20015G25KT - what do you do?
 

Whenever I see GxxKT in a TAF, I don't fly, irrespective of the other conditions. Recently there's been quite a bit of GxxKT in the TAFs (with some clear blue skies) but I've noticed that people are still flying.

Am I being unnecessarily strict on this? Does the GxxKT indication suggest that the gusts are 'continuous', or sufficiently infrequent that you could make a safe landing after a few Go-Rounds or is it entirely up to your own judgement of the other prevailing conditions?

Or what?

Provided I could use Runway 20, I wouldn't be particularly concerned!

A gusting TAF means that at some point in any ten minute period, the wind speed might exceed the mean by 10kt or more.
As long as the crosswind factor isn't beyond my capabilities (which I consider to be somewhat less than the published figure), shouldn't be too much of a hardship. Depending on the aircraft type, higher approach speed or lesser flap settings can all be used to make things more comfortable.

The simple answer is that if you're not comfortable with the weather, don't fly!

However, 15G25kt, as long as it's reasonably in line with the runway, shouldn't present any problem for most pilots in most common training-type aircraft.

Given that you shouldn't fly if you're not comfortable with the weathe, the best solution has to be to get yourself comfortable with this kind of weather. On a day where this kind of weather is forecast, try to find an instructor who has an hour of free time to do some circuits with you. It shouldn't take more than one or two sessions like this before you become confident enough to go flying on days like these yourself.

Don't confuse gusty winds with gusty crosswinds, though - a completely different ball-game, and not to be tried unless you are very current in the aeroplane, and very confident about your cross-wind ability.

FFF
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15G25Kt with some G30Kt at Leics today and plenty of aircraft flying. We had both of our Cessnas out and the school was training.

Dealing with any conditions is down to currency and experiance. If you don't feel comfortable with the conditions then you are making a good call by not going flying.

As FFF says if you want to stretch the envelope and are not confident enough to do it on your own then seek instruction. You will soon realise that with currency gusting wind is nothing to worry about.

And as you mentioned yourself, you can always go-around!

I got caught out with the gusting crosswinds at my destination today. The TAF was right and the wind did build up towards midday and was gusting to 30 kts. However when I left the home strip it was straight down the slot and no problem. I must confess that my departure was angled to take into account the width of the destination runway and that got me about 10 degrees nearer into the wind. In the event it was no problem but it was a choppy ride home.

I gave up on the plan to head to North Weald and opted for WW instead.

It took me 11 minutes to get there and 35 to get home!

I decided to try something out over Newbury and that was to see how fast I could fly backwards. 4000 feet on the QNH, powered right back, nose up and I managed 6 knots in reverse with 38 knots indicated! What a strange feeling. It was interesting that I had to steer 310 degrees to be right into wind at that height and and ground level the wind was right down the strip (260 degrees).

It didn't seem particularly gusty today and as long as the wind is straight down the runway, winds like today's can give some rewarding flying.

That sounds about right Monocock. Form 214 had the 2000 foot wind as 280/40kts so 38kts indicated plus 6kts in reverse is about right. I agree with your comment on the direction though as it was right on my nose at 320 degrees but right down the slot at ground level at 260 dgrees. At least i flew.

Sure was gusty at North Weald today. We were using R/W 20, but the wind was 250 at 17 kt this morning, getting up to 280 and 20G32 during the afternoon. We still had about 100 movements though, and only one I think who gave up the approach and went home. Much more sensible than trying to land and failing... jayemm, why don't you get an instructor to do some circuits with you on the next gusty day.

jayemm,

My personal take on it is that handling a 10kt change in headwind can be a tricky business. Having a 25kt headwind and then having a 15kts headwind is effectively windshere. You only have to read the AAIB reports to see plenty of accouts of wind drops and leaving the runway at an angle with the closing sentence "The pilot believes the cause was windshere". May not be so much of an issue for a C152, but I probably would not risk our AA5A in those conditions.

Another thing to remember is that the wind may well be down the runway, but may not stay like that. A quick look at the synoptics should give you an indication what kind of wind direction change and speed to expect later in the day.

FWIW, I believe that some operators stipulate that the commander add half the gust speed to the wind speed and determine the cross wind component from that.

Something that GASCO and the CAA keep reinforcing and something that I personally have so far taken heed of is, that just becasue you didn't have a problem last time...

Just my personal view that may change with experience.

It certainly was gusty today - we had an interesting "arrival" at Welshpool where the wind was ~25kts at about 45 degrees off the RWY heading (RWY 22) but the tricky part was that it was turbulent with it at low-level, lots of shear and veer. My buddy Adrian had to go around on the first attempt - discretion always being the better part of valour! We had planned Shobdon for an alternate as their RWY 27 would have been much more into wind, but didn't prove necessary in the end.

I flew us back to Wycombe and it was pretty choppy climbing out of Welshpool, just as the showers were arriving there, and at Wycombe it was varying 15~20kt about 30 degrees off the RWY heading (RWY 24), but the terrain is less lumpy and bumpy there so I didn't find it as tricky.

jayemm, I think you should take the GUST indications in the TAFs as a warning and take care that your destination is reasonably into wind and if not plan an alternate which is! And, as others have said, definitely build up some experience with cross-winds in a safe way (with an instructor or at least a more experienced person who is competent in the conditions). Best bet is to take up an instructor on a ~15~20kt day and go fly the crosswind runway at your homebase or somewhere suitable nearby. Practice makes perfect!

Another issue in relation to crosswinds is that I think everyone has a technique that works best for them: for myself for example I am most comfortable wing-down with the crab off from about 1 mile / 300 feet as I find that I can stabilise the approach better rather and prefer this to kicking the crab off just before the flare. Many other people prefer to crab all the way down then kick the crab off. The point is without practising both techniques, with competent instruction, it's hard to learn which works best for you.

Besides all this: wasn't it a superd day today? We could see for MILES!!!

Andy :ok:

Very important points to remember are that;

a) The TAF forecast average windspeed is just that - an average. The actual wind at any moment may be more or less than that speed at any time.

b) Gusts are only reported and are only forecast if they reach 10Kt above the average.

c) The diection is also averaged and changes in direction will only be reported if they are 30 degrees from the average.

Thus a wind forecast of 23015 can mean;

Wind direction varies from 200 to 260 and speed varies from 4 to 24 Knots.

If the max wind reaches 25 then the report will say 23015G25

But is that 1 knot change in windspeed really so different from what went before?

Also worth remembering is that in the northern hemisphere when the wind gusts the direction veers. Thus if landing with a crosswind from the right, if the wind gusts the direction will move further away from the runway making the effect of the gust even more apparent!

regards,

DFC

I think that is a very good point. It might be worth reading TonyR's post on flying by numbers in the Flyer forum. I think it is exactly this kind of thing, of which I am as guilty as the next pilot, that he is criticising.

I think you're mixing up METARs and TAFs here, DFC.

In a METAR, variations of more than 60 degrees (typically 30 degrees each side of the mean) direction are reported.

In a TAF, there is no forecast of directional variation. VRB is allowed for means above 3 kt only if it is impossible to forecast a single direction, which is usually reserved for temporary conditions in convective activity.

So a forecast of 23015KT gives not even that weak guarantee over direction. The 230 is a mean, but the wind may be traversing 140 to 320 or worse.

All the more reason to fly the weather you find, not the weather that is forecast.

An interesting mixture of responses here, and mostly helpful, thanks.

Clearly a lot of us do fly when gusting is in the TAF or is actual, which in itself has persuaded me to adjust my "No Fly" rule (with all the usual caveats).

I'm not so concerned about cross-wind experience; you can't really fly in the UK without sorting that one. It's the windsheer effect that you can get which seems a bit of a lottery, the risk being that you cannot predict whether you'll be in veer, sheer up or sheer down. Can an Instructor really help on that one?

matspart3:

Is that an official definition? I couldn't find it.

They're both similar problems... you need to be ready to react quickly with aileron and rudder (crosswind) as well as throttle (for vertical shear) and when conditions are tricky, make the go-around the default action in your mind and only land if on short-short final you are really OK about everything... pointing straight ahead, on the centreline with no lateral drift, flaring nicely etc. and if not then go-around. This decision is always easier too if you have a diversion to an into-wind runway already planned ;)

Andy

20015G25KT - what do you do?

Carry on and feel glad it's not very windy today! :p

Once arrived at a jet training station with my little Bulldog. Got a very angry duty instructor asking me what the hell I thought I was doing as jet flying had apparently been stopped for the day due to the 30 kt crosswind. I pointed out the fact that the Bulldog's crosswind limit was 35 kts and carried on booking out... :cool:

Once had a casevac in an Asian typhoon (major heart attack) where we had 75 kts IAS in the hover over the landing site, which was a basketball pitch surrounded by lamposts. The wind dropped to much less as we landed, which made for some interesting control inputs....

Another time, recovering 3 military personnel from a tiny island, the aircraft wouldn't land due to updraughting - we were flying in autorotation at 10 feet. Once the wheels touched, three very grateful soldiers leapt onthe aircraft like ferrets up a drainpipe. 90-100 kt winds took us home very rapidly!

If in doubt, just land across the runway! ;)

Jayemm,
You may want to consider the application of meteorolgical terms from a typical commercial operations manual.

'Gust value in TAF- Disregard'.

Also, the wind correction to approach speeds should be considered.

'Add 1/3 of the headwind component or the gust value in full though max. 15 knots total'.

Thus, anything requiring more than 15 kt of wind correction will also require more than normal workload.

TAFs are only forecasts and I reckon you're doing yourself out of some really nice days; sometimes you don't even have to go much over 1000' to get out of the turbulence.

But do stay on the safe side.

The official definition, in WMO Doc 306 Manual on Codes, is not very enlightening. It merely calls for a Gxx value to be included when the maximum value of the wind speed is forecast to exceed the mean by 10 knots or more.

If the max wind component from a gust exceeds the aircrafts cross-winds limit. i.e. RW18 09015G25 and crosswind limit=17kts then you may find you insurance will not cover you.

At my school if the tower reports wind such as this on final then we must go around and try again until the wind drops or we divert. Sure, we could land in those conditions, but if the unlikely happened then the school/instructor is left to pay for the damage. As the RT at major fields is recorded the nice insurance men will be checking that before even looking at the aircraft.