RVSM EUR

[fernando]

How accurate has to be the cruising in the RVSM?

I believe many navigation systems do cruise at +/- 100 ft so as to have a smoother ride.

Will you get a warning for FL deviation?

Thanks

[Ahh-40612]

Not sure of the parameters but it seems that the kit on the Embraer 135's and 145's isn't up to the job as their RVSM compliant status has been revoked.
Any pilots/techies care to let us know exactly what's wrong.
Are we all to be suspended by SRG for 6 months worth of separation losses???#

[eyeinthesky]

I'm not a techie either, but I think 100 ft will be far too much deviation. That gives you only 800 ft in a worst case situation. I think it will have to be far less than that.

[SWMAE03]

Not being a techie myself, either, I have no idea if this is accurate, but, doesn't secondary radar interrogate the transponer which get's it's altitude reading from the altimeter? If so, and the altimeter is inaccurate, what on earth can ATC do to ensure a minimum of 1000ft separation?

Just a thought.

[ADIS5000]

Guys,
You're forgetting that the verified Mode 'C'limit is +/- 200ft. As I recall, the 1000ft for standard separation is purely to ensure that with one aircraft reading +200ft 'C' and an aircraft above it reading -200ft 'C'(ie the maximum permissable discrepancies) then a 'safe' margin of >500ft is kept. I much prefer "Negative RVSM"!!

Cheers,
ADIS

[NextLeftAndCallGround]

SWMAE03, encoding altimeters normally use a separate 'altimeter' which is always set to 1013.25mb. Conversion to altitude on a radar display is done by the display processors. Although I don't know what it is, I'm sure that there is an accuracy requirement specified. As some of the other posts have mentioned ATC procedures allow a bit of 'slack'. If you've listened to ATC radar frequencies (particularly departure frequencies) you'll have controllers asking pilots to report their level or passing level. If the radar readout is within 200 ft of what the pilot says all is well. If after trying again (ideally when the aircraft is in level flight) the readout is still not within 200 ft the pilot should be told to switch off the mode C (altitude) reporting.

[SWMAE03]

ADIS,NextLeft,

Thanks for that, clears it up for me.

[fernando]

What I am talking about has nothing to do with the Xponder.

The aircraft I fly has two modes for cruising, one does a very good job on maintaining the FL and Mach Number but it needs alot of throttle adjustment
the other mode allows the aircraft to cruise at FL +/- 100 ft requiring less throttle movement hence less fuel burn.

What I will like to know is how accurate has to be the level keeping?

P.S. Does PPRUNE has a Regulator Forum?

[PPRuNe Radar]

For level occupancy, the aircraft has to fly at +/- 200 feet accuracy.

However, for system performance the RVSM MASPS require that the aircraft type Altimetry System Error, for the basic flight envelope (JAA TGL6 §7.3) should meet the following:

(a) At the point in the envelope where the mean ASE reaches its largest absolute value that value should not exceed 25 m (80 ft);

(b) At the point in the envelope where absolute mean ASE plus three standard deviations of ASE reaches its largest absolute value, the absolute value should not exceed 60 m (200 ft).

Full information here:

http://www.eur-rvsm.com/

[Techman]

One thing I was wondering about is, when entering British airspace the controller have on several occasions asked wether or not we were RVSM equipped, we answered no because we had no information from our company that we were. The controller then said that according to his info we were??.

Another operator was asked the same, and answered yes. The controller then said according to my info you are not.

But who's info is it that is "legally binding" so to speak. I suspect it is the controllers, but if that is the case why ask?.

[ZIP250]

On the legally binding bit it is quite clear. Apart from E135 and E145 aircraft where we have a specific instruction to treat them as non compliant regardless of what the pilot says, the pilot's word is law. If he says he is compliant then we use RVSM separations after changing things in NAS to stop the alerts going off and vice versa.

Also if the flight plan says you are compliant then we assume you are unless you tell us otherwise. The only time we ask your status is if we think that our data is inaccurate (eg a transatlantic flight which has filed RVN.

Regards

Z

[ 23 October 2001: Message edited by: ZIP250 ]

[Techman]

Well, we were actually below 290 and with the UK as destination, thats why it struck us as a bit odd.

Anyway, thanks for the reply Zip.

[ 23 October 2001: Message edited by: Techman ]

[Bigears]

Techman, maybe he was thinking of asking you to take a higher level to resolve a traffic problem, but had a 'gut feeling' that despite your company filing you as compliant, you weren't. Just a thought/guess.