Setting N1 on Approach: B737-800

[Callsign Kilo]

Hello guys

Various ways have been discussed with me in regards to setting your N1 on approach when fully configured with either Flaps 30 or 40. Ball park figures to start of with are 55-56% N1 for F30 and around 64% for F40. Recently I was told that in order to establish a rough N1 setting for approach you should take your estimated landing weight from the FMC and use this as an N1 setting for F40 (ie 61t = 61%) or take the mass minus 5% for F30 (or was this the other way about??). Until now, I have been taking a rough figure and working from this after disconnecting the A/P and A/T. However I feel I should be more accurate.

[Blinkz]

There is no highly accurate way, they are all rough estimates and should be treated as such! Just use whatever power is needed at the time....

[The Real Slim Shady]

The numbers just give you a ballpark setting to refine according to the conditions and the performance you get.

[Jet Fuel Addict]

I have learned a good way indeed is to use landing weight for flaps 40, and landing weight minus 7 for flaps 30.
However if you're really light this figure for flap 30 doesn't work anymore so I try never to go below 52% N1 (as a reference off course, I'll go below and/or finetune it as need be...)

[misd-agin]

Slim Shady's got it right -I use ballpark settings all the time but I tell guys -"These 'SWAG's' (Scientific, Wild *ss Gueses) get you close. After that you're a pilot, figure it out."

[BelArgUSA]

Pilots who "need" a power setting need to learn "how to fly" basics first...
Call that power setting - a N1 or EPR... or even (like I have seen) a FF...!
:rolleyes:
xxx
All you have to know - for takeoff - is to move the thrust levers FORWARD...
Initially, spool up the engines to "something" like (N1) 80-85%...
Then move thrust levers further forward, to the target T/O N1 or EPR...
If you call "SET POWER", the PNF will do that for you.
All you have to do is keep your hand ready in case you want to reject the T/O.
And your power should be set by the time you reach 80 KIAS...
:ooh:
xxx
Now for approach and landing...
You descent whatever speed, and want to be 250 at FL100.
Well, somewhere around FL120 or so, move thrust levers all the way BACK.
Pure magic, your speed will slowly slow towards 260... and further down.
That is the time you bring SOME power FORWARD again.
If it looks like it continues to reduce a lot - move thrust lever FURTHER FORWARD.
Until it stays around 250, as you wish.
:E
xxx
Further descent - houses get bigger - slow down for flaps...
Little power reductions or increases as you call each FLAP SETTING.
FORWARD (when getting too slow) - or BACK (when getting too fast).
Follow the glide slope using your pitch trim... small trickle inputs.
Slowing too much...? Add ONE KNOB WORTH of thrust levers FORWARD
Then when back on your speed, reduce ONE HALF KNOB thrust levers BACK.
Going too fast...? - PULL BACK thrust levers ONE KNOB.
Back to your speed... Move thrust levers FORWARD ONE HALF KNOB.
:ok:
xxx
For landing, when the other pilot's face turns green - time you flare.
Now - did we talk about N1 or EPR (or FF) here...? Nooooooo.
Real aviators still fly (a little) with the seat of their pants.
Our IQ is not high enough to look at these many clocks labeled N1 and EPR.
I admit, I failed to pass my check on a Microsoft FS747, sorry.
xxx
:p
Happy contrails

[kijangnim]

Greetings,

It is good to have a target, then you fine tune it.
Use the flight with unreliable air speed table , enter it with your landing weight, get your N1 (EPR) correct it for temperature and wind, and use it as a target :ok: