View Full Version : 737-400 Climb Power Question
rbbarker
13th Jan 2003, 15:47
Greetings all. My question concerns the procedures for establishing climb power in a 737-400. Assume that on a properly configured aircraft on the runway, throttles are advanced and stabilized, then advanced to 70% and TOGA engaged. V1...rotate...positive climb. Now, exactly what are the next few procedures with regard to MCP settings and the selection of climb power. I am doing research on this topic and can't quite grasp what happens. It is my guess that at around 400', HDG SEL is engaged and spun to the departures vectors so you can follow the FD. I also guess that VNAV is engaged at the same time so that the FMC controls climb power and you get vertical cues from the FD. Is this correct? Even close? Thanks for your time and assistance!
Boyd
Welcome to Pprune, I recommend that you read the following topic and then change your message accordingly......
http://www.pprune.org/forums/showthread.php?s=&threadid=76148
Mutt.
rbbarker
13th Jan 2003, 16:58
My background is that of flight simulation enthusiast, but don't be fooled...I am confident that I can comprehend a reply regardless of the level at which it was written. That having been said, I don't believe a PhD level response is necessary. I am simply concerned with the procedures related to MCP and climb power with regard to a climb-out under normal conditions. Is LVL CHG used? The N1 mode? Or LNAV as I suspect? Then at what altitude and/or condition is the mode engaged. I think it is becoming apparent at what information I am looking for. Hope someone can help. Regards, Boyd
Cakov
13th Jan 2003, 18:05
In the -400, we adavnce the thrust levers to about 40% N1, and once the engines are stable, push TOGA.
After T/O, either HDG SEL or LNAV is engaged at 400' (usually the departure is in the FMC, so LNAV is used). At acceleration altitude (typically 1000' above the airfield), N1 is selected, and the airspeed increased on the MCP to flaps up manouevring speed. The flaps are retracted as the aircraft accelerates.
Once the flaps are fully retracted, we select LVL change and wind the speed up as required, or select VNAV which takes control of the speed for us (250kts below FL100, then the most economical climb speed above that).
Those are the basics, but the procedure is often varied (departure not in the FMC, better rate of climb required, reduced rate of climb required (use Vertical Speed mode), speed restrictions cancelled by ATC, etc.).
Hope this is what you were looking for!
rbbarker
13th Jan 2003, 18:19
That is spot-on perfect. Just what I was looking for. Thank you!
RBB - be aware that 'acceleration altitude' depends on the way an operator calculates performance - 1500' AAL is not uncommon. The 737 is designed so that the whole acceleration CAN be flown if desired by selecting VNAV at acceleration altitude.
rbbarker
14th Jan 2003, 11:52
That's interesting as well. Thanks.