B737NG, thrust/pitch mode selection

[Shiny side down]

When I first flew the NG, about a decade ago, the call was N1-bug 'up'. It was fairly natural and concise. Both crew were understood to be trained on the type, and it was a standard call.

N1 sequencing to the climb thrust ( or taking it out of take off thrust?)
Bug 'up' being to bug the flaps up speed. Now, we apparently need to say 'set flaps up speed' or some limited variation.

But I'm curious about this.

Old call
'N1-bug up'

Latest version
'N1-level change- set flaps up speed'

Is this really necessary to choose 'N1' and then immediately 'level change'? Or is there some factor that I have missed in the years away from the fleet? Or some event where the extra call is now mandated?



N.B
No doubt someone really clever is going to pick holes in both the question, and presentation of the problem, and all the answers that come hereafter. To you, I say, in advance, thank you for avoiding giving an answer while muddying the waters.

[Denti]

We moved away from the old N1 Speed UP call to just the next required flap setting. To achieve that we select LNAV/VNAV and AT to ARM at the gate, thrust "reduction" and speed selection is done by VNAV depending on normal operation or OEI automatically.

[Shiny side down]

I was used to initially using

Take off thrust to acceleration altitude
N1-bug up to clean up
Then flight level change

The next operator advocated
take off thrust
N1-bug up
VNAV (or flight level change if deemed appropriate, such as when you forget to put in 250/10000)

A recent operator has used
Take off thrust
N1-flight level change-set flaps up speed to clean up
VNAV/speed intervene thereafter.

I'm particularly curious about the benefit of selecting N1, and then level change immediately after. Especially as acceleration is generally 800-1000', and always above 400'.

[ImbracableCrunk]

How about this:

NOTE: Automatic thrust reduction is inhibited when engaging LVL CHG or V/S modes until 2 1/2 minutes after liftoff.

My question would be: Why are you going to LVL CHG before you are at FLAPS UP?