Monday 20 May 2013 22:32 UTC
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I took a couple of friends up the other day.
Weather was scattered at 2,200, heavy showers, warnings of the odd thunderstorm. Flew out towards the oncoming weather, giving me the option to turn around if it got very nasty.
Going out we dodged a couple of showers and got sprinkled on by one that was a bit too big to steer around - though we avoided the worst of it. My front seat pax got quite nervous about what rain on the windshield did to the visibility.
When we got to where we were going it was CAVOK, and I elected to stay and circle for a bit to give the weather we'd just come through a chance to get away from us - I didn't want to 'chase' it home and go through it again five minutes later. This didn't go down well with the front seat pax, who didn't like decisions being taken on the hop and implored me to 'stick to my plan'. I placated him/her and continued to circle.
Once I thought I'd given the heavy shower time to build up a lead on us, I turned for home. With about 20 miles to run we caught it up, and by this time it was definitely too wide to go around (in the context of the channel of airspace we were flying in) and it was a big, dark nasty cloud with the base at about 2,000ft, shedding rain like you wouldn't believe. It wasn't building or towering, and it was fairly flat and wide so I think it was cumulo-stratus.... but given it was raining I guess that makes it.... a CB
I decided to go under it, and picked the least angry-looking part - electing to go through at a decent airspeed and get out the other side quickly, because our view approaching it gave the impression that it wouldn't be very 'deep'. Fortunately I was right on this part (about the only thing I was right on) - we were through it in about 60-70 seconds.
But in those 60-70 seconds I've never been more apprehensive in an aircraft. It took just about all my strength forward on the control column to resist the updraft, and even then I could only just keep it below the base of the cloud. The ASI was well into the yellow arc and we were bouncing around like a bead of sweat in an PE teacher's buttock cleavage.
As we came out the other side and things settled down, I checked the altimeter - down to 1,500 feet - and then looked left - we were passing within half a mile of a well-known 1,300 ft obstruction without me even thinking about it.
The fact that it was raining from this particular cloud is nothing to do with the type of cloud, any low altitude cloud can produce rain.
HOWEVER, the other clues all point to this having been a CB, which are at their most dangerous well before they form the "classic" anvil top.
You were actually very lucky that you experienced such an updraft.
You could equally have experienced either a downdraft so strong that it simply pushed you into the ground or you could have had the fuselage in an updraft and the wingtips in downdraft (or vice versa) and I don't need to explain what the result of that can be!
Put this one down to a goodly amount of luck, I am pleased for you that you all came out the other side and landed.
There are two ways to argue with a woman.
Neither of them work!
I know there are a 50+ things to do before getting airborne, but on any day where there are chances of heavy showers, a quick look at rainfall radar is always the order of the day to see how far away and how extensive they are - sometimes it has meant I was happy to go flying in large gaps between bands of showers, other days it has stopped me when the forecast and 'looking out the window' would have got me airborne.
Today's a classic on the South Coast if you look at rainfall radar (free) on the metoffice website or elsewhere - especially run as a movie to see which way they are moving (not sure if you can do that on the free version). Even more so if a solid front is approaching 'somewhere' - you can see where it was in the past hour and with the movie see how fast it is travelling.
We used to really envy the US on trips to Florida in the 1990s due to the weather radar piped into FBOs, now we have it, there are still schools that never both to introduce students to it. Shocking how many pilots are surprised when I check it before a flight, never having done so themselves.
I completely agree with Irv about the usefulness of a rain radar. As a student I never knew about it, but nowdays I have it as an application on my Adroid phone. I have tried a few, but have found "Rainy Days" to be one of the best. It plays a 15-minute per frame movie overlaid on google earth with your current position highlighted as a dot. It is very useful when you are away from your your normal pre-flying computer. I have found that a 1 to 1.5 hours forecast is achiveable with accuracy and exactly what you need before you start up the airplane.
I'm interested in the views of the far more knowledgable than me expressed here. I'm still far too low hours to have much experience, though I have had my share of flying in 'British' weather...
For instance I have heard that 'wings in an updraft, body in a downdraft' warning before. Has that really been encountered by anyone (who has lived to tell the tale of course?)
I have also experienced pronounced updraft going through a patch of rain - funny how the temptation is to put on a bit of speed to get through it quickly when the opposite is probably true for ease of handling - has anyone experienced severe downdraft sufficient to chuck one close to the ground as well?
Rain on a windshield is a bit disconcerting at first but as long as it doesn't last too long and one is within one's licence/rating limits, then it's not terrible is it?
Don't take this as a poke at anything that has been said here - I always read this part of the site first as it's a great way of warning one on potential pitfalls - but I'd be interested to hear further views on what is 'dangerous' and what is deemed as 'good to experience' once in a while. Britain and its weather being what it is.
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Like you, George, I've heard "wings in updraught, body in downdraught" but it must be a very brief and transient thing in a 20-feet-wide aircraft doing 90+ knots (which is 152 feet per second). It's all past in about a tenth of a second, which isn't enough for anything less than a violent CB to do a lot of damage.
The nearest you will come is flying through a col or past one, when the "bump" can be impressive. I've banged my head on the roof a couple of times (notably in California and Arizona, but also at Shap).
Yes, I've been in nasty updraughts and downdraughts, although I treat CBs with great respect. Slow to the recommended speed, keep going straight, and wait to come out the other side.
The more important rules are the survival ones: never cross a ridge at right angles - it takes noticeably longer to turn away if you run into sink that threatens to smack you into the ground. 45 degrees is my rule - others will no doubt have other opinions.
Moderatio in omnibus
they may have other opinions, but this is what I was just recently taught when doing Met theory and discussing flying in the Alps. And makes sense. You need less space to get out of a situation at a 45° angle.
PPL-Student: 52:00 Total, of that 1:30 solo, Cessna 150 41:01, Cessna 172 10:59. All Exams passed.
No criticism from me. We all have done stupid things out of inexperience; the important thing is to learn from them.
So a few things that you might learn from this if you haven't already.
1. Going fast to get through rough weather quickly isn't a good idea at all. For one it can exaggerate the bumps. Bust most of all your aircraft is designed to handle turbulence, much more than you will be comfortable with, without damage. But by the time you get into the yellow arc, you are now in an area where the turbulence can damage your aircraft. Better to go slowly through and take longer to get through, knowing that your aircraft won't be damaged, then to go through quickly and hope for the best.
2. Best not to go through narrow passages of airspace, leaving yourself no room to manoeuvre, on days where there are heavy showers around, unless you are extremely confident of getting transits of those airspaces if needed.
3. If you need a transit of some airspace to get around some weather, ask for it. Make it clear that you are looking for the transit because there is some weather that you can't go through (rather than simply looking for it for a short cut). You are likely to get the transit or some version of the one requested.
4. Clouds move much slower than aircraft. No matter how long you leave it, if you were going in the same direction as the cloud then you were virtually guaranteed to meet it again. At absolute minimum you were likely to be travelling at twice it's speed, but most likely a lot more. Your chances of letting it get and stay ahead of you were remote, and you should have been looking for a way around it.
I'm also surprised about your comments about it taking all your strength to keep the aircraft level, and then finding yourself low. To me this suggests panic rather then thought. In fairness I think you've pretty much recognised that yourself. You will never pilot an aircraft well if you are using all your strength. That is the stuff reserved for movies. If you are in a major up draft and need to keep a strong pressure forward on the yoke, then trim it off! Think your way through the problem. Trim is for relieving forces. I suspect this is why you found yourself low....you came out the far side still holding major nose down force, with all your mental effort being to hold it down. Trim would have allowed you to use less brawn and more brain.
Congratulations on recognising your failings and owning up to them. It will help you to be a better pilot. Too many people refuse to recognise error that they have made, and as a result don't learn from them. You will learn from this, and continue improving.
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