LFPG 0 Posted August 20, 2014 Share Posted August 20, 2014 Hi! What is speed range for Airbus? Link to comment Share on other sites More sharing options...
Emi 5161 Posted August 20, 2014 Share Posted August 20, 2014 In which altitude, at which weight, which external situation? Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 I have missed TOD. I read this "If there were no other speed restrictions, as xxxx said, the fmgs will pitch down more to get the speed on the upper part of the speed range it sets up" I am now passing waypoints, over the required altitude with speed managed. I don't know what is speed range! Could you please explain? Link to comment Share on other sites More sharing options...
Emi 5161 Posted August 20, 2014 Share Posted August 20, 2014 On the PFD you got two magenta lines when descending in managed mode, one above and one below your target speed. That's your speed range. Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Could you please show a photo? Thanks Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 And what is the upper part of the speed range? Could you please explain what I read? Does the speed range means that we have to be between it? If yes, does it mean that our plane is not always at the target speed? "If there were no other speed restrictions, as xxxx said, the fmgs will pitch down more to get the speed on the upper part of the speed range it sets up" How can there be a speed range without any speed restrictions? Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Thanks a lot --- and emi See what I found: "Managed Descent Speed Range In DES mode and in ECON/Auto speed mode, these two half triangles replace the selected speed symbol. They show the upper and lower speed limits calculated by the FMGC. The magenta equal sign indicates the target airspeed. The upper limit is the target speed + 20 knots, but will not exceed VMAX, VMO-3 or MMO- .006 whichever is lowest. If a speed limit or speed constraint applies, the upper margin is limited to ECON SPD + 5 knots. The lower limit is the target airspeed - 20 knots but no lower than Green Dot, F speed, S speed or VLS, whichever is higher." So does it mean that in normal case, the plane will not cross +5 knots. But if we are running late in altitude, the plane will pitch down and the speed of waypoints (not constraints) can be flown at target speed+ 20 knots during the descent. -AGOPA: FL200- 340 knots -LORNI: FL170- 320 knots -BANOX: FL150- 290 knots -MOPAR: FL120- 270 knots If we are FL230 and passing over AGOPA, 340 knots and we enter FL175 in the FCU, the plane will pitch down, thrust idle but it can be between 320-340 knots. When we will level off, at FL175, it will come back to 320 knots. So is this range only used when a plane is not flying at the right altitude at the right moment in managed mode? Will it regain it's "+5" knots after having regained it's descent profile? In a normal case, the plane would't have to pitch down "more or less brutally". So is it only used during managed mode, TOD missed? Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Yes ---, you are right. But what is the +5 thing? I didn't really understand... and the +20 thing? Thanks a lot Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 But it says that the upper range is the speed+ 20 knots! I don't understand why +5 knots is not normal... with pitch control, it's equal to +/- 2knots... Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Ok thanks, So in managed mode with speed restrictions it will be +5knots and in speeds programmed by the FMS, during descent, the plane will allow +/- 20 knots with idle thrust. In my example, as we are pitching down and if the LORNI waypoint is programmed by the FMS, it can fly it between 300 and 340 knots... Am I right? Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Thanks, So if we have LORNI as a speed restriction, it will slow down at full idle thrust and will slow down slowly, to match FL170, but also to be at 320-325 knots, right? But is there something for climb or even cruise? Thanks Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 And I imagine that the +/- 20 knots are only reached only when there is a very low pitch... But could you give an example with speed - 20knots during descent? Thanks Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Oh! Great! Thanks! Last question: These are waypoints programmed by the FMS! But MOPAR is a speed restriction -AGOPA: FL80- 220 knots -LORNI: FL60- 210 knots -MOPAR: FL50- 205 knots We are now flying at FL90 over AGOPA, 220 knots and we enter FL50 in the FCU, the thrust goes to IDLE and speed get's maintained by pitch inside the range +20/-20 knots. But idle thrust get's too low and get's at 200 knots, bellow the speed restriction of MOPAR, when it will level off at LORNI, will it accelerate to 210 knots and will then descend slowly to be in the range of 205/210 knots? Thanks Link to comment Share on other sites More sharing options...
LFPG 0 Posted August 20, 2014 Author Share Posted August 20, 2014 Ha ha! Thanks a lot ---! Link to comment Share on other sites More sharing options...
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