This is interesting
There is some really interesting stuff in there, especially the obstacle clearance warning system which ATC at CDG has.
Applicable to us in GA for sure.
Applicable to us in GA for sure
Do you know that many people in SEP who fly L/VNAV using BARO with QNH?
On 3D guidance by GA: ILS or LPV if one crashes due to QNH setting it’s usually dead right on the runway touchdown with “stable” -500fpm at 3 deg (it’s not bad situation to be honest even in zero/zero weather), even cheating with SBAS to use +V will save the show if some ILS or LPV is published
It could happen on 2D using ADF, LOC, VOR with or without DME? those who fly these in SEP are just hopeless, pathetic
It could happen in any GA system if you mis-set the altimeter and there is IMC below the DH.
You will bust DA fine, even in zero & zero weather following LPV & ILS you hit runway touchdown point not some hill 3nm away?
Crashing on runway TDZ using 3D guidance at -500fpm is without flare is “strong” hard landing
I think most airlines should invest in getting LPV & SBAS fitted to cover cases when RV+ILS is U/S? it’s getting scary all of this freestyle flying using BARO VNAV, crazy 2D VOR NPA with large offsets or even worse handflying B737 on NDB with stopwatch
I don’t understand what you are saying.
If you mis-set the altimeter and there is IMC all the way to the ground, then you can hit the ground, obviously. With a 200ft ILS, you need a mis-setting of > 7 millibars to achieve that.
Peter wrote:
I don’t understand what you are saying.If you mis-set the altimeter and there is IMC all the way to the ground, then you can hit the ground, obviously. With a 200ft ILS, you need a mis-setting of > 7 millibars to achieve that.
Peter, I think he meant that unlike with Baro-VNAV, other methods (LNAV/non-Baro VNAV, LPV as well) do not rely on Baro setting and will show you you possition in space using just GPS signals.
You always hit runway touchdown point when you keep flying LPV guidance bellow DA, try it next time: at 6ft agl you will be over runway centerline ready for the flare 
these guys were about to crash in hill that is nowhere near the runway threshold
I think you are not visualising it correctly, -200ft bellow DA you are on paved runway touchdown point further on the glide slop of ILS & LPV not on some hill 1nm away
While ago for fun, I let my auto-pilot fly LPV down to 10ft, looks like it guarantee survivable outcomes, on ILS, less so near LOC antenna but still on the runway
There is no LPV feature in A320. If you screw up and set wrong qnh you end up being too high or too low all the way on your profile. Altitude vs checks will be looking ok but your true altitude will be wrong. On a very flat terrain there is a chance that you catch your mistake by looking at your radio altimeter but if there are hills it doesn’t work. There is no protection in 320 against this mistake. It’s like doing an LNAV with GNS430 non waas – wrong qnh – wrong profile.
ILS or LPV are immune to this problem. You are always on correct descend profile, just possibly busting the minimums.
Peter wrote:
It could happen in any GA system if you mis-set the altimeter and there is IMC below the DH.
Peter wrote:
I don’t understand what you are saying.If you mis-set the altimeter and there is IMC all the way to the ground, then you can hit the ground, obviously. With a 200ft ILS, you need a mis-setting of > 7 millibars to achieve that.
I demonstrated this to a student the other day on a G6 SR20 which can do BARO-VNAV. I switched off EGNOS/WAAS to get the approach downgraded to LNAV/VNAV and then changed the baro setting. The GP indicator moved accordingly.
Basically an the ILS / LPV glide slope/path will provide a fixed plane towards the GS antenna (by radio beam(s)) or the TDZ elevation (calculated). A wrong altimeter setting might make you scratch your head because DME values would not meet the corresponding altitude values, but staying on glide would lead you to TDZ regardlessly.
A BARO-VNAV with the altimeter setting too high will make you fly a perfect 3° GP with all altitudes corresponding to distance. But you´ll be below the intended GP, going to a place in front of the TDZ.
ILS or LPV are immune to this problem.
This is the key point.
ILS/LPV are „fixed beams“ ending at the runway while temperature and pressure is irrelevant for them. The source is a radio signal „reading the beam“.
OTOH any approach flown with the altimeter and thus using a barometric source… wrong QNH, low temperature, low pressure etc… will lead to problems.
