Leonardo this week marked the 20th anniversary of the first flight of its AW139 intermediate twin helicopter. The worldwide fleet of 1,100 aircraft delivered has amassed more than three million flight hours since the model entered service in 2004.

The Italian manufacturer launched the new model in 1997, originally designating it as the AB139 when it was being jointly developed with Bell. In 2005, then-AgustaWestland (now Leonardo) took sole ownership of the program, paying Bell $95 million for its 25 percent stake.

Today, Leonardo plants in Vergiate, Italy, and Philadelphia, Pennsylvania, produce the helicopter, with more than 280 customers in 70 countries now operating the machine. According to Leonardo, AW139s account for about half of the global helicopter fleet used for search and rescue and air ambulance, law enforcement, fire-fighting, disaster relief, and military missions. The model also has a strong presence in the offshore energy market, where AW139s are increasingly replacing larger helicopters.

Capabilities added to the AW139 over the years include 1,000 mission kits and equipment, wireless data loading, synthetic vision, enhanced ground proximity warning system (EGPWS), anti-icing systems, and an increased mtow from 14,110 to 15,432 pounds.