Beechcraft Baron 58 (G58, IO-550-C)

The Baron 58 started in 1970 as a stretched version of the Baron 55. Beech added 10 inches to the fuselage, moved the rear door from the left side to a double-door layout on the right (large enough to load cargo or a stretcher), and revised the interior to seat six in a club seating arrangement. The original engines were Continental IO-520-Cs at 285 horsepower, the same as the late 55 variants. Two main production tracks ran in parallel for a decade and a half: the Baron 55 was discontinued in 1982 while the 58 kept going.

The IO-550 conversion arrived in 1984 with the Baron 58P (pressurized) and trickled into the normally-aspirated 58 by the mid-1990s. The current G58 has Continental IO-550-Cs producing 300 horsepower per side, with a 1,700-hour TBO (1,900 hours for engines built after serial number 1006000, per Continental Service Information Letter SIL 98-9E). The G58 designation arrived in 2005 with the Garmin G1000 panel as standard equipment. Garmin G1000 NXi replaced G1000 around 2014. The airframe is essentially unchanged from the 1984 IO-550 conversion.

Beech sold the Baron series to Raytheon in 1980, which sold it to Goldman Sachs in 2006, which sold it to Textron in 2014. Throughout, Baron production continued. The 58 family includes the pressurized 58P (1976-1985), the turbocharged 58TC (1976-1984), and the unpressurized normally-aspirated 58 that became the G58. The 58P and 58TC are out of production but parts remain available through Textron and the type-club network.

The Baron 58 cruises at about 200 KTAS at 75% power and 7,000 to 9,000 feet, burning 30 gph total (15 per side). Long-range cruise at 65% drops to about 180 KTAS on 25 gph total. Climb is impressive. The Baron will hold 1,500 fpm to about 6,000 feet at gross weight and still produce 700 to 900 fpm at 12,000 feet. Single-engine climb is the usual twin-piston conversation. The Baron 58 will hold roughly 270 fpm on one engine at sea level standard, which is meaningfully better than a Seneca V or a 310R at similar weight.

Useful load is the Baron's quiet advantage over the other piston twins. A typical G58 has about 1,800 pounds of useful load. Full fuel (190 gallons usable, 1,140 lbs) leaves about 660 pounds for people and bags. That's four adults and luggage, or six adults plus minimal bags. Cabin volume is bigger than any other piston twin in current production. Range with reserves is about 1,200 nm at 65% cruise.

The Continental IO-550-C is the standard engine on the G58 and on most 58s built since the mid-1990s. It's a six-cylinder, fuel-injected, direct-drive piston engine with a 1,700-hour TBO (1,900 hours for serial number 1006000 and later) per Continental Service Information Letter SIL 98-9E. It runs on 100LL. Field overhauls at Gann Aviation, Western Skyways, or other name-brand shops run about $52,000 to $65,000 per engine in 2026 prices. Multiply by two.

Earlier 58s used the Continental IO-520-C at 285 horsepower. The IO-520-C has a known light-crankcase history, with crank case cracks reported throughout the fleet. The IO-520-CB replaced it later in production and addressed many of the case issues. A pre-buy on a pre-1984 Baron 58 should always include a thorough case inspection. Owners who have the budget often choose to convert at overhaul time to an IO-550 via STC for the additional horsepower and the better TBO numbers.

Oil consumption on a healthy IO-550-C runs about 0.3 to 0.5 quarts per hour per engine, with mid-time engines on the higher end. Cylinder work at top-overhaul intervals (typically around 1,000 to 1,400 hours on hard-flown engines) runs $3,500 to $5,000 per cylinder, and the Baron has six on each side. A bad pre-buy can put a buyer into $30,000 of unscheduled cylinder work in the first year.

Plan on $400 to $600 per flight hour at 150 hours a year of utilization, all-in. The big variable buckets break down as fuel and oil ($175 to $215 per hour at 30 gph and $5.50 to $7 fuel), engine overhaul reserve ($60 to $80 per hour for two engines at $52,000 to $65,000 each over 1,700 to 1,900 hour TBO), prop reserve ($4 to $5 per hour for two props at $4,500 to $6,500 each over 2,400-hour TBO), and airframe maintenance reserve ($45 to $70 per hour). Annual fixed costs (hangar, insurance, annual inspection) add another $80 to $130 per hour at 150 hours a year of utilization.

The math is brutal at low utilization. Fly only 75 hours a year and your fixed-cost spread per hour pushes the all-in cost above $700. Annual inspection alone runs $5,000 to $12,000 depending on findings. Insurance is a meaningful number at any utilization. First-time twin owners with no multi-engine background can pay $12,000 to $25,000 a year. Established Baron 58 owners with 500-plus hours in type and Bonanza/Baron transition training pay $7,000 to $12,000.

Acquisition costs span a wide range. A 1970s Baron 58 with original IO-520-C engines, mid-time airframe, and steam-gauge avionics trades around $170,000 to $300,000. A 1990s IO-550 example with modern panel upgrades sits in the $400,000 to $700,000 range. A G58 with G1000 NXi and low hours runs $850,000 to $1.3 million. New G58s from Textron start above $1.7 million. The cleanest pre-G58 examples have been getting bought up by owner-pilots who don't want to wait the 12-18 months for a new G58 delivery slot.

American Bonanza Society membership is essential to operate this airplane economically. ABS technical support, type-specific transition training, and the member forum routinely save owners more in pre-buy avoided headaches than the annual dues cost over a 10-year ownership horizon.