Haseen - I agree with FE H here as well. My tables show a clean Green Dot speed for a 175 at 32 tons of about 190 Kts. Therefore slowing up to 170-180 to intercept the LOC would be a good idea. If it means using Flaps 2 or 3, then so be it.

PM

@ Piltdown.
The flap for go around was down to slightly different amc for missed approach performance. The guys at Embraer told me it was due to when the engine is considered to fail.

Then because they had the performance data for F2 approach climb they offered it the EASA customers as an option $$$$. Just as the have expanded temperature options and CG options each of which were done to secure a deal with one airline and then offered as an option to others.

Thanks Piltdown for replying. Feelthere only provided takeoff & landing speeds.. no green dot speed table.

Embraer 175 195 VNAV Auto FMS Speed.
 

Dear:

After take off and AP engagement, when VNAV is selected, speed remains at takeoff speed with speed selector at AUTO/FMS. When will it accelerate to climb speed automatically?

Acceleration should take place when you select LVLCH providing the criteria set in the Departure Speeds page are met (altitude or distance). Failing that use manual speeds and increase the target speed to one you wish to fly at during flap retraction (Flaps 1, say 210 Kts) and 250 Kts when clean.

PM

Dear Piltdown Man:

Thanks for being in touch.

1. By LVLCH, do you mean pressing LVLCH botton or VNAV button? Because LVLCH botton causes normal LVLCH (open loop) and VNAV causes magenta LVLCH meeting the alt/speed constraints.

2. The FMS Departure speed page shows the following default data:
speed restriction: 200 Kts, altitude: 2500 ft., dist.: 4 NM.

3. But after 1000 ft., with speed selector at FMS mode when I engage AP and press VNAV, speed target maintains v2+10 kts (Magenta) and never accelerates. Even LVLCH button does not help. When I select MAN speed mode and select higher speed manually, say 200 kts, the plane accelerates as demanded.

4. Am I making any mistake? or that's a bug in the Feelthere simulation?

First off I'd like to thank the other respondents on this thread for being uncommonly kind to a simmer and providing the sort of detail we ground-hogs can only drool over.


Haseen, I have the feelthere e-jets and I can't reproduce what you're getting. I've just had a go with the 175.

- Setting the AT source to FMS on the ground, flaps 1, gave a speed target of 151 knots (V2+20 at my weight);

- after taking off, at around 400ft, the speed target increased to 200 with green dot at 205. Engaging the AP and AT, the aircraft (sorry, model!) accelerated as expected;

- passing 2500 ft. the speed target increased to 230 (VFE flaps 1);

- retracting the flaps at green dot changed the speed target to 240;

- passing 10000 ft the speed target changed to 290, which was the FMS commanded climb speed.


I can't vouch for the validity of the speeds but the logic seems correct.

There is nothing wrong and yes I do mean LVLCH. On departure, the aircraft is in Take Off mode. LVLCH selects selects climb power and accelerates the aircraft either to a speed manually entered or the one pre-selected in the the FMS. But please understand that if you departed with FMS speeds, the aircraft will not accelarate until either 2,500' or four miles has been flown, delending on the limit chosen.

PM

Dear PM:

Thanks for your reply. So there is the catch..the plane will maintain FMS speed till 2500ft. Now I get it. Thanks again.

So..a solution Haseen, would be to change the FMS speed parameters (assuming that you don't want to use manual speeds) to something that will suit you. My understanding is that the 200kts/2500'/4nm parameters are to satisfy FAR requirements not to fly faster than 200kts in Class C or D airspace. Try changing the 2500' to 1000' and the 4nm to 2nm.