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Business Aviation & Piston Twins
Capability- redundancy and complexity.

An uncanny number of businesses (numbering into the thousands) operate business aircraft of a dizzying variety. These top out at the Businessliners (adapted airliner models)- and move down through the size and weight categories all the way to the (typically owner-flown) piston aircraft.

A single-engine piston aircraft suffices for thousands of small companies and individually- owned businesses- allowing them to do all the things that make a business aircraft advantageous- including:

• Reaching communities inconvenient or impossible to reach via the airlines;
• Reduce travel times;
• Deliver necessary goods or expertise;
• Support remote operations (and much- much more).

For many businesses- a piston twin-engine aircraft offers not only greater redundancy- but also higher capability and utility over the piston-single. Every business starts somewhere- with that initial airplane that meets its initial needs. Often- however- experience shows that business more ways to use the airplane- and those changes sometimes call for a change from that first airplane.

The business that started with a single piston aircraft may find that the natural next step is into a twin. As with any choice- the piston twins come with their own pros and cons- some of which we’ll consider below.

BENEFITS WITH LIMITS
Among the benefits offered by piston twins we find the obvious and the subtle. The addition of a second engine enhances most airplanes’ payload and speed. Beyond a higher cruise speed- however- the added horsepower of a second engine can also enhance take-off and climb performance- equating to shorter runways and quicker climbs.

For trips up to 350 nautical miles a fast-flying piston twin gives up only minutes to a jet in trip time - and even up to 500 miles the piston-twin arrives within 30-35 minutes- costing a fraction of the price of a jet (and often less than an airline ticket).

In fact- some piston twins can deliver four passengers at costs equitable to driving that trip. Those traits are all attractive. A second engine provides a measure of redundancy too – but it’s redundancy with limits… The piston twin- in general- cannot complete a take-off after an engine failure- cannot maneuver very nimbly- or- in general- cannot climb – and if it can- only in a narrow speed range.

Most piston twins employ engines that rotate in the same direction (a cost-saving approach since left and right-side systems are identical). But this approach brings with it a drawback should one engine fail: the existence of a “critical engine.” When both engines spin in the same direction engine forces of both want to pull the airplane to the left. If you lose that ‘critical engine’ on the left and the airplane wants to turn into the dead engine with huge leverage- the potential exists to invert the airplane as it resists being turned right. If the non-critical engine fails- the pilot still faces challenges – but less severe.

The key is observing the correct speeds and attitudes proscribed by the OEM- which can vary depending on which engine fails. Some piston-twins employ counter-rotating engines mounted so that neither becomes a critical engine during a failure- resulting in identical failure responses should either side fail (which is a rarity).

OTHER LIMITATIONS ON REDUNDANCY
Twin-engines - whether piston- turboprop or jet - demand a higher degree of knowledge and preparation- simply because such aircraft generally employ more complex systems to match their higher level of capability. Any aircraft type demands intimate familiarity- practice and preparation to use to its highest level of utility and safety. Simply stated- moving to twins from singles means moving into a more-complex machine.

A pump needed to flex de-icing boots may exist only on one engine; ditto for an engine-driven alternator or pressurization system. Adding pressurization- alone- raises both the capability and complexity of the airplane. In fact- training and competency increase in importance as the performance and complexity of the machine grows.

THE AFFORDABLE HIGH-PERFORMANCE OPTION
Today- manufacturers offer only four business- capable piston twin options: Diamond Aircraft’s (four-seat) DA42 TwinStar; Hawker Beechcraft’s G58 Baron and Piper’s Seneca V (both six-seat); and Piper’s Seminole (four-seat). A new Baron fetches upwards of $1.1 million; the Seneca V about $700-000; the Seminole well under a half-million-dollars; and the Diamond DA42 TwinStar about a half-million - depending on whether the operator opts for two Lycoming 180-horsepower engines or Austro Engines AE300 turbo-diesels. Further- excellent examples of these and other piston twins can be found on the pre-owned market at prices well below $300-000- many with modern avionics panels and low-time engines.

As regards the costs to operate these aircraft- as an example- the Baron costs approximately $1.75 per mile to fly – or about $360 an hour flying about 400 hours per year. The Seneca V (utilizing smaller engines with about one-third the fuel consumption of the Baron- and turbo-charging to allow higher flight and higher average speeds - along with lower hull-insurance due to a lower ‘as-new’ price) offers an hourly operating figure of approximately $265 an hour. The Diamond TwinStar- meanwhile- offers the lowest fuel consumption of the batch- managing 175 knots at a total fuel consumption of about 12 gallons per hour at 14-000 msl.

At the other end of the scale are a number of attractive- popular piston twins with pressurized cabins – in particular Cessna’s out-of-production 340- 414 and 421 models. Their operating costs may run higher than the Baron’s- but their low purchase prices- high speed and large cabins help keep them in high demand and dear to the company accountant’s heart. Following is a selected listing of piston twin models popular with business users- along with their current market value as listed by Vref (www.vrefpub.com).


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