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#1180220
Those who also see me waffling on Facebook will already know that myself, my flying partner and Rhubarb The X'Air ended up having an off-airfield landing yesterday after getting caught out by the weather.

Perhaps less discussed than post-engine failure arrivals into fields is the precautionary landing under power in that situation, yet we weren't in fact the only aircraft from our strip to need to do it yesterday, from two different departure points yet ended up close together in different farmers fields.

Hurt to nothing but pride (and bird doings on the aircraft which had to spend a night without her covers), we flew back today, but the other chap's awaiting a field trim before he can get out again.

I'm still trying to figure out what it was in the forecast that all three of us missed to find ourselves there. Amazing the data there is to pull through!

The TAF I got before leaving for the strip at midday was
EGFF 291102Z 2912/3012 29010KT 9999 SCT040
TEMPO 2915/2918 8000 BKN008
BECMG 2918/2921 8000 BKN006
PROB30 TEMPO 3000/3006 4000 BR BKN004


I frowned slightly over the "TEMPO 8000 BKN008" but the 'out the window' looked good, we were in no hurry and had no especial need to commit to a particular route and could dodge any nastiness. The 215 as far as I could see, concurred with much use of "Isolated" and "On Hillslopes" and "Coastal". Our strip's both and there was some cloud clinging to the hilltop but it was clearly visible and easy to dodge and once we were up we were past it and under blue skies in minutes.

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215

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Cloud along the ridge

With hindsight I completely failed to register the BECMG which proved to indeed become important. Because it was 1 o'clock we planned to fly - who cared what happened coming on 7...

Except we didn't actually leave until 4, didn't check the updated NOTAM at our destination, another little strip Cemais Commander, half hour away because the sky and conditions looked to the eye unchanged.

If we had looked again, we'd have seen this:
EGFF 291659Z 2918/3018 28015KT 9999 SCT008 BKN012
TEMPO 2918/2921 6000 BKN006
PROB40 TEMPO 2918/3006 4000 BR BKN004
PROB30 TEMPO 2921/3006 0400 FG BKN001


I don't know if we'd have believed it, sitting as we were in t-shirts and wishing we'd brought more water, but perhaps we'd have thought more about what was physically happening to change things. Maybe thought in particular about the little clouds we'd had to dodge above the hills north of the strip and wondered what was happening to them given this new forecast.

But we didn't and we set off home, taking off at around five past six (1705Z). It looked, if anything better than the trip up and we headed straight over the hills at first but turned south down the Rhymney valley when we crossed it and it looked like there was cloud ahead over the higher ground. We weren't down in valley to stay under the cloud - but because the cloud was overhead the hills but not overhead the valley. Weather deteriorated steadily but we were sure it'd break up once past the high ground and on reaching the lower lying ground around the M4. (It has before... Often! Another trap...)

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Llandegfedd on direct route

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Ystrad Mynach - still sort of okay-not-brill but we want to go to the top left of the pic and that's not...

By Caerphilly we were stuck ahead. We discussed fuel - still enough to go back to Cemais - and the fact the cloud broke up to the east and we may be able to get around it that way and reach the motorway, we also climbed to have a look and decided to give that a go.

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Caerphilly - no passing it

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Round the edge? Maybe...

No photos from there on because all of a sudden navigating and lookout became very important very quickly as it became apparent that it wasn't, after all something we could go around and in fact was getting worse around us right here as we flew instead of improving over the lower ground as we'd thought it would. We weren't flying into it - it was forming around us and we were already on the limits of both legality and common sense

A fairly uncomfortable 8 minutes later we reached the outskirts of Bridgend where the motorway cuts back towards the hills for a spell. and that little extra height was enough to change the vis from 'manageable at this silly slow speed and and height to 'nope no way this is daft.'

I came to the conclusion slightly behind my more microlight-focussed flying partner that we (and for 'we' read 'he' because he's the one with all the time on the aircraft!) were plain and simply going to have to land somewhere and in a state of still half disbelief I remember saying "Okay if we're really doing this, I've got a good field".

It was on my side of the aircraft and the one I'd been eyeballing in case of sudden silence up front and it really was the sort the textbook always has and real life obliges with less often. Open approaches, up on a slight ridge, recently cut silage, farm itself a field away in case we needed help.

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Field on the right of the strut (taken the next day after leaving)

Given the speed with which things were deteriorating we were half in favour of landing at once, but I argued for a low pass for at least a looksee - peering down past the tyres at the grass with acute interest!

In fact the landing was as gentle as could be, a longer than average rollout - in amidst everything else we'd landed with a tailwind albeit uphill.

It was half past six and by the time we'd found someone, explained (they were great about it - did wonders for my opinion of human nature!), and secured the aircraft we couldn't see the tops of the telegraph poles.

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It was way worse than the forecast had led me to believe so where did I mis-intepret it? Those TEMPOs and ISOLATEDs just all seemed to come together across the whole south Wales coast and valleys.

Should we have binned the flight on the basis of those? Maybe at least stayed local where we could keep an eye on it?

Looking after the fact on Weather Underground (what a useful site) you can see the point the temp starts to drop to meet the dewpoint but where in the forecasts could I have found temp and dewpoint data forecasts? Where was the clue that t-shirt weather was going to have us shivering on the ground 25 minutes later?

Was there something in the behaviour of the fronts that could have been a clue? Something in the cloud there was in that blue sky that indicated it was going to change and quickly?

Right this minute I don't really know how not to get caught again based on the data I had to start with...
User avatar
By Keef
#1180228
Glad it worked out! Precautionary is so much better than emergency!

Those forecasts are the "we really don't know what to expect" type. There's something grotty coming, but they aren't sure when it will arrive. Usually, the forecast tends to be pessimistic: on this occasion, the grot didn't hang about and arrived a bit ahead of schedule. It can happen! I don't think there's a lot you could have done differently (but Simon may have a view).

I've set off in CAVOK on a one hour flight, with forecast of CAVOK all the way - and ended up in IMC. I've left France in glorious sunshine, and ended up doing an ILS to minima in Southend 40 minutes later. It doesn't happen often, but it does happen. While I could switch to IFR and use radar and ILS, I wasn't too bothered. In the Jodel, with no instruments (and not much else) I'm more wary. BKN006 makes me think very hard, even if it is forecasted for an hour or two after I expect to have arrived.
#1180230
This is really GOOD NEWS - you might not think so, but you should be really proud of doing a precautionary landing - you NEEDED to do this, and you DID - others would have ended up doing something stupid. People need to read this thread and learn what to do!
There was a year about 10 years approx ago, one month a Cessna took off from Compton Abbas, got caught out and trapped in the hills by 'weather', told D&D and landed safely in a field to 'wait' - now it could have been that the field was smoother than either Compton Abbas or Popham - so why not??? Same year, another Cessna crashed north of Popham in bad weather because the pilot was determined to carry on and not look for a field to put down in.
By johnm
#1180378
Brilliant Leia well done! What a good analysis too. The clue I would have latched onto was the deteriorating vis in the later forecast. That suggests (to me at least Simon might tell me I'm wrong) :x increasing humidity or lowering temperatures towards a steady dew point and that's why you began to find the mist sort of forming around you.

Had the opposite at Alderney yesterday with slowly improving visibility from dense fog as the temperature rose to the point where an IFR departure was doable.
#1180381
METAR I looked at before leaving for the strip was
EGFF 291050Z 25012KT CAVOK 16/13 Q1025

The one I didn't, immediately before departure outbound was
EGFF 291550Z 29016KT 9999 FEW015 SCT024 18/14 Q1026

The one I didn't immediately before departure back was
EGFF 291650Z 28014KT 9999 SCT008 BKN011 17/14 Q1026

So the pattern with hindsight is sort of there - cloudbase was starting to lower but the dewpoint and temp didn't really start to converge by the looks of it until we were up. It's substantially worse by very next one which is when we were in it.

EGFF 291720Z 29014KT 9999 BKN007 16/14 Q1026 (And if that was really 10K vis I'll eat not only my own, rather busy, hat but anyone else's on the menu!)

After that point it goes bang bang bang until it hits saturation later in the evening - happily after we'd found ourselves a Chinese all you can eat buffet two fields over...

METAR EGFF 291750Z 29013KT 9999 FEW004 BKN005 16/14 Q1025
METAR EGFF 291820Z 28015KT 6000 BKN004 15/14 Q102
METAR EGFF 291850Z 28012KT 5000 BR SCT003 BKN004 15/14 Q1025
METAR EGFF 291920Z 30010KT 5000 BR SCT002 BKN003 14/14 Q1026

Before investigating this I hadn't thought of using previous METARs as a sort of doublecheck on the forecast behaviour. Will in future!
#1180383
Worth noting since you do find yourself worrying about the least important things the most at such times - the farmer and family were incredibly friendly and helpful. It was a bit of an embarassing way to start a conversation with utter strangers - "I'm really sorry but we've just had to land in your field....) but they were great abut it. There was no manic sterotyped Gerrof Moy Land going on at all ;) Similar reaction from those on the farm where the other unfortunate weather out from the strip landed too by all accounts.

Also bigger in our heads than in reality was the getting out again, we'd paced the field and picked abort points and gazed at the grass which had seemed to have grown overnight and planned a taxi run first and contemplated the fact we only had a finger in the air for wind assessment, resisted the urge to assume it had to be parallel to the field orientation... but it was utterly uneventful departure in the end.
#1180411
If we had looked again, we'd have seen this:
EGFF 291659Z 2918/3018 28015KT 9999 SCT008 BKN012
TEMPO 2918/2921 6000 BKN006
PROB40 TEMPO 2918/3006 4000 BR BKN004
PROB30 TEMPO 2921/3006 0400 FG BKN001


With 20/20 hindsight this is the key data. It shows a likelihood of deteriorating vis and cloud base as the evening wears on. The Metars confirm the pattern
as you noted, but indicates that forecast times were a little later than actually occured. I think there may be some discussion about the interpretation of that forecast because the restricted language makes it hard to communicate somethings. I would interpret:

PROB40 TEMPO 2918/3006 4000 BR BKN004
PROB30 TEMPO 2921/3006 0400 FG BKN001

"It'll almost certainly be misty and cloud base 400ft from about 6 o'clock, but it might be really foggy and cloud base 100ft" Edited to add time.
User avatar
By leiafee
#1180459
Charles Hunt wrote:I suppose 3 or 4 degree split I'd be aware of but, but not an obvious 'No Go' issue.

One theoretical question, if I may. "What would you have done had you been in TOMS?"


That's an excellent question which I've thought about myself. I suspect my decision making is in something of a state of flux at present...

Differences in scenario...I'd have been heading back to Swansea not Old Park which would have made it twenty miles rather than ten at the point it got nasty. I'd have been going some 25 knots faster. I'd also have been talking to and transponding with Cardiff.

I THINK (although it's impossible to say for certain) I think I'd have made the decision around about Caerphilly or shortly afterwards when we first descended below 1000' to divert. I'd have talked to Cardiff and if they were in it, which they would have been, I'd have tried for Gloucester.

If I was in it even after that and had ended up in the same height and visibilty conditions I hope I'd have landed but it would unquestionably have been a harder decision - I'm fairly confident I could have got the Tomahawk into the field we used but I'd have known that getting out would have been a potential problem and that might have had a bearing even though textbookwise it shouldn't - I'm human and as irrational as the rest of us!

So the microlight 'thing' both encouraged us onwards when we could/shouldhave diverted (low and slow is normal even on nice days...) and made the land out decision easier.

Interesting swings and roundabout there! Timothy talks about 'risk compensation' sometimes, wonder if this is similar...
By NomadAviation
#1180702
Good decision. On Sunday I was surprised to hear at least 3 aircraft talking to London
Info giving details of their VFR routing to Le Touquet for them to be told "it's overcast at 300ft and IFR only....?." Did they even check the weather? The controller must assume we are amateurs! Never assume, check.