I've just come home from a vacation, flew Frontier on all flights. I couldn't help but notice that they seem to use the same thrust at takeoff as through the climb. Does anyone know if they are derating takeoff thrust to the point that it works for climb thrust, or what else is happening? Just curious.Thanks, Bruce

Did you sit behind the wings/engines? I'm sure they switch to climb thrust at the acceleration/flaps retraction altitude, but it is hard to decipher the change in thrust behind the wings, as opposed to sitting ahead of the engines. I've noticed this in youtube videos and my travels as well, but rest assured they can't run the engines at takeoffthrust for the whole climb sequence, jet engines can only run at takeoff thrust for about 5 minutes or so.

Hi Bruce - Whilst I quite often fly the Wilco A319 on FSX and I have been in an Airbus Simulator, I don't pretend to be an expert on the matter. As a slight aside I have been involved with jet engine performance testing for many years. Therefore, I'll have a go although someone might well correct some of what I say - so here goes ........The A319/320/321 series aircraft were among the first to have very sophisticated and complex systems operations aimed at optimising engine and aircraft performance, complying with environmental requirements all without compromising safety - nothing too much out of the ordinary there but there are some constraints plus many options open to the crew in terms of flight performance planning. As we know it is highly desirable to limit Take Off and Climb thrust and this can be achieved depending on ambient pressure and temp, runway length, altitude and aircraft gross weight. All these factors (and many more) are fed into the Flight Management Computer (and the other related Computer Systems) which then determine the optimum performance profile and hence the ideal T/O and Climb settings. The chosen setting for these two activities can then be selected by the pilot through enabling the Auto Throttle setting on the Auto Pilot and ultimately, the Throttle Levers. The throttle levers operate in two different modes - 'manual range' where the levers control engine power in the traditional way or by one of four predefined settings or 'detents' namely 'Idle', 'Climb', 'Flex' and 'Take Off/Go Around (TOGA)'. Idle and TOGA speak for themselves however 'FLEX' is a power setting that permits a reduced thrust takeoff based upon satisfactory compliance with the parameters described above. If a FLEX take off is viable then that is probably what the pilot will select by moving the Throttle Levers to that detent on the quadrant. Once airborne and the aircraft is 'clean' I belive the pilot will then move the Throttles from the FLEX to the Climb detent (they are adjacent on the quadrant). I suspect that in most cases there is very little difference between the characteristics of these two settings which is why I believe your instincts and senses were telling you that T/O and Climb thrust were the same plus of course the point about the difficulty of detecting changes in thrust that 767fan makes in his response.. Needless to say should the pilot so wish or indeed need to then these settings can be overidden by him simply taking hold of the throttles and moving them 'manually' to wherever he wishes. Notwithstanding this the FADEC (Full Authority Digital Engine Control) will always prevent the engine overspeeding or over temping beyond it's design limitations.I hope this helps and doesn't confuse - it is a complicated subject. Darkened room for me now!!!Roger

Hi 767fan and Roger,Thanks for your replies, much appreciated. My seats on both flights were forward of the wing, one was 1A (as far forward that one can be as a pax), the other in 8F (right next to the engine thrust reverser). It may be that, as you say, the derated takeoff and climb thrust were close enough not to notice (the flights were 3 and 4 hours respectively, fairly long for this type of aircraft I assume).Thanks for the detailed explanation of the engine performance parameters too.Thanks, Bruce.