Development the Yak-40 as a replacement of the ageing LI-2, Il-12 and Il-14's, started in 1965 by the Yakolev Design Bureau. The Yak-40 was required to operate from Class 5 grass airfields or semi-prepared strips. The resulting aircraft has high-lift lightly-loaded wings and, for added safety, three Ivchenko AI-25 turbojets. All three engines are operated on take-off, but the central engine may be throttled back to idle for fuel economy during cruise. In configuration, the Yak-40 is a cantilever low-wing monoplane with retractable tricycle landing gear, rear-mounted engines and with accommodation for a flight crew of two or three and up to 32 passengers. The provision of a ventral rear door with airstair makes it possible to operate the Yak-40 from airfields with minimum facilities, and an onboard auxiliary power unit makes the type independent of ground equipment for engine starting and the maintenance of cabin heating and air-conditioning.
The first prototype tri-jet was flown on 21 October 1966, the Yak bureau eventually building five pre-production test airframes. The type entering revenue service with Aeroflot on 30 September 1968 with 2 crew and 27-31 passengers (NATO reporting name 'Codling').
The Yak-40 is cleared for Class Five grass airfield operations, and to improve its short landing performance a single clamshell thrust reverser has been fitted to the centre engine on later production models. The rear-mounted turbofan engines enable it to take off and land within 1500 ft (500 m), and it can operate from grass fields.
The Yak-40K cargo version is configured purely for the carriage of freight, the aircraft being cleared to carry a load of up to 5070 lbs in weight.
When production ended in 1980, 1011 Yak-40 airliners were built in Saratov in the former USSR. The majority of these are still in service in 1993, with both military and civilian operators.
Engines, Ivehenko Al-25 (3 x 3300 lb thrust)
Max take-off weight, 27,500 lb
Payload. 5500 1h
Cruising speed, 405 kt
Range. 620-1240 st. miles
Take-off distance to 50 ft, 1950 ft
No. of passengers, 24
Engines: 3 x 3,306 lb (1,500 kg) st Ivehenko AI-25 turbofans
Wing span: 82 ft 0.25 in (25.00 m)
Length: 66 ft 9.5 in (20.36 m)
Wing area: 735 sq ft (70.0sq.m)
Gross weight: 30,200 lb (13,700 kg)
Max cruising speed: 342 mph (550 kph)
Typical range: 620 miles (1,000 km) with normal payload of 5,070 lb (2,300 kg)
T/O run: 700m
Ldg run: 360m
Cargo: 5070 lbs
Engines: 3 x turbo-jet AI-25, 14.7kN
Max take-off weight: 12400 kg / 27337 lb
Empty weight: 8500 kg / 18739 lb
Wingspan: 25.0 m / 82 ft 0 in
Length: 20.2 m / 66 ft 3 in
Height: 6.5 m / 21 ft 4 in
Wing area: 70.0 sq.m / 753.47 sq ft
Cruise speed: 550 km/h / 342 mph
Range w/max.fuel: 1600 km / 994 miles
Range w/max.payload: 600 km / 373 miles