Cessna 310

The Cessna 310 is an American six-seat, low-wing, twin-engined monoplane that was produced by Cessna between 1954 and 1980. It was the first twin-engined aircraft that Cessna put into production after World War II.

Development
The 310 first flew on January 3, 1953 with deliveries starting in late 1954. The sleek modern lines of the new twin were backed up by innovative features such as engine exhaust thrust augmenter tubes and the storage of all fuel in tip tanks in early models. In 1964, the engine exhaust was changed to flow under the wing instead of the augmenter tubes, which were considered to be noisy.

Typical of Cessna model naming conventions, a letter was added after the model number to identify changes to the original design over the years. The first significant upgrade to the 310 series was the 310C in 1959, which introduced more powerful 260 hp Continental IO-470-D engines. In 1960 the 310D featured swept back vertical tail surfaces. An extra cabin window was added with the 310F.

The 320 Skyknight was developed from the 310F, which featured turbocharged TSIO-470-B engines and a fourth cabin side-window. The Skyknight was in production between 1961 and 1969 (the 320E was named the Executive Skyknight), when it was replaced by the similar Turbo 310.

The 310G was certified in 1961 and introduced the canted wingtip fuel tanks found on the majority of the Cessna twin-engine product line, marketed as 'stabila-tip' tanks by Cessna because they were meant to aid stability in flight. A single side window replaced the rear two windows on the 310K (certified in late 1965), with optional three-blade propellers being introduced as well. Subsequent developments included the 310Q and turbocharged T310Q with redesigned rear cabin featuring a skylight window, and the final 310R and T310R, identifiable by a lengthened nose containing a baggage compartment. Production ended in 1980.

Over the years there were several modifications to the 310 to improve performance. Noted aircraft engineer Jack Riley produced two variants, The Riley Rocket 310 and the Riley Turbostream 310. Riley replaced the standard Continental 310 hp engines with Lycoming TIO-540 350 hp engines. These turbo-charged intercooled engines were installed with three-blade Hartzell propellers in a counter-rotating configuration to further increase performance and single engine safety. At 5400 lb. gross weight the aircraft had a weight to power ratio of 7.71 lb. per horsepower. This resulted in a cruising speed of 260 kn at 18000 ft and a 3,000fpm rate of climb.

Commercial applications
The Cessna 310 was a common charter aircraft for the many air taxi firms that sprang up in the general aviation boom that followed World War II. The advantages of the Cessna 310 over its contemporaries, such as the Piper PA-23, were its speed, operating costs and after market modifications such as the Robertson STOL kits which made it popular world wide for its bush flying characteristics. It could use short runways while at the same time carrying a large useful load of 2000 lb. or more, at high speeds for a twin engine piston aircraft.

Military applications
In 1957, the United States Air Force (USAF) selected the Cessna 310 for service as a light utility aircraft for transport and administrative support. The USAF purchased 160 unmodified 310A aircraft with the designation L-27A and unofficially nicknamed Blue Canoe, later changed to U-3A in 1962. An additional 36 upgraded 310 designated L-27B (later U-3B) were delivered in 1960-61; these aircraft were essentially military 310Fs and as such equipped with the more powerful 260 hp engines and can be identified by their extra cabin windows, longer nose and swept vertical fin. A USAF study after one year of operational service found the U-3A had direct operating costs of less than $12 an hour. Some USAF aircraft were later transferred to the US Army and US Navy and the type continued in US military service into the mid 1970s.

Variants

 * 310:Production aircraft powered by two 240 hp Continental O-470-B engines, 547 built.
 * 310A:Military version of the 310 for the United States Air Force, designated L-27A and later U-3A, 160 built.
 * 310B:310 with new instrument panel, O-470-M engines and minor changes, 225 built.
 * 310C:310B with 260 hp IO-470-D engines, increased take-off weight and minor changes, 259 built. Unit cost $59,950 in 1959
 * 310D:310C with swept vertical tail and minor detail changes, 268 built.
 * 310E:Military version of the 310F, designated the L-27B and later U-3B, 36 built.
 * 310F:310D with extra cabin window each side, pointed nose, new tip tank shape and other minor changes, 156 built.
 * 310G:310F with slimline tip tanks, six-seat cabin, an increased take-off weight and detail changes, 156 built.
 * 310H:310G with increased take-off weight and enlarged cabin interior, 148 built.
 * 310I:310H with IO-470-U engines, baggage compartments in rear of engine nacelles and minor detail changes, 200 built.
 * 310J:310I with minor detailed changes, 200 built.
 * 310K:310J with long 'vista view' side windows, increased take-off weight and IO-470-V engines, 245 built.
 * 310L:310K with single-piece windshield, re-designed undercarriage, increased fuel capacity and minor changes, 207 built.
 * 310M:Revised designation for the 310E.
 * 310N:310L with revised instrument panel, optional fuel tanks in engine nacelles, IO-470-V-O engines and minor changes, 198 built.
 * 310P:310N with a shorter nose undercarriage leg, ventral fin, and optional turbocharged Continental TSIO-520-B engines, 240 built.
 * 310P with take-off weight increased to 5300 lb and detailed changes, from the 401st aircraft fitted with a bulged rear cabin roof with rear view window, 1160 built.
 * 310R:310Q with three-bladed propellers, lengthened nose with baggage compartment, 5500 lb take-off weight and 285 hp IO-520-M engines, 1332 built.
 * 310S:Original designation for the Cessna 320.
 * 320 Skyknight:Enlarged version of the 310F with six seats, larger cabin and two turbocharged engines, 110 built.
 * 320A Skyknight:320 with stabil-tip fuel tanks and minor changes, 47 built.
 * 320B Skyknight:320A with nacelle baggage lockers and minor changes, 62 built.
 * 320C Skyknight:320B with a longer cabin, optional seventh seat and minor changes, 73 built.
 * 320D Executive Skyknight:320C with reshaped rear windows and 285 hp TSIO-520-B engines, 130 built.
 * 320E Executive Skyknight:320D with pointed nose, single piece windshield, modified undercarriage, increased take-off weight and minor changes, 110 built.
 * 320F Executive Skyknight:320E with minor changes, 45 built.
 * L-27A:United States military designation for the 310A, later changed to U-3A.
 * L-27B:United States military designation for the 310E/310M, later changed to U-3B.
 * U-3A:L-27A redesignated in 1963.
 * U-3B:L-27B redesignated in 1963.
 * Riley 65
 * Cessna 310 to 310G by fitting two 240-260 hp (179–194 kW) Continental O-470D/-470M engines.


 * Riley Super 310
 * Conversion of Cessna 310/320 by fitting two 310 hp (231 kW) Continental TSIO-520-J/-N engines.


 * Riley Rocket
 * Conversion of Cessna 310 by fitting two 290 hp (216 kW) Lycoming IO-540-A1A5 engines and more fuel.

Civil
The aircraft is popular with air charter companies and small feeder airlines, and is operated by private individuals and companies.

Military operators
Countries known to have operated the U-3/310 include.
 * Cessna 310 and 320 models
 * French Air Force - 12 operated
 * Armed Forces of Haiti
 * 🇮🇩 Indonesia
 * Indonesian Air Force
 * Indonesian Army Aviation
 * 🇲🇬 Madagascar
 * Malagasy Air Force - One 310R
 * Mexican Naval Aviation
 * 🇵🇪 Peru
 * Peruvian Naval Air Service
 * 🇵🇭 Philippines
 * Philippine Air Force
 * 🇹🇿 Tanzania
 * Tanzanian Air Force
 * United States Air Force received 196 L-27A and L-27B (later redesignated U-3A and B).
 * United States Army received 25 ex-US Air Force L-27As (later U-3As) and at least 13 L-27Bs (later U-3B) from 1960.
 * 🇺🇾 Uruguay
 * Uruguayan Air Force (One 310R)
 * Venezuelan Naval Aviation
 * Zaire
 * Zaire Air Force
 * Tanzanian Air Force
 * United States Air Force received 196 L-27A and L-27B (later redesignated U-3A and B).
 * United States Army received 25 ex-US Air Force L-27As (later U-3As) and at least 13 L-27Bs (later U-3B) from 1960.
 * 🇺🇾 Uruguay
 * Uruguayan Air Force (One 310R)
 * Venezuelan Naval Aviation
 * Zaire
 * Zaire Air Force
 * Zaire
 * Zaire Air Force

Accidents and incidents

 * On October 28, 1959, a Cessna 310 carrying Cuban revolutionary Camilo Cienfuegos disappeared over the Atlantic Ocean on a night flight from Camaguey to Havana. Neither the aircraft nor the body of Cienfuegos were ever found.


 * On November 26, 1962, a VASP Saab Scandia 90A-1 registration PP-SRA en route from São Paulo-Congonhas to Rio de Janeiro-Santos Dumont collided in the air over the Municipality of Paraibuna, State of São Paulo with a private Cessna 310 registration PT-BRQ en route from Rio de Janeiro-Santos Dumont to São Paulo-Campo de Marte. Both were flying on the same airway in opposite directions and failed to have visual contact. The two aircraft crashed killing all 23 passengers and crew of the Saab and the four occupants of the Cessna.


 * On July 19, 1967, a Boeing 727 operating as Piedmont Airlines Flight 22 collided with a Cessna 310 at Hendersonville, North Carolina, USA, killing all 79 people on board both aircraft and three people on the ground.


 * On October 16, 1972, U.S. Congressmen Nick Begich of Alaska, and Hale Boggs of Louisiana, disappeared over Alaska while flying in a Cessna 310 during a campaign trip.


 * On 19 December 1992, Cuban defector Major Orestes Lorenzo Pérez returned to Cuba in a 1961 Cessna 310 to retrieve his wife Vicky and his two sons. Flying without lights, at low speed and very low altitude to avoid Cuban radar, Pérez picked up his family by landing on the coastal highway of Varadero beach, Matanzas Province, 93 mi west of Havana and managed a successful safe return to Marathon, Florida.


 * , the NTSB has recorded 1712 incidents for Cessna 310s since 12 January 1964.