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Is there ever any excuse for being caught out by fog, and what would you do?

Peter wrote:

I think I would navigate (somehow) to some distance offshore and then descend, slowly… the raft is always carried.

That is never necessary. In 47 years of flying, I have never seen a landscape of fog without some holes somewhere, either hilltops or downwind from industrial areas or whatever. You will always be able to find a field in the clear.

But in the South of England, Biggin, Compton and Dunkeswell are the places to find out about before you take drastic action. Southend is also often clear when everyone else is out.

EGKB Biggin Hill

Reflecting a similar view from another thread, if fog is forecast or likely you really want to get as much fuel in as is safe. That is actually your best defence mechanism.

Last Edited by JasonC at 10 Oct 21:25
EGTK Oxford

Peter wrote:

But surely this is not realistic. Would you get zero-zero conditions and a loss of GPS

That’s exactly what happened to me once. Location is Central Europe near the Alps. Went for a local flight on a gorgeous autumn day an hour or so before sunset. Had planned to go a bit further, but noticed fog forming in shallow depressions below me, so decided to turn back. Approaching a VRP to the big(ish) airport I was flying to, I noticed that the location was off by about 5 miles on the GPS. I know this area extremely well both on the ground and in the air, so had no problem navigating, but this was disconcerting nonetheless. By now, the fog started to cover increasing areas below me and I was starting to get worried – all the nearby fields would have been fogged in by now and the nearest I could think of that was prob90 clear was about an hour’s flight away. Another argument for always carrying enough fuel….. which I had, no worries there. Anyway, I asked the tower to put all lights on high and sure enough – there it was: an island in a white sea of fog. While landing, the far end of the runway started to be consumed by the white and wafty stuff. Taxiing in was a challenge… I guess the black asphalt of the main runway stayed warm just that little bit longer to keep that window open. ILAFFT.

PS: we never figured out what the GPS issue was

JasonC wrote:

I would look for a long, ILS-equipped runway, descend fully configured on the GS and at about 100 feet start to pull power back and raise the nose slightly to ensure touchdown on the mains. Just stay on the localiser and don’t stall.

To follow the GS below minima may well cause rather unwanted results. CAT II/III approaches rely on additional sensor input such as RA. Probably the best solution is indeed to fly to the minimum and then keep the rate of descent you had on the glide and keep the loc centered with a nose up attitude and wait for it. Also: check RVR on the opposite side, often enough the ILS side of the runway is worse than the opposite end.

Obviously even better don’t get into this situation in the first place, take enough fuel you can divert with, even if that means quite a bit of reserve.

Fog is notoriously difficult to forecast and fools the best in the trade. 2 kts more or less wind can make the difference between CAT IIIC and CAT I. So whenever there is a possibility of fog, I’d plan with closed destination and define two bullet proof alternates.

LSZH, Switzerland

Timothy wrote:

Firstly on the “is there any excuse” element of the question, the answer is yes. I have encountered it twice where the whole of Southern England was covered in completely unforecast thick fog.
You can always encounter totally unexpected weather. If you want to cover all eventualities, then you can’t fly at all.

Not really about fog, but an illustration of how very difficult weather forecasting can be. I once (in the 1980s) made a short VFR flight after dark on a beautiful cold winter evening. There was a stable high-pressure situation with severe CAVOK (essentially unlimited visibility). I called the meteorologist and he assured me the weather would stay CAVOK and that in particular there would be no fog.

An hour or two later, in the air, things suddenly didn’t “look right” at the horizon. I turned on the landing light and saw — snow. I could barely see ground lights 4 km away, so I estimated the MET visibility to be less than 3000 m. I managed to return to the airport and land.

I called the met office and asked “what the ****”. They were just as surprised as I was. It turned out the ice had broken up in part of the Baltic Sea, some 70 km away. CBs had instantly formed over the water and drifted in over land with snow showers. How do you forecast that?

Last Edited by Airborne_Again at 11 Oct 07:37
ESKC (Uppsala/Sundbro), Sweden

This is why I always have a copy of the Brize Norton EGVN approach plates in my flight bag. I figure it is the longest, widest runway around in my area of the world (Gloucester/Oxford), and with great medical care, emergency services and controllers, and not busy with CAT. You could fly the ILS there to below minimums and then descend very very slowly in the flare following the localiser. The runway is 3,050m long and over 60m wide.

Upper Harford, United Kingdom

Buckerfan wrote:

The runway is 3,050m long and over 60m wide.

Apparently landing in a Pitts in this sea of tarmac is … interesting!

Enstone (EGTN), Oxford (EGTK)

Airborne_Again wrote:

I called the met office and asked “what the ****”. They were just as surprised as I was. It turned out the ice had broken up in part of the Baltic Sea, some 70 km away. CBs had instantly formed over the water and drifted in over land with snow showers. How do you forecast that?

Those weather systems are highly localized in time and space, so extra fuel as JasonC suggested is your best strategy (if you orbit & land 30min it could clear & smooth)
The same applies to fog it will clear up in 1h (or may take longer), for radiation fog, you may also argue of flying west/east depending on sunset/sunrise but you may need at least 2h of fuel around for that to take effect

EGSX, United Kingdom

WWII factory test flights were not often cancelled due weather and in “Sigh for a Merlin” Alex Henshaw says that he would look for the steam from the Cannock power station punching up through the fog to get his bearings for Castle Bromwich. Of course airfields were big open fields with no specific runways then.

Oh. The coal fired power stations are closed now. Perhaps the wake from the wind turbines will suffice? Ah. there’s no wind..

EGBW / KPRC, United Kingdom

GPS and autopilot specific discussion about what happens below the DH (ILS or LPV) has been moved to an existing thread

Alex Henshaw says that he would look for the steam from the Cannock power station punching up through the fog to get his bearings for Castle Bromwich. Of course airfields were big open fields with no specific runways then.

How did he do it?

Did he route to overhead the power station and then fly a (roughly wind adjusted) heading i.e. a track, and treated that as the lateral guidance for a timed descent to the runway? That should be reasonably accurate, especially as you can tell the wind from the way the smoke is bent.

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Shoreham EGKA, United Kingdom
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