New Airbus SOP, and Trim

[MD83FO]

Noticed that Airbus has hot addressed the nonstandard habit of calling the flight control page after engine start to set the takeoff trim.
I wish they were more specific so that people can confidently refer to the fuel prediction page and set the trim on the wheel, while comparing it to the Loadsheet takeoff CG for gross error.

i think the habit of pushing the sidestick to call the flight control page is widely used and looks very untidy and unnecessary.

i hope the airbus gods can read this and provide some hope.

[vilas]

Noticed that Airbus has hot addressed the nonstandard habit of calling the flight control page after engine start to set the takeoff trim

this practice standard or non standard was stopped after setting of the trim by percentage was introduced.

[iggy]

Now that we are talking about it, is there any official allowance between the GWCG figure from the FUEL PRED page and the value of the TOCG from the load sheet?

I've notice that is hardly the samea and usually different by around 0.2 or so. If there has been a mistake in the input (typically introducing the TOCG value from the load sheet as the ZFWCG) then the difference is evident, but I wonder if there is an official value that should trigger a check from the flight crew.

Thanks!

[Check Airman]

Originally Posted by iggy

Now that we are talking about it, is there any official allowance between the GWCG figure from the FUEL PRED page and the value of the TOCG from the load sheet?

I've notice that is hardly the samea and usually different by around 0.2 or so. If there has been a mistake in the input (typically introducing the TOCG value from the load sheet as the ZFWCG) then the difference is evident, but I wonder if there is an official value that should trigger a check from the flight crew.

Thanks!

My company is happy as long as the two values are within 5.0. Seems like a lot to me, but that's what it says.

[FlightDetent]

Is not the FCOM proc for the PM to set the TKOF-CG on the wheel from the LDS directly, without reference to FMS inputs or any other screens?

A320.

[sonicbum]

Originally Posted by FlightDetent

Is not the FCOM proc for the PM to set the TKOF-CG on the wheel from the LDS directly, without reference to FMS inputs or any other screens?

A320.

Absolutely. If I remember correctly there also used to be (many moons ago) the reference to the fuel prediction page in the Airbus PDPs... we used to have it as an FCOM procedure as well again several years ago. As of today we only do the crosscheck on the A330.

[FlightDetent]

Of course. Any mid-steps only create room for error.

I can understand the motives of people from the A300/310 (trim wheel-scale in units) or A330 et al (loadsheet not the ultimate CG reference due to trim-tank). The benefit of forcing the THS entry into the MCDU on the single-aisle does, however, escapes me a bit, as I do not buy the benefits of "THS disagree" warning.

[Fursty Ferret]

It's a minor thing IMHO because provided the aircraft is loaded correctly you can safely get airborne regardless of the trim setting (well, presumably within the range of not triggering a config warning).

I never looked at the flight control page since I had a percentage figure to go from.

I believe at least one large carrier doesn't move the trim from zero.

[vilas]

​It's a minor thing IMHO because provided the aircraft is loaded correctly you can safely get airborne regardless of the trim setting (well, presumably within the range of not triggering a config warning).​​​​​​

It's true at least for A320. For all old MSNs the entry of Stab setting into the PERF page was nothing more than a scratch pad entry. If you entered rightly, wrongly or didn't enter at all never triggered any warning. But correct aircraft loading is always important. Long ago there was a discussion here in which wrongly loaded A320 the nose came up as the thrust was set and could not be brought down till Thrust was reduced.

[Check Airman]

Originally Posted by Fursty Ferret

I believe at least one large carrier doesn't move the trim from zero.

Well that’s certainly different. Any insight as to why?

[nnc0]

As long as the subject is being discussed - does anybody use the TAKEOFF CG / TRIM POS graphic in the QRH? .

[FlightDetent]

No.

An example company is using laminated single-sheet copy of the original NCL. To ease the burden of housekeeping among individual airframes and sub-types (different diagrams), the Flt Ops wizard managed to remove the graphic. Happiness ensues for SAFA.

​​​​​

[PilotLZ]

The A320 FCTM says that, as long as the trim is within the green band, the takeoff is safe. Rotation characteristics may vary though. But the latter can also be the case if the calculated CG from the loadsheet is slightly off because the real distribution of the load doesn't fully match the calculated one. It can happen on flights with a low number of passengers who get to sit wherever they please. Although that's more of an anecdotal evidence, based on experience and observations, they tend to distribute themselves as evenly throughout the cabin as no computer would distribute them.