Chinese name: Yunshuji-12 (Transport aircraft 12)
Export marketing name: Twin Panda

TYPE: Twin-turboprop light transport

PROGRAMME: Initiated as uprated version of Y-12 (I); first flight 16 August 1984. Y-12 (IV) (B-569L, first flight 30 August 1993) received production approval September 1995.

CURRENT VERSIONS: Y-12 (I): Initial version (first flight 14 July 1982), with PT6A-11 engines; three prototypes and approximately 30 production examples built.
Y-12 (II): Major production version; higher-rated engines, no leading-edge slats and smaller ventral fin. Certified by CAAC 25 December 1985 and UK CAA (BCAR Section K) 20 June 1990.
Detailed description applies to Y-12 (II) except where indicated.
Y-12 (IV): Improved version with sweptback wingtips; modifications to control surface actuation, main gear and brakes; redesigned seating for 18 to 19 passengers; starboard side rear baggage door; maximum payload and maximum T-O weight increased. Further changes include Rockwell Collins or Honeywell com/nav for both VFR and IFR, plus optional colour weather radar. GPS, Omega navigation, wing and tail de-icing, and oxygen system. Domestic certification received 3 July 1994 and FAR Pt 23 approval on 26 March 1995; Indonesian certification 16 November 2000. Sichuan Airlines order for 20 (7 November 2000) assumed to be of this version.
Twin Panda: Abortive 1998-99 attempt for version of Y-12 (IV) to be completed and marketed by Canadian Aerospace Group.
Y-12E: Next-generation version for Chinese market, with 559 kW (750 shp) PT6A-135A engines (derated to 462 kW; 620 shp) with Hartzell four-blade lightweight propellers, strengthened structure, reduced noise levels and improved avionics. Announced at Airshow China, November 2000; passed CAAC preliminary design review 16 November 2000. First flight August 2001; award of CAAC type certificate announced 26 February 2002; launch customer Sichuan Airlines (option for 10).
Y-12F: Concept study for version with pressurised fuselage and retractable landing gear.
Y-12G: In design stage 2002-03 as dedicated cargo version with large side door and capacity for three LD3 containers.

CUSTOMERS: Over 110 built by Harbin by mid-2001. Venezuela considering purchase of 10 in late 2001.

COSTS: Batch of 15 PT6-engined aircraft valued at US$58 million (1999).

DESIGN FEATURES: Designed to standards of FAR Pts 23 and 135 Appendix A and developed to improve upon modest payload/range of piston-engined Y-11. Constant-chord high braced wings, with small stub-wings at cabin floor level supporting mainwheel units; basically rectangular-section fuselage, upswept at rear; non-swept tail surfaces; large dorsal fin; ventral fin under tailcone.
Wing section LS(1)-0417; thickness/chord ratio 17 per cent; dihedral 1° 41'; incidence 4°.

FLYING CONTROLS: Conventional and manual. Drooping ailerons, horn-balanced elevators and rudder; trim tab in starboard aileron, rudder and each elevator: electrically actuated two-segment double-slotted flaps on each wing trailing-edge.

STRUCTURE: Conventional all-metal structure with two-spar fail-safe wings and stressed skin fuselage; Ziqiang-2 resin bonding on 70 per cent of wing structure and 40 per cent of fuselage; integral fuel tankage in wing spar box; bracing strut from each stub-wing out to approximately one-third span.

LANDING GEAR: Non-retractable tricycle type, with oleo-pneumatic shock-absorber in each unit. Single-wheel main units, attached to underside of stub-wings. Single non-steerable nosewheel. Mainwheel tyres size 640x230, pressure 5.50 bar (80 lb/sq in); nosewheel tyre size 480x200, pressure 3.50 bar (51 lb/sq in). Hydraulic brakes. Minimum ground turning radius 16.75 m (54 ft 11½ in).

POWER PLANT: Two Pratt & Whitney Canada PT6A-27 turboprops, each derated to 462 kW (620 shp) and driving a Hartzell HC-B3TN-3B/T10173B-3 three-blade constant-speed reversible-pitch propeller. All fuel in tanks in wing spar box, total capacity 1,616 litres (427 US gallons; 355.5 Imp gallons), with overwing gravity filling point each side. No recent news of domestic WJ9 turboprop (442 to 520 kW; 593 to 697 shp). said to have been under development for Y-12 and other aircraft.

ACCOMMODATION: Crew of two on flight deck, with access via forward-opening door on port side. Four-way adjustable crew seats. Dual controls. Main cabin can accommodate up to 17 passengers in commuter configuration, in three-abreast layout (with aisle), at seat pitch of 75 cm (30 in). Alternative layouts for up to 15 parachutists, or all-cargo configuration with 11 tiedown rings. Passenger/cargo double door on port side at rear, rear half of which opens outward and forward half inward; foldout steps in passenger entrance. Emergency exit on each side at front of cabin and opposite passenger door on starboard side at rear. Baggage compartment in nose and at rear of passenger cabin, for 100 kg (220 lb) and 260 kg (573 lb) respectively.

SYSTEMS: Hamilton Sundstrand R70-3WG environmental control system. Hydraulic system (operating pressure 118 to 147 bar; 1,711 to 2,132 lb/sq in) for mainwheel brakes. Two 6 kW DC starter/generators, two 600 VA 400 Hz single-phase static inverters and one 43 Ah Ni/Cd battery for electrical power. Goodrich Type 29S-7D 5178 anti-icing system optional for wing, tailplane and fin leading-edges. Oxygen system optional.

AVIONICS: Comms: VHF-251 and HF-230 radio, AUD-251A intercom and TDR-950 transponder.
Radar: Honeywell 1400C, RDS-81 or RDS-82 weather radar optional.
Flight: ALT-50 radio altimeter, DME-451, ADF-650A, MKR-350 marker beacon receiver, KLN90 GPS receiver, VIR-351 VOR, GLS-350 glideslope receiver and PN-101 pictorial navigation display. Doppler navigation with satellite responder (Y-12 (IV). Omega nav) optional (for example, in mineral detection role).
Instrumentation: 20025-11324 airspeed indicator, 510-8D10 horizon, 101420-11934 encoding altimeter, 30230-11101 vertical speed indicator, 9551-BN541 bank indicator, LC-2 magnetic compass, ZWH-1 outside air temperature indicator, and ZEY-1 flap position indicator; dual engine torquemeters, interturbine temperature indicators, gas generator tachometers, oil temperature and pressure indicators, fuel pressure and quantity indicators; 309W clock; and XDH-10B warning light box.

EQUIPMENT: Hopper for 1,200 litres (317 US gallons; 264 Imp gallons) of dry or liquid chemical in agricultural version. Appropriate specialised equipment for firefighting, geophysical survey (for example, long, kinked sensor tailboom) and other missions.

DIMENSIONS, EXTERNAL:

• Wing span: Y-12 (II): 17.235 m (56 ft 6½ in)
• Y-12 (IV): 19.20 m (63 ft 0 in)
• Wing chord, constant: 2.00 m (6 ft 6¾ in)
• Wing aspect ratio: Y-12 (II): 8.7
• Length overall: 14.86 m (48 ft 9 in)
• Height overall: 5.675 m (18 ft 7½ in)
• Elevator span: 5.365 m (17 ft 7¼ in)
• Wheel track: 3.61 m (11 ft 10¼ in)
• Wheelbase: 4.70 m (15 ft 5 in)
• Propeller diameter: 2.49 m (8 ft 2 in)
• Propeller ground clearance: 1.325 m (4 ft 4¼ in)
• Distance between propeller centres: 4.96 m (16 ft 2½ in)
• Fuselage ground clearance: 0.65 m (2 ft 1½ in)
• Crew door: Height: 1.12 m (3 ft 8 in)
• Width: 0.65 m (2 ft 1½ in)
• Passenger/cargo door: Height: 1.38 m (4 ft 6¼ in)
• Width (passenger door only): 0.65 m (2 ft 1½ in)
• Width (double door): 1.45 m (4 ft 9 in)
• Emergency exits (three, each):
• Height: 0.68 m (2 ft 2¾ in)
• Width: 0.68 m (2 ft 2¾ in)
• Baggage door (nose, port):
• Max height: 0.56 m (1 ft 10 in)
• Width: 0.75 m (2 ft 5½ in)

DIMENSIONS, INTERNAL:

• Cabin, excl flight deck and rear baggage compartment:
• Length: 4.82 m (15 ft 9¾ in)
• Max width: 1.46 m (4 ft 9½ in)
• Max height: 1.70 m (5 ft 7 in)
• Floor area: 7.0 m² (75.8 sq ft)
• Volume: 12.9 m³ (455 cu ft)
• Baggage compartment volume:
• nose: 0.77 m³ (27.2 cu ft)
• rear: 1.9 m³ (67 cu ft)

AREAS:

• Wings, gross: Y-12 (II): 34.27 m² (368.9 sq ft)
• Ailerons (total, incl tab): 2.88 m² (31.00 sq ft)
• Trailing-edge flaps (total): 6.00 m² (64.58 sq ft)
• Fin, incl dorsal fin: 2.24 m² (24.11 sq ft)
• Rudder, incl tab: 3.34 m² (35.95 sq ft)
• Tailplane: 3.10 m² (33.37 sq ft)
• Elevators (total, incl tabs): 4.06 m² (43.70 sq ft)

WEIGHTS AND LOADINGS (A: Y-12 (II), B: Y-12 (IV)):

• Max usable fuel weight: A, B: 1,230 kg (2,712 lb)
• Max payload: A: 1,700 kg (3,748 lb)
• B: 1,984 kg (4,374 lb)
• Max T-O weight: A: 5,300 kg (11,684 lb)
• B: 5,670 kg (12,500 lb)
• Max ramp weight: A: 5,330 kg (11,750 lb)
• B: 5,700 kg (12,566 lb)
• Max landing weight: A: 5,300 kg (11,684 lb)
• B: 5,400 kg (11,905 lb)
• Max zero-fuel weight: A: 4,900 kg (10,803 lb)
• B: 5,188 kg (11,438 lb)
• Max cabin floor loading (cargo): A, B: 750 kg/m² (154 lb/sq ft)
• Max wing loading: A: 145.9 kg/m² (29.90 lb/sq ft)
• Max power loading: A: 5.74 kg/kW (9.42 lb/shp)
• B: 6.14 kg/kW (10.08 lb/shp)

PERFORMANCE (A and B as above):

• Max operating speed (V_MO) at FL98:
• A: 177 kt (328 km/h; 204 mph)
• B: 175 kt (325 km/h; 201 mph)
• Max cruising speed at FL98:
• A: 157 kt (292 km/h; 181 mph)
• Econ cruising speed at FL98:
• A: 135 kt (250 km/h; 155 mph)
• B: 140 kt (260 km/h; 162 mph)
• Max rate of climb at S/L: A: 486 m (1,594 ft)/min
• B: 468 m (1,535 ft)/min
• Rate of climb at S/L, OEI: A: 84 m (275 ft)/min
• B: 90 m (295 ft)/min
• Service ceiling: A, B: 7,000 m (22,960 ft)
• Service ceiling, OEI, 15 m (50 ft)/min rate of climb, max continuous power: A: 3,000 m (9,840 ft)
• T-O run, 15° flap:
• normal: A: 340 m (1,115 ft)
•  B: 370 m (1,215 ft)
• STOL: A: 230 m (755 ft)
• T-O to 15 m (50 ft), 15° flap:
• normal: A: 420 m (1,380 ft)
•  B: 490 m (1,610 ft)
• STOL: A: 370 m (1,215 ft)
• Landing from 15 m (50 ft), 20° flap; with braking and propeller reversal:
• normal: A: 480 m (1,575 ft)
• STOL: A: 370 m (1,215 ft)
• with brakes only:
• normal: A: 620 m (2,035 ft)
•  B: 630 m (2,070 ft)
• STOL: A: 200 m (656 ft)
• Landing run, 20° flap:
• with braking and propeller reversal: A: 200 m (660 ft)
• with brakes only: A, B: 340 m (1,120 ft)
• Range at econ cruising speed at FL98 with max fuel, 45 min reserves:
• A: 723 n miles (1,340 km; 832 miles)
• B: 701 n miles (1,300 km; 807 miles)
• Endurance, conditions as above:
• A: 5 h 12 min
• B: 5 h 15 min

The article appears in the following publication:
Jane's All the World's Aircraft 2004-2005. Jane's Information Group Ltd. 2004. ISBN: 0-7106-2614-2