Wind Speed and New PPl.

[28thJuly2001]

What would you consider to be a high wind speed?
I fly a Tomahawk and the other day the wind was 18G28 40 degrees off runway heading when I landed. I didnt have any problems landing and would like opinions on whether this wind speed is high or am I just a big girl.
The wind was steady at 16kts when I took off and must admit my **** twitched a bit when I checked the ATIS prior to landing.
Walt,,

[GoneWest]

40 degrees off - as you probably know - will give you a cross wind component of two thirds of the full wind strength...so 18G40 will gave you 12G26.

One of them is approaching X wind limit of the PA38 (for an experienced pilot) and the other is way above .... so no point in paying for insurance.

Whilst on the subject, I remember a mega experienced instructor/examiner saying "don't taxi in a surface wind of more than 50% of the aircraft stalling speed".

[Final 3 Greens]

28th July

Firstly, there is no "crosswind limit" for a PA38. It has been demonstrated by the manufacturer to handle a crosswind component. I don't know what the number is for a PA38, but it is 17kts for a PA28.

Landing it above this demonstrated component doesn't mean you will crash - but then again as you didn't, you know this! ;)

These sort of things do happen when you are a new ppl and exploring the limits of your ability - one of the guys in our group managed to land in a 40Kt wind the other week (straight down the runway) and whilst he was okay, I don't think he will do it again .... therefore he will be a little more cautious when interpreting the forecast in future.

If this sort of situation ever arisies again, you might wish to consider a couple of options:

1 - is there a nearby airfield with a runway more into the prevailing wind

2 - is there an airfield where the wind is less (it can happen)

Either of these give you divert options.

My rule of thumb on gusting crosswinds is to take the mean gust component (gust minus wind speed) divide by two and then add that to the base wind speed, so in this instance 26-12 = 14 divide by 2 = 7.

12 + 7 = 19kts - probably a little over the demonstrated figure for a PA38, but not that much.

However, if you are unlucky enough to get the full blast of the highest gust at a critical point, you will have to work harder to keep contorl.

All in all, I think that you have had a good learning experience and also have shown that your PPL training and ability were capable of handling this situation.

Its always worth looking very carefully at the forecast winds in your locale (avbrief is very good for this www.avbrief.com), but also try and understand what is happening with the weather around your airfield - is there a change of wind coming from east, west , north or south - you can see the forecast on Metforms 214/5 (again from Avbrief) and also the METARS where you can see the actuals developing.

There's a lot to learn with a new ppl, but you'll catch on quickly.

[GoneWest]

Final - you are correct...there is no "limit" - only that demonstrated by a company employed test pilot.

It's 17 for the PA38, as well.

Still doubt that the insurance company would pay out if you rip the wheels off, and stop the prop. on the ground, after bursting a tyre because you broke the seal due to side loads on the undercarriage by landing in winds greater than Max Demonstrated (is there a V reference for this speed??).

I used to fly a PA31 (Piper Chieftain), professionally. The aircraft had a max demonstrated of 20kts - the company had a max surface wind for taxi of 40 kts. Wind any stronger than 40 - we would cancel the charter. Seemed to make sense.

[Final 3 Greens]

Gone West

We would probably both agree that pilot capability is often the real x-wind limit.

For example a Bulldog (2 seat military trainer) that I have flown has a demonstrated crosswind capability of 35Kts - but I wouldn't try it!

The number you quoted in your first post of half the stalling speed is a number I have heard used before to decide whether to fly at all.

If you take my gust rule of thumb and the wind speed is say 25kts, then I would think very hard before flying a light single due to the potential for shear and speed loss.

I've only flown a PA31 once, so can't comment on that type, but what you say makes sense - if nothing else, you'd scare the pax and that may not hlep future business!

[BEagle]

Final 3 Greens - You said:

“My rule of thumb on gusting crosswinds is to take the mean gust component (gust minus wind speed) divide by two and then add that to the base wind speed, so in this instance 26-12 = 14 divide by 2 = 7. 12 + 7 = 19kts”

It’s much easier just to use the average windspeed! If the wind is A, gusting B, then the average wind speed is (A+B)/2. You are calculating B-A, halving it and adding it to A. That’s B/2 - A/2 + A....which is the same as B/2 + A/2....which is the same as (A+B)/2 !! As you will note from your example, (26+12)/2 = 38/2 = 19 !!

I’m interested in the ‘stalling speed divided by 2’ idea - at the moment for the PA28 we use:

Non-PPL holders: 25 kt surface wind, 10 kt crosswind component.

PPL holders with less than 100 hr P1: 25 kt surface wind, 12 kt crosswind component.

Pilots with at least 100 hr P1: 25 kt surface wind, 17 kt crosswind component.

Instructors: 35 kt surface wind, 17 kt crosswind component.

I went flying the other day in a PA28 with a surface wind of 21 kts down the runway, gusting 33 - and it was very unpleasant!

[28thJuly2001]

Thanks for your comments.
I will put this flight into the "luck" v "experience" file.
Walt,,

[Final 3 Greens]

BEagle

I just like doing complicated sums to impress the proletariat!

BTW, don't you think that the intensity of the gusts is a big factor?

21G33 would make me think very seriously about flying in a PA28 (it is also bang on top end of my rule of thumb, since the PA28-181 has a clean stall speed of 54 kias), as there is the potential for enough airspeed loss on final to make life difficult for my skill/experience level - it's doubtful that I would go. I certainly wouldn't even consider flying in our little Pup 100 in such gusty conditions.

However, I acknowledge that you are a much more experienced pilot than me, so your "unpleasant" experience was no doubt well within your envelope.

[BEagle]

Actually it had been 18G28 - and it was supposed to be decreasing further. When we took off (in order to standardise a new FI(R)) it was 21 - when we came back it was G33! So we taxiied very slowly and carefully back to the hangar and put the ac away for the rest of the day! I wouldn't choose to go flying in a Warrior with 33 kt gusts again!

Nobody went flying at all that day at Kidlington - very sensible decision.....

The next day I did myME MPA IR and afterwards chatting to the IRE we discussed strong wind hazards. I've always thought that wind can be a much bigger hazard than low cloud/poor vis/ carb icing - because you can't see it!

Full marks to Walt 28thJuly2001 for 'learning from that'!

[Genghis the Engineer]

Read into this whatever you will, but in the last fortnight I've seen two landing accidents entirely as a result of wind.

The first was a Europa at Compton Abbas RWY 26 in S-SW, 18G28, which couldnt hold the runway, ran off the side and broke off his tip-draggers. I'd landed 10 minutes before in a type I have 150hrs on (and has a 12 kn X-wind limit) and had struggled quite badly to hold the centreline.

The second was a Blade at Popham RWY 03 in about N, 15G25 (my estimate, I wasn't flying so hadn't checked the met all that carefully), which was tipped over at the end of it's landing run.

In both cases, the pilots were almost certainly on the edge of their "demonstrated crosswind or total-wind limits" ( I know that it's about 12 kn for the blade, but haven't flown a Europa), and plenty of similar types had just landed before, and continued to land after. I've no reason to believe that either pilot was just qualified or inexperienced.

I think my only moral here is that the stronger wind gets, the more the odds stack against you. Experience and an aeroplane that can take it help, but the most experienced pilot has some risk of not getting it right in the wrong wind conditions.

Sadly I speak from personal experience. I have broken an aeroplane due, partly, to wind that shifted from crosswind to tailwind as I rounded out. (Not, I hasten to add, that other misjudgements on my part didn't contribute too).

G

[HelenD]

I was up the other week doing X wind landings in a 14kt X wind, it was hard work and wasnt fun. Whether the wind contributed to me stuffing up a go arround or not I cant tell. Thankfully I was with an instructor. I do know that I wont willingly go up in such winds again pre or post gaining my PPL.

[Final 3 Greens]

Genghis

There for the grace of God go I.

I had a stiff crosswind back to a tailwind on round at at Fenland a couple of years ago.

Just got away with it - thank goodness I was flying a forgiving type that sorted itself out.

[englishal]

Maybe we should all write down our max 'demonstrated' cross winds and send them to Piper. Then they can issue an amendment to the POH with an increased demonstrated cross-wind figure :p

[GoneWest]

BEagle - is that list of school limits for DUAL or SOLO...or BOTH?

I notice that HelenD says she was doing dual training at 14kts - and her last line suggests she is pre PPL.

What does your school order book say??

[Final 3 Greens]

Englishal

You going to indemnify them in case those limits are judged to be too high by a court ;)

Perhaps this explains why a Pup 100 was said by Beagle to be capable of handling 25kts x-wind in the 60s when litigation was unpopular!

[BEagle]

GoneWest - those limits refer to the aircraft captain. There may be occasions when instructors need to fly in strong winds, but not to instruct students. Hence the upper limits of 35 kt or 17 kt cross-wind which are a absolute no-bust limits.