Regulatory safeguards rely on people following them….
there are GPWSs that generate warnings (mode4) because of unsafe terrain clearance (between 10/30ft and 2450ft) when not in landing configuration, i.e. when in landing config = no warning , but you have below glideslope warning, excessive rate of descent, excessive terrain closure rate. But when you have got the enhanced one (EGPWS) a world wide terrain database gives you a terrain clearance floor (TCF) for each runway for which terrain data exist. On a 3 degree glidepath you are above that TCF.
The TCF function warns a premature descent below this floor, regardless of aircraft configuration.
Does bizjet GPWS work well enough for this purpose? I would think that, away from any IAP, all you get is the “five hundred” audio warning.
It depends on the setup. For example, ours does not call “five hundred” at all because in our operation this figure has no meaning. But an EGPWS (which would be mandatory equipment had this aircraft been on the german register) does give you a terrain warning in this situation. It is based on the radio altimeter and GPS position and altitude. If you come close to terrain beyond a certain distance from a runway, you will get a warning that cannot be cancelled other than by pulling a CB.
I don’t think an AOC operator can fly IFR to a non IAP airport.
Of course not. And double not in Germany as flying in IMC outside controlled airspace is verboten. Whatever your nationality, registration or type of operation might be.
Fog does not kill. Desire to land while immersed in fog DOES!
But when you have got the enhanced one (EGPWS) a world wide terrain database gives you a terrain clearance floor (TCF) for each runway for which terrain data exist.
I recall reading about “GPWS” from the Mt Erebus report. As far as actual terrain proximity detection goes, it was basically just the RADALT, which unsuprisingly sounded too late. I can’t see what else one could do. On a stabilised “long final” to a VFR runway you won’t get any other warning.
“EGPWS” has the GPS database – a primitive version is in my Garmin 496; the GNSx30 “certified” TAWS is supposedly better but Garmin don’t say how better. What would a Citation with EGPWS do if somebody descended down to say 300ft on a long final to a VFR airport? I just get the 500ft warning, 500ft AGL.
And double not in Germany as flying in IMC outside controlled airspace is verboten. Whatever your nationality, registration or type of operation might be.
Would it not be an accurate observation however that as a result of IFR in Class G being illegal, the German bizjet pilot community has a well developed practice called “IVFR” which is regularly practiced – see e.g. Egelsbach which is a VFR airport which is 80% owned by Netjets who of course never fly IFR 
There is only one universally legal way to fly to a VFR airport and that is to descend to the MSA and divert if not visual. That amounts to a DIY IAP with a 1000ft MDH. OTOH once you are visual (say having flown the ILS of a nearby airport) you can go down to 500ft AGL – is that true also in Germany?
There is only one universally legal way to fly to a VFR airport and that is to descend to the MSA and divert if not visual.
Illegal in Germany. You can legally only go to the dreaded MRVA, which – depending on the airspace structure – is somewhere between 1500 and 3000 feet AGL.
Peter, if you fly towards a mountain you get all sorts of warnings; it’s not just based on Rad Alt below the aircraft, but also the projected path and the terrain on that path .
if you fly towards a mountain you get all sorts of warnings;
How does that work on the old style GPWS? It has no terrain database.
Illegal in Germany. You can legally only go to the dreaded MRVA, which – depending on the airspace structure – is somewhere between 1500 and 3000 feet AGL.
Yes, but it is important to understand the correlation (or lack thereof) between what’s safe and what’s legal here.
Everytime there is a crash like this in Germany, the german IFR pilots cry out loud and moan, taking the opportunity to complain about the OCAS IFR ban in Germany. Well, this ban is bad, certainly, BUT:
Even if this ban didn’t exist, that would not have prevented this accident. The weather was just too bad!
I shudder when I think this one here. Look: yesterday’s fog in that area was very dense but also very shallow, with no clouds above. When this guy was at say 300 feet AGL (altitude at which any half-cautious pilot would, at the very latest, abort a DIY approach) he was probably still in the sunsine, with the layer still below him! End that’s when he started his “approach”. Shudder!
How does that work on the old style GPWS? It has no terrain database.
It does not. That is why after some accidents EGPWS was “invented” and made mandatory equipment for many types of aircraft.
What would a Citation with EGPWS do if somebody descended down to say 300ft on a long final to a VFR airport?
At 300ft it would probably do nothing yet. But if the projected flight path intersects with terrain too far away from a (known) runway, it will start giving warnings like “TERRAIN! TERRAIN! TOO LOW TERRAIN! PULL UP! PULL UP!” These get louder and more frequent the more urgent the necessary reaction becomes. On many installations, the audio is not fed into the intercom (where it could be muted) but to a (very loud!) loudspeaker. If you are visual with the terrain or otherwise know that a (false) terrain warning might be expected, e.g. when flying into valleys, you can inhibit the warnings with a button. But you can not inhibit the commands “PULL UP! PULL UP!” other than by pulling a CB. Therefore, producing a CFIT with an EGPWS equipped aircraft either requires defective instumentation or a deliberate act from the crew, either by ignoring the “PULL UP!” commands or py pulling the GPWS circuit breaker, both of which would immediately terminate your working contract with most commercial operators.
…which is a VFR airport which is 80% owned by Netjets who of course never fly IFR…
I know quite a few guys who fly for NetJets Europe and I can assure you, that they really don’t do illegal things. Absolutely never. If they can’t fly to Egelsbach legally, they don’t fly there. Never. Really!
There is only one universally legal way to fly to a VFR airport and that is to descend to the MSA and divert if not visual.
As boscomatico wrote: Radar will let you descend to MRVA while still being controlled by them and flying under instrument rules. If you have VFR conditions there (different criteria, depending on the class of airspace, E, F, C or D) you either cancel IFR and proceed visually to your destination or you divert. The other option is to fly an instrument approach to a nearby airfield and proceed visually once you meet VFR or special VFR criteria and are able to maintain your minimum altitude (500/1000/2000ft depending where you are). Special VFR usually applies when your cloudbreaking alternate has a control zone. If ATC permits (special regulations inside control zones sometimes forbid continuation of the flight under VFR) you can cancel IFR and proceed visually.
