Cessna 320 Skyknight

Overview

The Cessna 320 Skyknight is a six-seat, turbocharged piston twin that was Cessna’s mid-1960s answer to the question of how to get the 310’s airframe into the high teens and low flight levels. Produced from 1961 to 1969 across seven sub-variants (320, 320A, 320B, 320C, 320D Executive, 320E Executive, and 320F Executive Skyknight), it shared the 310’s wing, landing gear, and basic fuselage but added a swept dorsal fin, a lengthened nose, and most importantly two turbocharged Continental TSIO-470 engines of 260 hp each.

The Skyknight nameplate appeared on the 320B and was carried through to the 320F Executive Skyknight, widely regarded as the most refined variant. About 580 aircraft were built across all variants, a respectable run but well short of the 310’s 5,000-plus figure. The 320 was eventually replaced by the pressurised 340, which inherited the cabin-class ambition without the 320’s compromise of an unpressurised cockpit at flight-level altitudes.

For the buyer today the 320 is a niche aircraft. Its performance overlaps significantly with the 310’s, but the turbocharged engines make it more capable in the western United States and at high density altitudes. The trade-off is the maintenance cost of two turbo systems and the practical reality of needing oxygen for the upper end of the performance envelope.

Key Features for GA Buyers

• Turbocharged performance. Two Continental TSIO-470 engines deliver 260 hp each up to roughly 17,000 ft, where the 320F can reach a 225 KTAS cruise. Density-altitude performance is meaningfully better than a 310 of the same generation.
• Cabin and load. Six seats, useful load near 2,000 lbs, and the 310-derived fuselage give the 320 the same passenger and baggage capability as a 310 with added altitude flexibility.
• 310 commonality. Wing, landing gear, basic systems, and many spare parts are shared with the 310 line. A 310-experienced shop can support a 320 with limited additional type knowledge.
• Lower acquisition than a 340. The 320 sits at the bottom of the cabin-twin pricing band; for a buyer who wants altitude capability without the pressurisation premium, it is the cheapest path in.

Trade-offs

• Oxygen requirement. Without pressurisation, every flight at altitudes where the turbos are most efficient (12,000+ ft) requires supplemental oxygen for everyone on board.
• Turbo maintenance burden. Continental TSIO-470 turbo systems are mature but unforgiving of mismanagement. Cylinder cracking on the rear cylinders is a recurring issue, and turbo overhauls add a meaningful line item to operating cost.
• Slow for the power. Despite 520 hp installed, the 320’s cruise speed only marginally beats a non-turbocharged 310 at low altitude. The turbocharging is a high-altitude tool, not a sea-level speed advantage.
• Buyer pool. Sub-580-unit production and the 340’s overshadowing presence mean the resale market is thin. Sale times are typically longer than for a comparable 310, and the price premium over a similar-vintage 310 is modest.
• TSIO-470 parts availability. The TSIO-470 is no longer in current production; Continental and the field-overhaul market continue to support it, but lead times for hot-section parts can stretch.

See Also

• Cessna 310 – the unturbocharged, lighter sibling on the same airframe; the canonical version of this Cessna twin design. Compare
• Cessna 335 – the next-generation unpressurised cabin twin in the Cessna lineage; a meaningful step up in modernity at a higher acquisition cost. Compare
• Cessna 340 – the pressurised replacement for the 320; the segment Cessna eventually moved into. Compare
• Cessna 303 Crusader – Cessna’s last, much-later piston twin in the same six-seat segment; modern design with a fraction of the operating cost. Compare
• Beech Baron 55 – the most common cross-shop in the early-1960s six-place twin segment; lighter, faster, and dramatically more popular. Compare