High-bypass engines are typically intended for civilian applications and this moves the goal posts compared to military engines. Reliability, durability and support gain importance relative to raw performance, in addition to fuel efficiency. An engine which keeps grounding the aircraft due to frequent malfunctions or poor spares supply is a serious financial drag on an airline. Not only is it failing to earn money, it increases costs through maintenance man hours and parts. As a result, any deficiency in quality control is exposed mercilessly in this kind of environment.
So long as the difference in fuel burn isn't too big, this question of reliability can even tip the balance between two engine options one way or the other. It's for this exact reason that so far the LEAP-1A has outsold the PW1100G by about 60 to 40, even though the Pratt is unequivocally the more efficient of the two. Granted, the difference is only about 1 or 2 percent, but back when oil prices were lower, the RB.211 was able to outcompete the PW2000 on the 757 despite a much bigger fuel burn disadvantage.
Even when you nail the tricky subject of reliability, poor support can do you in, as the SaM146 on the SSJ100 demonstrates. On wing, it has achieved a 99.9% engine-related dispatch reliability (i.e. only one in a thousand flights is cancelled due to an engine break-down) and an overall (aircraft) dispatch reliability of 99.7%. That's A320/737NG territory, but once the engine comes up for scheduled maintenance or does malfunction once in a while, spares are very hard to come by, keeping it on the ground way too long. So long that Western customers CityJet and Interjet were forced to give up on it.
So long as the difference in fuel burn isn't too big, this question of reliability can even tip the balance between two engine options one way or the other. It's for this exact reason that so far the LEAP-1A has outsold the PW1100G by about 60 to 40, even though the Pratt is unequivocally the more efficient of the two. Granted, the difference is only about 1 or 2 percent, but back when oil prices were lower, the RB.211 was able to outcompete the PW2000 on the 757 despite a much bigger fuel burn disadvantage.
Even when you nail the tricky subject of reliability, poor support can do you in, as the SaM146 on the SSJ100 demonstrates. On wing, it has achieved a 99.9% engine-related dispatch reliability (i.e. only one in a thousand flights is cancelled due to an engine break-down) and an overall (aircraft) dispatch reliability of 99.7%. That's A320/737NG territory, but once the engine comes up for scheduled maintenance or does malfunction once in a while, spares are very hard to come by, keeping it on the ground way too long. So long that Western customers CityJet and Interjet were forced to give up on it.
Last edited:
