Bombardier extended the intervals between major powerplant inspections on its Learjet 70 and 75 models to 3,500 hours, the company announced on Tuesday. The 500-hour extension, from 3,000 hours, will improve operator bottom lines by reducing the required inspections over the lifecycle of the twinjet's Honeywell TFE731-40BR engines, Bombardier said.

Bombardier unveiled the latest enhancement as the Learjet fleet collectively topped the 25 million flight-hour mark. The milestone occurred nearly 55 years after the first Learjet entered service in 1964, bringing among the earliest purpose-built business jet aircraft to the business aviation community.

“This is a significant milestone for our pace-setting Learjet aircraft family,” said Bombardier Business Aircraft senior v-p of worldwide sales and marketing Peter Likoray. “Reliability and longevity are two of the reasons customers among Fortune 500 companies continue to choose Learjet as the most trusted light jet platform.”

Bombardier acquired Learjet Corp. in 1990 and since has introduced eight new and upgraded models, including the Learjet 75, which entered service in 2013.

The company notes it continues to invest in new features for the Learjet family and in-service fleet, pointing to upgrades to the Garmin G5000 flight deck that are expected to be available on new and in-service 70 and 75s later this year. Unveiled last fall, the upgrades incorporate improvements in climb, cruise, and descent vertical navigation, along with takeoff and landing performance calculations, as well as an option for FANS-1/A+.