Transition to Climb

[dlrk]

How should the transition to climb be accomplished? I tried using FLC with ATS in N1 CLB, but it immediately pushed up the throttles to the N1 climb rating, overshot the set speed of 250, then pitched up to 15 degrees and climbed at 6000 FPM before stabilizing at 250 knots and a more reasonable pitch.

[Graeme_77]

This is indeed a quirk of the Challenger autothrust system as the pitch modes can't anticipate the power increase or respond quickly to a full power application due to the ATS and AP being totally discrete systems.

You can disconnect the ATS, engage FLC then increase power a little bit to enter a gentle climb, this is a common procedure on the Challenger. Alternatively you can "ease" the aircraft into the climb with VS mode, or pitch mode. About 10 degrees nose up is good for low altitude climbs, and 5 degrees for 10-20000ft. After that, FLC mode will be gentle enough even with ATS engaged.

Edited January 10, 2022 by Graeme_77

[flanisher]

Takeoff with pitch mode (not v/s or flc) and use the VS up/down wheel to set your climb angle down to 10 degrees after you have cleaned up the plane after takeoff, then dial your speed up!  This works well for me.

[JT8DNoise]

On a typical departure, where terrain or obstacles are not a factor, at 400 feet the pilot flying (PF) asks for vertical speed mode. This is typically done where you have a low level off right (KBFI) right after departure, if you use FLC, the pitch angle is too high and you will likely overshoot the level off. If you were on a departure in mountainous regions (KASE or CYLW) or terrain is a concern, at 400 feet the PF will ask for FLC 250. A typical after takeoff check: landing gear up, flaps up, thrust reversers off, ignition as required, 10th stage bleed transition (Right 10th stage bleed press in, 10th stage isolation press out, left Left 10th stage bleed press in, APU LCV press out, climb thrust set (this is done through the FMS CDU (press PERF, select CLB) - Thrust Limit page. N1 Climb is displayed on the primary EICAS page, ATS window. Pressurization would be checked (building diff pressure), and CAS messages would be verified as checked (nothing unexpected). Rob 

[dlrk]

Last couple flights I've been using pitch mode or handflying to keep the pitch not above 10 while letting the ATS keep the speed at the 200-250, then for further climb using FD SYNC to bring the pitch to 10, then hitting FLC once thrust has stabilized

[Graeme_77]

That's very close to what I've been doing, what our SMEs recommended and avoids FCP inputs when hand flying - that's the reason why that procedure is described in the Takeoff section. 

[Gábor]

10 hours ago, dlrk said:

Last couple flights I've been using pitch mode or handflying to keep the pitch not above 10 while letting the ATS keep the speed at the 200-250, then for further climb using FD SYNC to bring the pitch to 10, then hitting FLC once thrust has stabilized

Where to find FD SYNC button or switch?

[Ed Moore]

18 minutes ago, Gábor said:

Where to find FD SYNC button or switch?

It's in the binds under the Captain Pedestal section. Search for sync.

[wyhhero]

Thank you for sharing this information. Just looking for this operation tech for taking off rather than let the aircraft soaring high into the sky like a rocket.