Noise sensitive departures
 

Hi guys,

The company that I am working for has been recently fine quite frequently due to noise violations at french airports. This was no news, however since the biginning of the year we moved from one ocasional to about 3 per month.
This is becomming expensive as each fine has a 20.000€ cost.

Do your companies Have special procedures for noise sensitive departures?
(our SOPs do not include any special procedures to adopt, however we always try to max flex our eparture performance and to reort any SID deviations for whatever reason on the captain's report).

Thanks in advance for the inputs,

What are you being accused of ?

Exceeding the prescribed dB value, or straying from the noise abatement route ?

Where are these limits laid down, what are they, and what evidence are you being supplied with in relation to your alleged infringement ?

Are you using NADP-1 when you should use NADP-2 or vice versa?

What changed that led to noise violations becoming frequent instead of occasional?

My company prescribes what NADP is to be used on every flightplan.

Well,

We are mainly getting fined by lateral noise reduction route exceedance, however we still do it the same way as before, just follow the FD guidance.
This has not changed.

Although some SIDs have had minor modifications, most of them still remain basically the same, as do our aircraft, however we are getting more and more reports.

Each report is detailed with a lateral ground mapping of the aircraft's real track, compared to the prescribed noise abatement route. The company checks this data against data removed from the aircraft and compares it.

We mainly use NADP 2, however, it might depend on the SID and direction of departure in relation to route direction.

Does anyone use de-rated climb modes as SOPs for noise abatement?


Either the noise pickups are becoming more sensitive, or the tracks are becoming thinner.

Used to get noise violations at LHR, (B747-400), procedure became Lnav, Vnav, Auto Pilot at 400', violations stopped, manual tracking never as accurate as the auto-pilot! (The usual 'aces' will disagree;)). Reduced thrust or full thrust? Depends on aircraft/airfield etc. sometimes full thrust will get you up, up and away reducing your noise signature, what is the company SOP?

Marlboro,

This is certainly interesting, especially if you havent changed anything on DEP.

Do you know if other airlines have the same experience?

In monitoring the wake turbulence, I have noted that the marine and inversion layers have an effect on noise transfer. The layers will reflect and deflect noise as well as the wake vortex.

If the violations are happening mostly at dusk, this may be from the marine/invection layer rises this will cause noise to bounce off and down, amplifying the noise in certain directions.
Prevailing winds due to invection will also direct/concentrate noise to areas outside of the normal flight noise contours...

Would be interesting to see the specifics, as currently, we are looking at methods to purposely direct noise with winds and invection/inversion layering.

Parabellum, you still in VIC area?

So is there a mismatch between where you think the aircraft flew, and where the airport says it went ?

Is your FMS GPS-driven or inertial-driven ?

That doesnt make sense. Unless you have a stand alone unit, the GPS input is through the IRU.

OK, I'll rephrase that for the pedants: Is the navigational data available to your FMS of an accuracy comparable to a GPS source, or does it originate from an inertial-based system, thereby being both less accurate and subject to drift ?

The object of the question being to establish whether the data that the OP downloads from his aircraft is of a sufficient accuracy to challenge, if necessary, the authorities' track-keeping data, which will be radar-based.

I think what he is trying to say, does the aircraft have GPS or does it rely on DME/DME updates? If it updates from DME and an intersection departure is routinely used (without t/o shift input) the position update on the runway could be at the wrong point. If the initial turn occurs before DME updating can take hold, you may be up to 1km out...

If you have GPS fitted, please disregard this point!

Marlboro 2002

Can you be more specific eg can you tell us the airport(s) and whether these are noise or track violations. €20,000 is a hefty fine!

For example at LHR noise infringements, ie where an aircraft exceeded a specified noise level, were fined and the monies given to local charities. At least that's how it worked in the 90s.

Track violations where the aircraft did not follow the SID were reported to the airlines but no fines imposed. The biggest problems were on departures with large turns as the effects of drift and speed etc made for a much wider spread in tracks. Straight(ish) SIDs eg Compton westerly departure were very good at track keeping.

regards

BBK

A quick look at the ACNUSA website would suggest that those relatively high €20K fines are mostly imposed for failure to keep within the departure VPE (Volume de Protection Environnementale) airspace (roughly equivalent to an NPR swathe) at CDG.

The French AIP, unlike its UK counterpart, actually gives the coordinates of the VPE boundaries, so given sufficiently accurate nav data from the aircraft's systems, it would be relatively easy to verify whether an alleged infringement had occurred or not.

It would be good to get more specifics, but what appears odd is that according to Marlboro, their ops havent changed, they just started getting fined....

For the most part, these systems use the ADSB to track the ac....Is there a webtrak set up for this airport in question? If there is, that would be good to look at first, as that system saves historical data.

From the ac system, the Flight Data Acquisition Unit (FDAU) primarily sends the data to the flight recorder, but most have a secondary bus for output. The FDAU can provide data and predefined reports to the cockpit printer, directly to Aircraft Communications Addressing and Reporting System (ACARS) for transmittal to the ground, or to a Quick Access Recorder (QAR) for recording and/or storage of raw flight data.

This is used by the FOQA, so if you have a program like that set up, the data cab be derived from that as well.

That doesn't make sense - it would imply that aircraft not fitted with ADS-B aren't going to be detected when they go off-track, which is clearly not the case. Ditto aircraft which send ADS-B with a low NUC_P.

The airport NTK systems that I've encountered use processed radar recordings to monitor track-keeping. That way, they capture 100% of flights.

They can use all of the above, depending on the level the airport asked for...
(it appears the configurations that NATS uses include everything)
When one compares ADSB data direct with WebTrak, you can spot missing flights on WebTrack...other Countries, with more developed airspace systems and ADSB requirements, can just use that data for WebTrak...(just messing with you)

It is nice to see the full data package that the NATS system provides....

No, it doesn't. As it happens, I was including ANOMS in my reference to "airport NTK systems that I've encountered".

If you look again at that diagram, the part we're interested in for track monitoring is the box labelled "t,x,y,h" (i.e. aircraft's 3D position plus time). Follow that link upstream and it ends at the box labelled "Radar". No ADS-B.

I agree with your point about WebTrak missing flights, though, in fact a couple of years ago the LHR system went through a phase where it used to go sick at weekends and lose dozens of flights. On that occasion I got involved in helping out by providing independently-captured ADS-B data to assist BAA/NATS to troubleshoot the problem.

It still drops flights from time to time, though.

I see that ADSB, and probably rightly so, since it is not req'd, is not included in the NATS version..

The FIS can cause the flights to drops off, with the bundled or whatever you guys call a flight sold by several airlines.

So, IF the airport in France has coverage, that would be an easy way to check the tracks for compliance...

If you mean coverage by one of the enthusiast ADS-B networks, that wouldn't really help much as AFAIK they don't record the NUC_P parameter that accompanies the ADS-B airborne position transmission, so there is no way of knowing how accurate the track is.

The best outcome would be if GPS-originated data could be downloaded from the aircraft itself. That would allow the authorities' tracks to be verified.

So back to the OP ...

No, I meant if the airport had WebTrak...

Not sure how long the data is stored before over-write....or if they even have the external recording set up...

guess the op will need to sort that out..