Overview

The Rockwell Commander 690B is the matured form of the Commander 690 turboprop series, produced from 1976 to 1979 and certified under FAA TCDS 2A4. It is a pressurised, high-wing, twin-turboprop cabin-class aircraft powered by two Honeywell (originally Garrett AiResearch) TPE-331-5-251K engines, each rated at roughly 717 shaft horsepower and driving three-blade Hartzell propellers. About 217 airframes were built.

The 690 family traces directly back to the piston Aero Commander 680 line: when Aero Commander engineers shopped for more performance than the IGSO-540 supercharged piston engine could give, the choice was the then-new Garrett TPE-331 single-shaft turboprop. The 690 added a fully pressurised cabin, a redesigned wing with the engines moved further outboard, and modern turbine reliability to an airframe whose stout high-wing layout was already a known quantity in U.S. business and utility flying. The 690B refined that recipe with a higher MTOW (10,325 lb), better soundproofing, an internal lavatory, and minor systems updates.

For a buyer evaluating one today, the 690B sits in a narrow band of the used-turboprop market: about 279 KTAS cruise, a 31,000 ft service ceiling, and a 10,325 lb MTOW give it genuine cabin-class turbine capability in a high-wing airframe. The high wing buys ground clearance, easy cabin access, and unobstructed views from passenger seats, but the airplane is unambiguously a serious turbine that wants two crew and a Type Rating-grade approach to systems management.

Fleet support is the single most important contextual fact. Twin Commander Aircraft LLC (the type-club and TCDS holder) actively maintains the type with the Service Center network, mandatory inspection guidance, and the long-running Grand Renaissance airframe refurbishment program. A 690B that has been kept current at a Twin Commander Service Center is meaningfully more operable than one that has not.

Key Features for GA Buyers

• Turbine reliability with serious cabin. Pressurised to 5.2 psi for a sea-level cabin to roughly 12,000 ft, a 31,000 ft service ceiling, and twin Garrett TPE-331-5s with a 5,400-hour TBO under current Honeywell SOAP/CAM programs. Real all-weather, IFR-without-asterisks transport.
• Cruise that earns the fuel burn. Normal cruise of about 279 KTAS at FL200 and up to 284 KTAS at lower altitudes, with a 1,419 NM long-range cruise range at 45-minute reserve.
• High-wing utility. Long, unobstructed cabin entry; props well clear of the ground for unimproved-field operations; passenger sightlines that piston-twin and Beech-cabin buyers immediately notice. Useful load of about 4,180 lb leaves room for full fuel plus six adults and bags.
• Type-club support is real. Twin Commander Aircraft LLC maintains an active Service Center network, factory-supported continued airworthiness program, and the Grand Renaissance refurbishment line. Type-specific recurrent training is widely available; this is not a given on a 1970s turboprop.
• Strong short-field numbers for the weight class. About 2,259 ft takeoff and 2,084 ft landing over a 50 ft obstacle at sea level, with an initial climb rate near 2,849 fpm at MTOW. The Commander gets in and out of airfields that nominally belong to lighter airplanes.

Trade-offs

• TPE-331 hot-section economics. The -5-251K is a single-shaft engine with a well-documented but expensive maintenance profile: hot-section inspection roughly every 1,800 hours, full overhaul at 5,400, and labor-intensive negative-torque-system and fuel-control attention. Budget for engine reserves accordingly; this is not a Pratt PT6 in cost behavior.
• Single-shaft start and handling discipline. TPE-331 starts require deliberate technique; mismanaged starts are a known way to ruin a hot section in seconds. Type-specific training is non-negotiable for a new-to-type owner.
• Cabin is comfortable, not large. Typical executive seating is 2 crew plus 5 passengers (the certification allows up to 10 in a commuter layout, but that is rare in surviving airframes). Cabin height about 4 ft 5 in, adequate, not stand-up.
• Aging avionics in many airframes. Many 690Bs still fly with 1970s panels unless they have been through a major upgrade or the Renaissance program. Plan on $150k-$400k for a modern Garmin or Collins panel if the airplane has not had one.
• Fuel burn at altitude. Roughly 70-90 gph combined in cruise depending on power setting and altitude. The -5 engines are less efficient than the later -10 dash that flies on the 690C/D and 695-series; if mission economics matter, the -10 conversions sold by Twin Commander Service Centers are worth pricing.
• Parts and AD currency. The TCDS is mature and the type has a long AD history (wing spar, flight-control attach hardware, and others). A pre-buy at a Twin Commander Service Center, not a generalist shop, is the only sensible approach.

See Also

• Aero Commander 680FL – Piston-Commander predecessor; the high-wing IGSO-540 piston twin that the 690 turboprop grew out of. Compare
• Gulfstream Jetprop Commander 1000 – Stretched, re-engined successor; the 695A with TPE-331-10s and a longer cabin is the natural step-up for buyers who need more. Compare
• Mitsubishi MU-2B-60 Marquise – Direct era competitor; the other 1970s pressurised cabin-class twin on TPE-331 power, with a very different handling reputation. Compare
• Beechcraft King Air 90 – Direct era competitor; the canonical PT6-powered alternative at similar size and cabin: Garrett vs Pratt economics in one comparison. Compare
• Piper Cheyenne II – Direct era competitor; PT6A-28-powered low-wing alternative at similar mission and seat count. Compare