A third way is “Everyone knows that my plane can indicate 250ft off so I frequently ask mode C readout from ATC and act accordingly”
Yeah, but you aren’t going to be doing that with any ATC unit which does the LTMA, for example.
I do this with Solent when doing the scenic flight around the IOW (because the altitude margins are really tight there) and get it on the mp3 recorder.
Xtophe wrote:
A third way is “Everyone knows that my plane can indicate 250ft off so I frequently ask mode C readout from ATC and act accordingly”
Which is what happens by default when talking to an FIS in continental Europe – They tell you “identified” and if your altitude they see isnt what you told them on first contact they ask you to confirm – at least thats what it seems like to me in my experience.
Regards, SD..
Malibuflyer wrote:
“Everyone knows that my plane can indicate 250ft off so I should stay aways at least 250ft indicated from every airspace so that I’m on the safe side” …
I think ATC also know that and should add +250ft on CAS base to be on the safe side (and 2.5nm lateral), pilot should take +250ft (and 2.5nm lateral) to be on the safe side, what is problematic is that lot of UK SE airspace is not designed to even take those margins: IFR MSA inside CTA/TMA CAS, 2000ft agl ATZ inside CAS, 5nm between two lateral CTR/CTA bits, it’s the jungle baby, you will have to fly up to LPV lateral/vertical accuracy OCAS
I am sure putting all CTA/TMA CAS 2000ft agl above heighest obstacle will solve load of these problems: neither airliners fly that low away from CTR (it’s bloody dangerous if you think about it) and most “ignorant VFR traffic” will be stuck at 2000ft agl by default as we know they don’t know how to use the mixture above that 
Inside CAS flying accuracy is way more relaxed, ATC will allow me to deviate +/-200ft and +/-2nm on transponder level and radar blips as they understand there tolerances to vectoring and let down and PIC flying accuracy is still human, it’s called lateral RNAV2/RNAV1 and flight level tolerances in CAS, why my OCAS flying has to be tighter than that?
PS: only “human pilots” will understand what I write above, “machine pilots” don’t have the intelligence to cope with such levels of imperfection
skydriller wrote:
They tell you “identified” and if your altitude they see isnt what you told them on first contact they ask you to confirm – at least thats what it seems like to me in my experience.
Yes — that’s why we’re supposed to give our level to ATC even though we have mode C/S transponders.
Off_Field wrote:
I know that it’s a common error on my type (the pitot static are very close) that leads to different altimeter readings at speed. I think I checked it a long time ago on a long runway, but it’s worth double checking. I never thought of relating it to the bust ’em policy.
Because it doesn’t matter. What can get you into trouble is if your altimeter and transponder differ.
skydriller wrote:
Which is what happens by default when talking to an FIS in continental Europe – They tell you “identified” and if your altitude they see isnt what you told them on first contact they ask you to confirm – at least thats what it seems like to me in my experience.
Yes but within their +/- 200ft tolerance. So not so useful if you then plan to fly just under controlled airspace within said tolerance. If you ask for a readout you know exactly where you stand.
kwlf wrote:
I don’t know how common that is, but it isn’t as if the point wasn’t covered. Perhaps mode A transponders are being replaced with C/S transponders without them being connected up in the interests of expedience, as this would involve tapping into the static system and all the messiness and risks of screwing something up that entails.
Well that start to be a bit far fetch. I know some avionics installer have bad reputation but that going quite far.
I find the idea that nobody looks at the effects of yaw on static error alarming… unless that is only for VFR types in which case this is a non-issue. Can you really certify an aircraft for IFR flight without measuring such things?
But it doesn’t affect infrigement.
I guess it must be specified somewhere in the the certification standards for multi engine a/c. So that the error is acceptable in the engine out case.
Because it doesn’t matter. What can get you into trouble is if your altimeter and transponder differ.
It does matter insofar as the purpose of avoiding controlled airspace is to reduce the potential for an accident. Avoidance of being busted is only secondary.
In airliners, I don’t think they would worry much about effect of yaw on static ports and the reported altitude when they lose one engine, I would say good luck with staying inside the whole CTR/CTA let alone assigned level/heading (reminds me when an international airport called it’s nearby gliding club to stop all gliding operations as they had “one incoming” )
