Jeppesen approach plates vs AIP plates

Airborne_Again wrote:

I didn’t even know that you’re still allowed to use ILS/VOR equipment with 100 kHz channel spacing

Military aircraft? they still drive through civilian navs & radios using 100khz VLOC & 50khz COM with no FM immunity and zero spacing compliance?

I don’t think they are equipped for 8.33khz & 50khz COM+NAV

Airborne_Again wrote:

If it is less – which is not uncommon for ILS approaches but less so for other types – you have to increase the OCA with the difference between the OCH and the system minimum. This involves some arithmetic which is simple but you still probably want to do before actually flying the approach.

I thought one just takes the system minimum for your DH/MDH which requires no arithmetic and gives the same result?

I thought one just takes the system minimum for your DH/MDH which requires no arithmetic and gives the same result?

Don’t you need OCH < system minima?

Even better: add 50ft to OCH with rounding to 50ft above that gets you one DH that should work for any system minima out there: Cat-I PA, APV, NPA

Realistically, in CatA aircraft you can’t have:

• OCH < 140ft for Cat-I ILS or LPV
• OCH < 190ft for VLOC/DME
• OCH < 240ft for NDB
• OCH < 290ft for SRA RTR2nm

If there are real life examples, I am happy to have a look

System minima and OCH are highly correlated above 200ft…you can scatter plot them for every AIP plate out there and regress

The two start to diverge a lot under 200ft DH where people start to make complex arithmetics, at 10ft precision, you need PhD in this stuff

Ibra wrote:

Don’t you need OCH < system minima?

The context of the quote was “if it [the OCH] is less [than system minima]”.

Airborne_Again wrote:

then your DA will be 398 feet and the OCH 200 feet

I mean DH 200 feet, of course.

lionel wrote:

I thought one just takes the system minimum for your DH/MDH which requires no arithmetic and gives the same result?

For the (M)DH, yes. But you fly using the (M)DA so you do need to do some arithmetic. Either you do it the way I described or alternatively you look up the threshold elevation and add the system minimum to it. The reason I prefer the way I described is that I only have to look at the minimas on the AIP plate. The threshold elevation is written at the top of the plate and on always in exactly the same spot. Compare the Croatian and Czech plates in Emir’s posts above.

Ibra wrote:

Realistically, in CatA aircraft you can’t have:

OCH < 140ft for Cat-I ILS or LPV
OCH < 190ft for VLOC/DME
OCH < 240ft for NDB
OCH < 290ft for SRA RTR2nm

Actually the OCH can theoretically be as low as 130 ft for Cat I approaches, but no lower than 246 feet in all the other cases. (Except for the unusual case of 2D approaches without a FAF where it can be no lower than 295 feet.)

Is Skydemon suitable for IFR?

I’ve been using SkyDemon for my VFR flights and Jeppesen for my IFR flights for several years. I want to get away from Jeppesen and was considering ForeFlight, but their prices are exorbitant for the 3-4 SP IFR flights I do in a year. So I am considering flying IFR with SkyDemon and the charts it offers: from the AIP and some custom ones. Plus a PDF backup of the AIP charts that I get from autorouter.aero.

What is your opinion? If I understand correctly, it would be completely legal. What about the practical side, anyone with experience?

Absolutely. The combination of autorouter and Skydemon is great. I have been using it for 10 years now.

Regarding the AIP charts, lots of controversy. Of course, you need to look at the procedures before flight to make sure you have the information you might need, but then you should do that anyway. Of course the layout the user-friendliness of the charts across European countries vary, but at least in central Europe, they are mostly ok. A few points:

• you need to calculate approach minima yourself. In most cases, this is absolutely trivial
• generally speaking, in many cases, bits of information are spread across several pages, whereas Jeppesen cleverly puts things onto one page
• in FR, the plates are not found under „charts“, but in the AD file, which is not so nice
• In NL, the SID plates don‘t show the textual descriptions of the procedure, you have to check the AD doc for that
• in some other country (forgot which one) the plates are missing the radio frequencies, you have to check the AD doc for those
• general readability and user-friendliness on the Italian charts is so-so
• a few other nitty gritty details, which, if undiscovered, could theoretically cost you your life one day

Vladimir wrote:

So I am considering flying IFR with SkyDemon and the charts it offers: from the AIP and some custom ones. Plus a PDF backup of the AIP charts that I get from autorouter.aero.

What is your opinion? If I understand correctly, it would be completely legal. What about the practical side, anyone with experience?

That’s what I use for flying. Please keep in mind, that in SkyDemon you could just download the whole AIP for a specific countries and it will be available offline. I do it before every flight just in case and if I need to divert, I have all info at hand. Again, no Jepp.

IR schools quite often object, as they have access to “free” Jepp anyway (they somehow have to buy those), but unofficially intrsuctors all say it is OK and will work.
And yes, it is legal. More than that – the official guidance for the UK IR test, for example, says that any 3rd party data provider have to verified against official publication, some examiners take it to the extreme. :) Yes, I understand that you’ve already got your ratings, but that was just to illustrate that it is legal.