janjoensson 54 Posted August 3, 2021 Share Posted August 3, 2021 Hi! This is a question strictly out of interest, not a support issue. When on ground taxing the CRJ 700, with wing anti-ice turned off, you need a little bit of throttle power to start moving. However, when turning the wing anti-ice on, the engines spool up a bit and the CRJ moves on idle. Is that how the aircraft behaves also in real life? I think it is very handy, but would be interesting to know if anyone knows why and if this happens also in the real plane. Best regards Jan Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted August 3, 2021 Aerosoft Share Posted August 3, 2021 I suggest posting this in the CRJ forums. Link to comment Share on other sites More sharing options...
janjoensson 54 Posted August 3, 2021 Author Share Posted August 3, 2021 53 minutes ago, Mathijs Kok said: I suggest posting this in the CRJ forums. Oh, sorry, I thought I did. Must have mixed things up... Link to comment Share on other sites More sharing options...
Developer Hans Hartmann 3694 Posted August 3, 2021 Developer Share Posted August 3, 2021 Yes. Anti-ice systems need bleed air, and to produce more bleed air, the idle N1 is increased. For cowl anti-ice only, it's to about 30% and for cowl and wing anti-ice it's 35%. Link to comment Share on other sites More sharing options...
janjoensson 54 Posted August 3, 2021 Author Share Posted August 3, 2021 6 minutes ago, Hans Hartmann said: Yes. Anti-ice systems need bleed air, and to produce more bleed air, the idle N1 is increased. For cowl anti-ice only, it's to about 30% and for cowl and wing anti-ice it's 35%. Thank you very much for this informativa answer! Is it normal to taxi with wing and cowl anti-ice on, or is it normally turned on in a later stage during flight? Link to comment Share on other sites More sharing options...
JRBarrett 675 Posted August 4, 2021 Share Posted August 4, 2021 19 hours ago, janjoensson said: Thank you very much for this informativa answer! Is it normal to taxi with wing and cowl anti-ice on, or is it normally turned on in a later stage during flight? Using cowl anti ice during taxi would be standard practice any time the outside air temperature is below 10C and visible moisture exists (rain snow or fog). I’m not sure about the use of wing anti ice on the ground in the 700/900 series. I work (in maintenance) on CRJ200s, and the maintenance manual cautions that when testing the wing anti ice on the ground, to leave it enabled only long enough to do the required tests and then turn it off, otherwise the leading edges could overheat and become damaged. The 700/900 may be different. This would be a question for one of the r/w pilots on the test team. That said, our 200s are equipped with an optional “low temperature wing anti-ice system” that can be used for an unlimited amount of time on the ground. This system supplies bleed air at reduced pressure and flow rate (with temperature regulation) providing sufficient heating to prevent freezing precipitation from accumulating on the leading edges but not enough to potentially damage the leading edges from overheating. The LTWAIS may be unique to the 200. Because that model has no slats, it is far more likely to experience degraded lift on takeoff if there is any leading edge contamination. Link to comment Share on other sites More sharing options...
janjoensson 54 Posted August 4, 2021 Author Share Posted August 4, 2021 2 minutes ago, JRBarrett said: Using cowl anti ice during taxi would be standard practice any time the outside air temperature is below 10C and visible moisture exists (rain snow or fog). I’m not sure about the use of wing anti ice on the ground in the 700/900 series. I work (in maintenance) on CRJ200s, and the maintenance manual cautions that when testing the wing anti ice on the ground, to leave it enabled only long enough to do the required tests and then turn it off, otherwise the leading edges could overheat and become damaged. The 700/900 may be different. This would be a question for one of the r/w pilots on the test team. That said, our 200s are equipped with an optional “low temperature wing anti-ice system” that can be used for an unlimited amount of time on the ground. This system supplies bleed air at reduced pressure and flow rate (with temperature regulation) providing sufficient heating to prevent freezing precipitation from accumulating on the leading edges but not enough to potentially damage the leading edges from overheating. The LTWAIS may be unique to the 200. Because that model has no slats, it is far more likely to experience degraded lift on takeoff if there is any leading edge contamination. Thank you very much! Very interesting information Link to comment Share on other sites More sharing options...
KuntaKinte 210 Posted August 5, 2021 Share Posted August 5, 2021 Ok, I 'd like to chime in here. This is one of the cases where the AS CRJ does not behave like the real aircraft. As you can see in the first video of a CRJ 900 (in this regard not different to the CRJ 700), which was recorded before takeoff, there is no increase in engine RPM on ground - not even with both WING and COWL A/I ON. There is a slight rise in ITT, but the RPM remains in (after landing: reverts to) ground idle, which on some aircraft can trigger a L/R WING A/I caution message, indicating an underheat condition. This is acceptable on ground since WING A/I is switched ON not until line-up clearance and switched OFF shortly after leaving the runway. BTW: In the video you can also see, that the use of anti-ice always cancels a previously entered FLEX thrust, which does not happen on the AS CRJ. Anti-ice in flight is a different story. The second video shows what happens when WING and COWL A/I is switched ON in idle descent. While COWL A/I alone has almost no (if any) effect on performance, the use of WING A/I causes FADEC to raise the engine idle RPM automatically to ensure that the airpressure in the pneumatic duct is sufficient for effective wing anti-icing. This results in a considerable increase of engine thrust, that must be taken into account for descent planning. During climb it's the other way around: Using WING A/I causes a significant loss in climb performance, which can negatively affect the ability to meet altitude restrictions etc. That's why it is permissible to switch WING A/I to OFF with no ICE message and airspeed > 230 kts. Long story short: In the real aircraft WING A/I is the main culprit for de-/increased engine thrust in flight - on ground there is no such effect. So, this subject (including FLEX thrust) needs to be reworked by AS. Please login to view this video. Please login to view this video. Link to comment Share on other sites More sharing options...
KuntaKinte 210 Posted August 6, 2021 Share Posted August 6, 2021 Since this topic requires support, I would appreciate this thread to be moved to the "Systems" section. Link to comment Share on other sites More sharing options...
KuntaKinte 210 Posted August 10, 2021 Share Posted August 10, 2021 Could someone of the AS representatives please acknowledge that the findings pointed out above are on the tracking list? Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted August 10, 2021 Aerosoft Share Posted August 10, 2021 Yes they are. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.