Latvia’s Air Baltic restarted revenue flights with its Bombardier CS300s on Thursday after grounding all seven of its narrowbodies to attend to “technical nuances” involving their Pratt & Whitney PW1500G geared turbofans. It added that it expected to finish inspecting all seven of the airplanes on Thursday and clear them for operation by the end of the day.

“Air Baltic is working in close cooperation with aircraft manufacturer Bombardier and engine manufacturer Pratt & Whitney,” said Air Baltic in a statement. “Additional inspections are carried out in order to ensure the safety of the CS300 aircraft as well to perform the necessary upgrades to the aircraft.”

Air Baltic did not offer details on the source of the engine concerns, however, noting only that it had expected “additional attention” and reserve aircraft availability as part of the CS300’s introduction strategy.

“Similar to other technology sectors...in aviation there are certain technical nuances that are characteristic to new equipment that require additional attention and upgrades during the initial stages of exploitation,” the company added. “[The] CS300 is not an exception and similar to all new aircraft its introduction requires additional attention concerning the harmonization between different manufacturer parts and systems.”

Air Baltic added that the “harmonization” has proven successful and that the fleet has registered “very good results,” including fuel efficiency improvements of 21 percent compared with other aircraft in its fleet. Each aircraft spends between 85 and 95 hours in the air every week, the airline said.