737- Fuel flow Vs. N1

Sidious

Well-Known Member
Hey guys,

So my company basically threw me into the airplane about a year ago and I've learned to fly approaches using N1. We have 700s and 800s. I can pretty well judge our various airports and weights of the plane and it works out.

However, I did my US type in a -300 a few weeks ago and all they stressed was Fuel Flows for approaches.

What do you guys use? I'm all for the thought process that, whatever works is fine but also if there is a better way then I'm all ears.
 
I flew DC8s with the CFM56 engines and fuel flow = airspeed seemed to work well. IE, 2500 pounds and hour = 250 knots. Don't know if that will help or not?
 
I flew DC8s with the CFM56 engines and fuel flow = airspeed seemed to work well. IE, 2500 pounds and hour = 250 knots. Don't know if that will help or not?


Yeah that was the thought process in the sim in the US and it worked pretty good. However, I was wondering how different weights and airport altitudes will change it. We routinely visit airports above 8000 ft. I guess I'll just note the FF and see whats easier. One thing that makes the N1 approach easy for me is that on the NG it is a massive gauge that is very easy to include in the scan.

Plus, one of our stabilized approach criteria is N1 not below 40%. I think that is why I started to look at it in the first place when I first hit the line.
 
I never got the fly a fuel flow thing, and im not a power setting guy. I mean, if someone asks "What will give me 200 Kts clean" I have no idea, if your slow add power, if you fast take it out. Basic stuff. Power setting change based on altitude, weight, temp, so its always been a mute point for me to learn them.

I will say this, I have flown many turbines that you can set an ITT value in a climb and it gets you your recommended climb n1.
 
Fuel flow is solid gouge for the sim, but I've always been an N1 guy in the jet, and even then, that's just a general figure. In the end, the N1/FF is whatever it takes to maintain what you want. I think we can all agree on that.
 
I think having an approximate N1 number works best for me. If you know that around 65% will give you 250 clean, you can mess with it as far as altitude, configuration and weight are concerned.

I agree with the ITT for climb, as long as you aren't blowing any other limitations obviously. Of course, I'll never understand the guys that have to fiddle constantly with the power get EXACTLY 99% N1 or whatever. Not in the climb anyway. I find setting the N1 1 or 2% below recommended will keep you in ITT and below N1 limits when the temp changes or whatever. You aren't losing that much power at 1 or 2 percent and not risking exceeding an N1 limit immediately.
 
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