Latest Antonov An-74 variant now firmly in flight-test trials

 - May 21, 2008, 9:25 AM

Ukraine’s Antonov An-74TK-300 made its international debut at this year’s Paris Air Show. First flown in April, the airplane had, as of mid-July, flown 35 times, including 20 missions for its certification program. It differs from the basic An-72/74 family of twinjets in its underwing engine pylons. The An-74TK-300’s Progress D36 powerplants use a thrust-reverser system derived from that on the An-124 Ruslan’s D18Ts, accounting for the only difference from the ordinary D36 series engines.

Previous An-72/74 variants have the engines mounted on top of the wing to produce a Coanda wing-overblowing effect and to protect the engines from stones and other foreign objects on takeoff and landing. Designers chose the configuration to please military customers requiring STOL (short takeoff and landing) performance. The penalty was high fuel consumption in cruise flight as wing overblowing produces extra drag, reducing the lift-to-weight ratio.

The An-74TK-300 was instead developed for commercial operations. According to Aleksandr Makiyan, Antonov’s leading test engineer, the new variant burns only 441 pph while cruising at 324 kt, which is some 102 pph less than the An-72/74. The airplane also has a higher takeoff weight, 82,670 lb compared with 80,470 lb for the An-74TK-200.

Although the aircraft displayed in Paris uses the same fuselage, Antonov plans to stretch it to seat 60 to 68 passengers instead of 52. That airplane would have a ferry range of 2,835 nm and 1,620 nm with 60 passengers, compared with 2,484 nm and 1,620 nm with 52 passengers. Makiyan said the flight-test and certification program calls for 300 to 400 flights over a one-year period. As a first step, a type certification to NLGS-3 Russian national airworthiness requirements is targeted. Later the airplane will be certified to AP-25, an analog of FAR Part 25. The An-74TK-300 would also meet the proposed ICAO Stage 4 noise requirements.

The An-74TK-300 cockpit features some new avionics, such as the Ukrainian-made SM3301 dual GPS receiver operating in three modes (Navstar, Glonass and two satellite constellations simultaneously). It also holds a BUR-92 flight data recorder that stores 150 parameters. Other innovations include the Orlan VHF radio with 8.33-kHz channel spacing, Arlekin long-range HF radio and a G-002M flight management system, which allows the pilots to control the functions of any of the major systems installed on the aircraft. The prototype features a first-class cabin layout with 52 French-built seats arranged four abreast.