How would you know that? The only way for you would be to go to the satellite status page on your Garmin unit and see if you can see WAAS satellites plus you should see a status like "3D DIFF NAV", plus letters "D" under individual satellite bars meaning that differential signal is being applied. Your manual would tell you what to look for. Without those signs there is no WAAS, just normal GPS.

Whether your Garmin 430W is compatible with European EGNOS system (which is much closer) - it is a separate question.

One difference between the 430 and 430W is the update rate. The 430W updates once per second, the 430 once per 5 seconds. Also (maybe) a better GPS receiver suite.

@olasek...

My apologies. I meant the GPS worked well. Misinterpreted the usage of the 430 WAAS.

But either ways when a flight is suppose to fly VFR only, and it is not, even having WAAS can be dangerous because of lack of such procedures.

And agreed that WAAS is useless but the 430 garmin and 530 Garmin with weather radar is much better to have in aircraft and increases situational awareness then not having those equipment on board.

WAAS is only an augmentation system. A other words a precision addition if you like. You need FIRST to have the GNSS set up in place ( like PBN routes and APP, etc.) drawn up, certified and published . Then you can augment.

Last to have PBN you need procedures, ( not too expensive to make ) and the certified equipment on board. That one can be quite expensive if we talk retrofit.

For Nepal, you have no procedures and no equipment. You cannot do PBN/GNSS with a handeld Garmin taped to the dashboard . Most of the airlines ( with perhaps the exception of Buddah) have not really money for this. I am not even talking of the extra training that would be required .

Maybe when the tourists will stop boarding and start asking questions, then perhaps, we will see this implemented.
But as long as ticket price is low and the tourists consider jumping in a old Do228 in marginal weather in mountains part of the adventure, the need to change is relative.