With 275 HP, less power than a Cessna 206 or 207, the Airvan carries more, has a roomier cabin and is only about 20 percent slower, although for a trip of any length, that 20 percent is significant. The GA8 is currently certified for VFR operations under FAR Part 23 through Amendment 48 in the U.S., Australia, New Zealand, South Africa and Indonesia with certification expected in the UK and Canada soon. IFR certification was to occur by June 2002 but has evidently been delayed.
As of this writing, about 15 have been delivered and Gippsland says it has orders for at least 25 more. A price of $325,000 includes an IFR package with avionics by Honeywell/Bendix/King, notably the KMD150 color multifunction display. Autopilot certification is in the works. The airplane flown for our review was serial number 8 and had only recently been put into service by Maya Island Airlines for its operations in Belize, where we were visiting last winter. Maya also has Cessna 207s, 208s and Britten-Norman Islanders.
At the time of our flight, the airplane hadnt accumulated 100 hours in service but, according to Maya pilots, was generally doing well in a harsh environment. The exception was a high level of prop blade erosion near the tip.
The airplane is extensively corrosion proofed, although one oversight was that many of the small fasteners had already rusted. Weve been told that Gippsland is responsive to field experience so we trust it will switch to stainless steel fasteners soon.
There are doors for each front seat, something float operators demand.The doors open all the way forward to latch against the cowling so a person can walk along a float. The left side of the airplane has a 42.5-inch by 42-inch sliding door and steps that fold out for passenger loading.
The doorsill is angled so that a forklift can drive straight up to the door and heavy freight can be slipped aboard without having to bridge a gap.The cabin is unusually wide for an airplane of this size, allowing 55-gallon drums to be loaded side by side or, in passenger configuration, it provides a surprisingly wide aisle between seats. The cabin floor is flat, an attractive feature to any pilot who has hauled cargo in little airplanes.
The passenger seats, while not adjustable fore and aft, snap in and out quickly using a small, curved tool that looks like something that will get lost easily unless it has a dedicated spot to be stowed. The attach points for the seats double as freight tie-downs.
The passenger seating position is quite upright and legroom was tight. But comfort was quite adequate for an hours flight. Seating is four rows of two seats, beside large windows, giving excellent visibility for all aboard.
We were told the seats are the only general aviation seats certified to the latest version of the FARs for impact loading (26 Gs) and thus will stroke downward, absorbing impact. The main gear is similar to the tubular design that has worked so well on the Cessna 207. The nose strut is a spring/oil arrangement, akin to the successful set-up on the Cessna 208 Caravan and it has no damper to break.
Maintenance folk at Maya complained about damper wear on the Cessnas but in the same breath, they were critical of the Airvans turning radius, which is too large. Gippsland told us at Oshkosh that the turning radius has been radically reduced by a redesign of the nose gear and that a retrofit kit was provided to Maya Island Air.
The 40-foot-8-inch constant chord wing has an 8-to-1 aspect ratio and a flat underside, consistent with a desire for load carrying ability at lower speeds rather than cruise performance. The ailerons and manual flaps are externally hinged and the flaps are straight flaps, not Fowler. They still reduce stall speed from 60 to 52 KIAS, with the 14-degree notch used for takeoff and 38 degrees for landing.
The cowling is carbon fiber, so its expected to be easy to repair. Large portions of each side of the cowling are attached with quick-release fasteners allowing relatively rapid access to the engine room, without having to take off the entire cowling.
As noted, the prop showed more erosion wear and dings than we would expect for fewer than 100 hours and Maya engineers (Brit for A&P) said they were watching this. Further, they felt it was more related to the wide turning radius and the extra power pilots had to use to turn in tight areas. The turn radius kit might address this.
The horizontal tail is both thick and long, having a span of 13-feet, 7 inches and offering a clue as to how this airplane can have a CG range long enough to accommodate four rows of seats and a baggage compartment that reaches into the empennage. The entire stabilizer moves for pitch trim.Several pilots told us that its wise to set the pitch trim correctly for takeoff based on cabin load distribution because an out-of trim-takeoff is a high workload item requiring some muscle. In the airplane we flew, our trial was complicated by a pitch trim wheel that was so stiff that it took two hands to adjust the trim. We learned that this was due to a lack of lubrication and later observed that on another Airvan, the trim wheel could be rolled with a fingertip.
Ingress, Loading, Systems
Getting into the airplane requires that the pilots do a little climbing, making use of an external step and a grab handle, for the floor is 33 inches above the ground. The main gear is far enough aft that the Airvan doesnt have a tendency to sit on its tail if the aft pax or baggage is loaded first. The tradeoff of this gear position is that it takes a positive tug to lift the nose for takeoff, especially with a forward CG limit.
Head and legroom for all sizes of pilots is adequate. The appointments are utilitarian, but not Spartan. For a true utility airplane, its surprisingly comfortable and attractive inside. Each passenger seat has an integral seatbelt and shoulder harness, something we applaud for crashworthiness. The pilots get five point restraints, a good thing in our opinion, as theres little flail room available on impact and there are a number of sharp edges on the flight deck that we believe should be addressed.
Unfortunately, the Airvan has a ceiling switch panel, something weve been consistently critical of. Overheads have all sorts of protrusions that can dent the skull in a crash and even in normal ops, the switches are difficult to read for the bifocal set. Wed like to see Gippsland find another place for the circuit breakers and switches.
The instrument panel itself is well designed, in tasteful gray metal. The airplane is obviously designed for a pilot whos going to work long hours, so gauges are canted toward the pilot. Everything is easily in reach and the seat, especially when covered with the optional sheepskin cover, is comfortable and cool.
The power controls are on a pedestal that protrudes aft so that everything falls comfortably to hand. While we feel that control wheels should go the way of the dinosaur, the ones on the Airvan are small enough and curved so that the legs of a large pilot wont interfere much with movement.
The Airvans powerplant is a Lycoming IO-540-K1A5, developing a continuous 275 HP at 2500 RPM. The airplane was certified at that power setting for the increasingly stringent international noise requirements.
However, theres a gate arrangement for the prop control allowing the pilot to command 2700 RPM to obtain 300 HP, although the setting is labeled emergency.
We expect operators will demand that Gippsland find a way to get the full 300 HP from the engine, particularly if weight is boosted by the rumored 200 pounds.
The fuel system is a tribute to engineering creativity in responding to the tough new certification requirements. Crash data makes it clear that when pilots dont have to select fuel tanks, the fuel-related accident rate drops significantly. As a result, certification now essentially requires an on/off system, yet the regs prohibit a fuel-injected engine from drawing fuel from more than one tank at once.
Gippsland created a system where the fuel goes from each wing tank to float valves in the forward fuselage that regulate the flow to keep the tank quantities about equal, then into a sump tank from which the engine draws fuel. Thus the engine only pulls fuel from one tank and a fuel shutoff downstream of the sump tank is the only pilot-operated valve in the system.In addition to the standard fuel gauges, low fuel levels in the wing and sump tanks are annunciated.
The electrical system is powered by a 95-amp alternator, but is 12 volt, so the airplane can be jump-started from a car. We were a little surprised at the 12-volt decision as a 24-volt system is usually more durable in commercial operations. The system has two busses, with one powering essential equipment such as the GPS, one comm and the instrument and landing lights.
Weight and Payload
Gross weight of the Airvan is 4000 pounds. The empty weight of the tested airplane was 2291 pounds, giving a useful load of 1708 pounds, 137 pounds more than the Cessna U206F we used for comparison. Usable fuel is 87.3 gallons or 523 pounds, versus 76 gallons and 456 pounds for the 206.
Neither the Airvan nor the U206F has a zero-fuel weight limit. With full fuel, 1184 pounds can be carried in the cabin of the Airvan and 1115 pounds in the 206. (Keep in mind that the Airvan has 25 fewer horsepower than the 206.)
As one person put it, full fuel in an Airvan easily allows for a hungry pilot and five hefty Americans. The center of gravity range is 16 inches at light weights, tapering to 8 inches at gross weight, nearly identical to a 206, long known for having a flexible CG range.
Its possible to load the Airvan out of the aft limit, particularly because the baggage compartment goes so far into the tail. But it would take an effort; the airplane doesnt have an aft-tending center of gravity. Maya pilots told us that the airplane tends to hunt in pitch when loaded to the aft limit. They also said the airplane is about 5 to 8 knots faster in cruise when loaded toward aft CG.
Captain Nigel Carter, whose experience includes the Cessna 206, 207 and 208 in commercial ops, introduced us to the airplane. According to Carter, the Airvan carried more and handled better than the Cessnas and was thus a better all-around airplane for hauling people and baggage, even though it was noticeably slower. He noted that passengers liked the Airvan better than the 206 and 207 because it had more room, sat level and was easier to enter and exit.
Hot starting the Lycoming proved to be a challenge in the heat of Belize, requiring a deft combination of mixture, throttle and aux pump. Taxiing the airplane was comparable to the Cherokee 235, with a positive link to the nosewheel and some heaviness to let the pilot know theres a big engine up front.
The Airvan took more runway than a Cessna 206 might but it tracked straight without much work, something vital on the runways in Belize. At about 60 knots, a gentle tug raised the nose to get it airborne.
Once in the air, the first impression is of astonishing visibility. The nose is low during the climb and the pilot sits ahead of the wing, so theres no loss of visibility in a turn. The pilot-side windows go down to waist level and the sill provides an armrest. Those windows are also bulged slightly, so the pilots can look straight down. The portion of the windshield thats curved sharply down and aft had noticeable distortion, but it didnt cause problems in the maneuvers we conducted.
The cabin windows seem huge, so everyone gets a good view. We anticipate this airplane will be quite successful in the sightseeing business and, with the sliding rear door, for aerial photography and skydiving. Each passenger seat has an overhead air vent, but in the heat of Belize, the system was barely adequate. A vent system that delivers a larger volume of air would be nice. At about 90 KIAS, on an 80-degree day and a weight of 3250 pounds, we initially climbed at 700 FPM. That dropped to slightly below 500 FPM by 6000 feet. The airplane needs every bit of its rated power, so theres no reduction to climb power after takeoff. In cruise, the Airvan is stable and comfortable, but most assuredly not fast. Still, Maya pilots said the airplane consistently beat book speeds, particularly if light or loaded toward the aft CG limit. At 6500 feet, we indicated 115 knots at 23 inches and 2500 RPM, which was full throttle and max RPM. That worked out to 129 knots true, well above book speeds at 75 percent power. By comparison, look for about 145 knots in a U206F.
Gippsland is working with Lycoming to install sophisticated fuel and ignition control and monitoring systems to reduce fuel flow and increase range. In the mean time, we believe it would behoove buyers to make an engine analyzer and GAMIjectors standard so that fuel flows could be cut by 2 or 3 GPH. Given the low cost and benefits, an engine analyzer should be standard equipment in every new aircraft, in our view.
For a van, the Airvan handles more like a lighter airplane. Once trimmed, few changes are needed. The airplane is lighter in all axes than the Cessna 206, especially in pitch and is no comparison at all to GAs air barge, the Cherokee 6.
An attempt to stall the Airvan, power off, at a forward CG resulted in getting the yoke full aft without further progression of the stall; the sink rate merely increased. The airplane flew out of it with full power and progressive flap retraction, although the amount of power available meant that it took longer to arrest the sink rate than we expected. We observed no pitch change with flap extension or retraction.
Final approach is flown at about 70 knots. Any extra speed will cause the airplane to float. As with the 206, the airplane behaves much differently when loaded than when light. The nose-low sight picture on final is similar to the Cessna Caravan.
The nose also tapers from the sides toward the prop, so a new pilot needs to determine whats actually straight ahead to avoid side loading the gear on touchdown. Even with a forward CG, the effort to raise the nose for a full stall landing is much less than a similarly loaded 206. Max demonstrated crosswind component in the airplane is only 15 knots, and we did hear some complaints about the effectiveness of the odd-looking, half-span rudder.
With the almost paranoid certification requirements for spins, rudder effectiveness becomes a victim, so Gippsland engineers had their hands full complying with spin resistance requirements while assuring adequate rudder authority for crosswinds. If this airplane proves to have an Achilles heel for backcountry work, the rudder may be it.
Because avgas is difficult to get in many parts of the world, Gippsland is developing a turboprop version of the Airvan, but wrestling with the less-than-stellar specific fuel burns involved. Theyre leaning toward an Allison 250-series engine because of its better fuel specifics over the PT6.Gippsland is also working with a European manufacturer on what may be a better alternative, a 310 HP diesel.
While field experience will tell if the Airvan is tough enough, the basic airplane impressed us. Of some concern is the prop erosion issue but we liked the size of the cabin and passenger amenities in an airplane of this size and its load carrying capability is a plus.
Well follow up in a year or two to see how well the airplane is being received in the U.S. It appears to fill a niche and represents a realistic alternative to the Cessna 206.
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Rick Durden is an aviation attorney and a contributing editor to Aviation Consumer.