When is the right time to replace aircraft engines? It all depends on the number of times the aircraft took off and landed. Scheduled aircraft used in the passenger transport service must be adequately maintained in order to have maximum safety on board and guarantee optimal use of fuel. But during its life an aircraft changes engines several times.

Various factors are monitored to determine when is the right time to replace a jet engine. Among these are flight cycles (numbers of takeoffs and landings), which measure the longevity of an aircraft, regardless of the distance flown. Arrivals and departures are in fact the most stressful phases for an aircraft's engines.

Another element is the size and material composition of the fuselage. Short-range narrowbody aircraft such as the A-320 last nearly 50,000 flight cycles, while long-range widebodies range between 25,000 and 45,000 cycles (B-747 has 35,000 flight cycles; B-787 Dreamliner 44,000).

Given that engines are overhauled two or three times before being decommissioned, an A-320 operating four short-haul flights a day uses three or four thrusters during its entire life span, which is at least 30 years of service. In fact, this entails lower costs for the companies than the continuous maintenance of the engine.