Worldwide Aircraft was the initial non-OEM modifer and STC holder for the ATR42 and 72 from passenger to freight currently operated by some of the largest Freight Expediters around the world. Our STC included changing the aft airstair door to upper hinged freight door, internal opening of the main forward cargo door. Low cost metal window plug reinforced cargo floors.
The ATR 42 is a twin-turboprop, short-haul regional airliner built in France and Italy by ATR (Aerei da Trasporto Regionale or Avions de Transport Régional). ATR and Airbus are both built in Toulouse, sharing resources and technology. The name "42" comes from the aircraft's standard seating, which varies from 40 to 52 seats. First announced in 1981, the ATR 42's first maiden flight was August 1984 and production of the original model, the ATR 42-300 ran until 1996.
The ATR 42 came in six major variants:
ATR 42-200 First prototype model with very few actually made. It was succeeded by the production model -300
ATR 42-300 This was the standard production version of the aircraft and was produced until 1996.
ATR 42-320 The 42-320 was basically the same as the -300 model, with the exception to a minor engine upgrade which boosted it's performance from 1,800 shp to 1,900 shp and gave it better overall performance in hot or high altitude conditions.
ATR 42-400 The 42-400 became the official name for the passenger version of the ATR 42 "Surveyor". The 42−400 was an upgraded version of the 42−200/300/320 using six-bladed propellers on the same PW120/PW121 engines.
ATR 42-500 First debuting in 1995, the 42-500 model was significantly upgraded to include new PW127E engines rated at 2,400 shp, new electrically controlled props made from composite materials, a new cabin design and increased weight capacity. Because of the newly designed cabin and use of six propellers, the overall in-flight noise was reduced.
ATR 42-600 The 42-600 was announced in October 2007 and began operations the second half of 2010. With this upgrade comes the new PW127M engine which allows for shorter takeoff conditions. Also upgraded, are the entire avionics package and inclusion of a Multi-Purpose Computer for additional safety and control.
Additional Variants The ATR 42 also shipped as bulk (Tube Versions) and ULD Freighters (Large Cargo Door). A STC is available to convert all ATR 42 variants to all-cargo transport aircraft.
Specifications General characteristics
Crew: 2 Capacity: 42–50 passengers
Length: 22.67 m (74 ft 5 in)
Wingspan: 24.57 m (80 ft 7 in)
Height: 7.59 m (24 ft 11 in)
Wing area: 54.5 m2 (587 sq ft)
Aspect ratio: 11.1:1
Empty weight: 11,250 kg (24,802 lb)
Max takeoff weight: 18,600 kg (41,006 lb)
Powerplant: 2 × Pratt & Whitney Canada PW127E turboprops, 1,610 kW (2,160 shp) each
Cruise speed: 560 km/h; 350 mph (300 kn)
Range: 1,555 km (966 mi; 840 nmi) with 48 passengers
Service ceiling: 7,600 m (24,934 ft) 
Takeoff Run at MTOW: 1,165 m (3,822 ft)