PDA

View Full Version : FMA help with NADP1


Airbus Bloke
13th Feb 2017, 08:19
I think I'm 90% correct already, but rather than confuse you with my potential errors I'm just going to ask the question directly.

NADP1 is 1500/3000.
Airfield Elevation is 100ft
Perf Page is therefore loaded with 1600/3100
Initial cleared altitude 3000ft

Can someone please talk me through the FMAs from take off assuming a level off at 3000ft before being cleared higher? Airbus manuals are doing my head in. Thanks.

sierra_mike
13th Feb 2017, 15:39
with 3000ft selected on the FCU while having 1600/3100 on your PERF TO page ACC ALT will automatically brought down to 3000ft and you'll receive "NEW ACC ALT-3000" msg on the MCDU.

Amadis of Gaul
13th Feb 2017, 16:04
Cool, learned something new.

Airbus Bloke
13th Feb 2017, 16:58
Mmmm....ok. Need to think about that. Although I've had this situation before I don't recall ever levelling at the initial cleared level. There has always been an early frequency change and a new cleared level.

safelife
13th Feb 2017, 17:05
That's not correct. Acceleration attitude will stay at 3100, but reaching 3000 ft you'll get ALT* if you didn't select a higher altitude by then.
The "new acceleration altitude" revision is applied only if there is a constraint, cross at 3000 ft, in the departure.

vilas
13th Feb 2017, 17:27
ALT* is what you get and SRS change signals acceleration.

J74
13th Feb 2017, 17:44
I'm not sure about what you wrote, and I'm not Bus driver,
but...
for what You asking for, Napd1 1500/3000 are heigh and you don't have to add the airfield elevation.
Then, what we use to do if your CDU report also the 1 EO heigh, at this time as per our Company policy for example minimum is 1000, we add the difference between this last and the MAFRA if higher than 1000, indicated in the T/O Performances.
hope this make sense..

b737air
13th Feb 2017, 18:07
I know this is not relating to the answer but isn't NADP 1 800/3000? Just not to confuse people around...

J74
13th Feb 2017, 18:19
my mistake!

NADP 1 is designed to meet close-in noise abatement objective. At minimum 800' AAE reduce to climb thrust, continue with V2 +10 to maximum 3000' AAE. Maintain positive climb, accelerate and retract flaps and slats on schedule.

NADP 2, is designed to meet distant noise abatement objective. At minimum 800' AAE maintain positive climb, accelerate and retract flaps and slats on schedule and set climb thrust (if not already done together with initial flap/slat retraction) and climb with Vzf +10 until reaching 3000' AAE.

Then others are ICAO A and Icao B.

But again I don't understand Airbus block, adding the Airfield elevation!

Citation2
13th Feb 2017, 19:06
If your FCU altitude is lower than the acceleration , as it is the case in your example , the FMA will show ALT blue on ground. A Typical FMA will be ALT ( blue) NAV ( blue) , that should draw your attention and awareness on ground.
No Climb blue on FMA.
The autoflight will switch from SRS to ALT* straight without going through CLB mode.

FlightDetent
13th Feb 2017, 19:19
^^ what he said.

Airbus Bloke
13th Feb 2017, 19:24
Thanks for all the replies. I've researched NADP1 to death. My company wants us to use 1500/3000 aal. Aal makes sense to me as somewhere like Geneva would have me reduce thrust at rotate if it was altitude. Try not to get too hung up on NADP1. I'm really just interested in the FMAs. Some of the above posts seem to have cleared it up.

Skyjob
13th Feb 2017, 21:46
Re altitude/height - as per J74:
Napd1 1500/3000 are heights and you don't have to add the airfield elevation

Re NADP1 1500 or 800:
800 is the minimum, 1500 chosen by many airlines for automatic thrust reduction on a two engine departure.

All values are subject to settings in electronics bay by engineers and can be modified for the aircraft in question.

sierra_mike
14th Feb 2017, 15:39
That's not correct. Acceleration attitude will stay at 3100, but reaching 3000 ft you'll get ALT* if you didn't select a higher altitude by then.
The "new acceleration altitude" revision is applied only if there is a constraint, cross at 3000 ft, in the departure.

you are totally right and i stand corrected, THR RED/ACC will only brought down to FCU ALT should FCU ALT be less than THR RED ALT

corrigin
20th Feb 2017, 17:17
If the FCU altitude is less than the acceleration altitude the FMA will show ALT blue on ground.

The auto flight will switch from SRS to ALT* straight without going through CLB mode.

First.officer
21st Feb 2017, 16:13
for what You asking for, Napd1 1500/3000 are height and you don't have to add the airfield elevation

ICAO Doc. 8168 quotes;

2.5 At no more than an altitude equivalent to 900 m (3 000 ft) above aerodrome elevation, while maintaining a
positive rate of climb, accelerate and retract flaps/slats on schedule.

Now, I've seen that if you included the airport elevation in the MCDU (for NADP1), the aircraft will indeed prompt (FMA) 'LVR CLB' at the appropriate point (SOP for us is 1,500ft above aerodrome elevation), with acceleration (FMA 'CLB' I think!) at 3,000ft above aerodrome elevation. The figures achieved in seeing the relevant FMA's (in relation to NADP1) are with the aerodrome elevation included, i.e. QNH set.

I appreciate that the doc. 8168 criteria are achieved after 800ft anyway, and airline SOP's are structured as the operator may desire, but it does mean that if you reduced thrust at 800ft (as entered on the MCDU, i.e. '800'), then the aircraft will ask for 'LVR CLB' at 800ft, but this would be with the QNH in all likelihood set on the altimeter sub-scale yes? so therefore would not be an NADP1 departure, as it needs to be at, or above 800ft aerodrome elevation?.

Now I know that any and most likely all operators don't use the '800ft' as an thrust reduction altitude (usually in all I've known, its >=1,000ft, or higher), but this hopefully means I've got the details correct here? I have observed this quite a few times now when carrying out NADP1 departures in the A320 series, so this is what it does....but I await a more informed correction/response if I'm wrong?

:ok: