Cross Wind

[Mothfly]

Had to land a Tiger Moth at Bankstown Airport in a 15kt cross wind last Sunday due there not being a cross wind runway ..... I did request from the tower if I could land on the taxi way in front of the tower but this was refused ....cross wind limit for a Tiger Moth is 10kts

[Scion]

Did you have turbulence from the Toll building on 29 right?

[uncle8]

cross wind limit for a Tiger Moth is 10kts

Not for pilot of your calibre. Good practise for you.

[4forward8back]

Crosswind limit is actually 10MPH.

At 15 kts, you did EXCEPTIONALLY well not to drag a wingtip.

I doubt you'll ever get clearance to land anywhere other than a runway for normal ops.

Had to land a Tiger Moth at Bankstown Diversion is always an option.

[4forward8back]

Essential reading for all Tiger operators:

Downloads | Tiger Moth Club of New Zealand Inc (http://www.tigermothclub.co.nz/downloads/)

[KoolKaptain]

So why didn't you proceed to your alternate?? Operating an aircraft outside the parameters it's certified to operate in must surely call for an ASIR... Unless of course 10 MPH is the "maximum demonstrated" crosswind, in which case it wouldn't be considered limiting.

[Capt Fathom]

You should have diverted to Sydney International. :E

[josephfeatherweight]

Most of the pundits have referenced this above, and, of course, we don't know the "full" story, BUT, the word of concern from the original post is "Had" as in "Had to land..." Maybe you did not have sufficient fuel to divert, but if this had not ended as magnificently as it seems to have, you'd be up the creek wrt insurance if you blatantly ignored an aircraft limit. Can you give us more background? Genuinely interested.

[ACMS]

Well as a last resort

"Mayday mayday mayday......we ARE landing on that taxiway so clear it"

[PA39]

The maximum x/w component for a particular aircraft type is demonstrated for certification purposes only. this does not mean that you or the aircraft can't be capable of landing in excess of this figure. You must practise this until you are very comfortable with your skill level.

[Frank Arouet]

Your skill level ends when you run out of rudder control.

[Dora-9]

Your skill level ends when you run out of rudder control. Well said that man!

[4Greens]

Tiger Moths were expected to land on grass and hence there would be no problem with cross winds.

[desmotronic]

land across the runway almost doable?

[Frank Arouet]

Why didn't you just land on 18/36?


Oh, sorry.

[HotPete]

We let them close 18/36 with hardly a whimper

[josephfeatherweight]

The maximum x/w component for a particular aircraft type is demonstrated for certification purposes only. this does not mean that you or the aircraft can't be capable of landing in excess of this figure.

And, the point is, Mothfly thought it was a limit! Maybe it is on the Tiger Moth?
I'm not wanting to castigate our friend Mothfly, there's always more to a story, again, I'm genuinely interested to know more. I'd love to fly one, one day!

[The Green Goblin]

Last time I checked boys 10mph equals 16kph.

15kts equals almost 28kph.

I would have declared a panpan and advised I was landing on the taxi way.

[Centaurus]

Tiger Moths were expected to land on grass and hence there would be no problem with cross winds.

Which is probably why there is no mention of crosswind limits in RAAF Publication No. 416 February 1944 Pilot's Notes for Tiger Moth Aircraft. By command of the Air Board no less and signed by the Secretary at Air Force Head Quarters, Melbourne, S.C.1. To be used in Conjunction with A.P.1732A :ok:

[mattyj]

..yeah true..and the RAAF hardly crashed any tiger moths

[kaz3g]

I flew into the Alice last year in less than pleasant conditions...very strong nor-easterly but swinging through more than 90 deg in gusts, a lot of thermal activity as well. The ATIS gave RWY 12 as active.

It was a rough ride inbound from Deep Well and the updated weather from the nice lady in the tower did nothing to build confidence. I asked if the grass was available and explained about Austers in crosswinds.

She gave me a "standby" and then came back with "not available".

I said: "This could be ugly!"

She instructed me to orbit while she got rid of an RPT. I looked longingly at the old NE-SW runway turned taxiway and headed for the big black as directed.

There is a God...on short final with what felt like 60 deg laid off for the wind, it suddenly veered and became a wonderful headwind of about 20 knots.

I plonked her down as quick as I possibly could right beside this lovely, wide, mown grass verge, and managed to turn in the shelter of the terminal to taxi to the parking area...Auster brakes were an after-thought.

I got an invitation to go up to the control deck and asked what was wrong with the grass.

She said she thought it might be too rough!


Kaz

[rjtjrt]

I got an invitation to go up to the control deck and asked what was wrong with the grass.

She said she thought it might be too rough!
I wonder in this wonderful age of litigation and risk aversion, if this is the tower staff not wishing to accept a non standard landing surface request in case they are liable for any problem.
If this is the case, they are probably hoping the pilot in command will issue a pan or whatever, and then they can be more helpful.

[uncle8]

I agree with rjtjrt.

As a clue, there is CAAP 92-1 "GUIDELINES FOR AEROPLANE LANDING AREAS" which describes the runway strip - “runway strip” means a portion of
ground between the runway and fly-over
area which is in a condition that ensures
minimal damage to an aeroplane which
may run off a runway during take-off or
landing;

[no_one]

I wonder in this wonderful age of litigation and risk aversion, if this is the tower staff not wishing to accept a non standard landing surface request in case they are liable for any problem.
If this is the case, they are probably hoping the pilot in command will issue a pan or whatever, and then they can be more helpful.


When a hellicopter asks for a takeoff clearence from somewhere that isnt the active runway (ie a movement area) in the US, ATC will append "at own risk" to the clearance. Why couldn't something similar be done here for non standard runway opps?

[currawong]

Pilot in command has the final say.

But must be able to justify oneself.

ATC instructions/clearances are complied with as a matter of course, not because they are "orders".

This case is no different to an ATC request for a climb or descent that is outside the performance of said aircraft.

Having lit the fuse I will now stand well back.:E

[ChrisJ800]

Ive landed a Moth at Camden and used 10/28 which is a grass strip. 06/24 is the main GA tarmac strip.

[MakeItHappenCaptain]

So why didn't you proceed to your alternate??

Alternates are not always required.

[KoolKaptain]

"Alternates are not always required".

Ummm... Yes you are correct. In this case however, an alternate would have been required (in case you need it spelt out for you, it is due to the winds at the planned arrival port exceeding the crosswind limit for the aircraft. Pretty simple really).

[josephfeatherweight]

KoolKaptain, are you saying that in his case, prior to takeoff, the forecast indicated that the crosswind would exceed the limits of the aircraft? (I don't know what the forecast was.) Maybe chill your smarmy tone?

[poteroo]

Back in the early 80's, I received a visit from a DH-82 owner/pilot who needed some agronomic advice. At the time, I lived on a farm 240 kms NE of Perth - in the sticks so to speak!

He mumbled a bit about the fact we had a 'runway' at the farm, but I didn't give it a thought until he arrived overhead. With a 25kt hot northerly blowing, he had one try at the E-W runway, prudently gave that away, then lined up on the 'finish-out' headland in the young wheat crop and floated down to a perfect 3 pointer - which took all of 50m into wind.

But, we had to then lift the tail up by hand to taxy him back to clear ground as there was no tailwheel - just the original skid. That was pretty much the condition of the entire aircraft - it was right out of a WW2 training station.

The owner/pilot was a real 'original' - wrinkled skin, faded and scratched leather jacket and leather flying helmet. " You need a 100m circle in the middle of this paddock" he said - " then I can handle any wind direction". "Don't think I can sell that idea to cockies" thought I.

"Can't say I was ever taught to fly in crosswinds" he admitted - " it never seemed necessary when every farm had plenty of pasture, but since you young blokes have begun to plant every paddock down to crops it's all getting difficult"

Well, the wind blew, the sand flew, and we had to hide the DH-82 behind a line of mallee for a few hours. Finally, we had a lull, and he was able to make a rather erratic takeoff on our strip. Last I ever saw of the old gent, or of his DH-82, but he surely didn't take any risks in crosswinds.

happy days,

[Lead Balloon]

Is the number in the Moth POH a structural limitation (i.e. the crosswind at or below which the airframe has been demonstrated as capable of enduring for the life of type if no correction for the crosswind is made during landings) or an aerodynamic limitation (i.e. the crosswind at or above which the airframe has been demonstrated as incapable of compensation on landing, despite control inputs from the pilot)?

[kaz3g]

Is the number in the Moth POH a structural limitation (i.e. the crosswind at or below which the airframe has been demonstrated as capable of enduring for the life of type if no correction for the crosswind is made during landings) or an aerodynamic limitation (i.e. the crosswind at or above which the airframe has been demonstrated as incapable of compensation on landing, despite control inputs from the pilot)?


Did the Tiger have a POH? The Auster didn't and flies with an exemption.

According to AOPA, Air Safety Institute Instructor Reports (http://www.aopa.org/asf/publications/inst_reports2.cfm?article=3651)

"As with most aircraft performance parameters, there is a number to guide us. The manufacturer provides a demonstrated crosswind component in the normal operating section of the pilot's operating handbook (POH). This is not the maximum side wind that the aircraft can theoretically handle. It is the most wind that the test pilots actually experienced while testing the aircraft for certification. The numbers are usually fairly high. For example, the Cessna Turbo 210 was tested to land safely in 21 knots of direct crosswind. For most of us, that will probably suffice on a day-to-day basis, and the majority of CFIs recommend that demonstrated crosswind be considered the aircraft's limit."

Kaz

[kaz3g]

In his book on Johnie Johnson, Dilp Sarkar recounts that Johnie flew the squadron Auster down to Rearsby on a day off in order to participate in a test of the latest Auster IV conducted by the Chief test pilot, Mr Waite.

The both got in and Waite lined it up on the runway. He announced he would demonstrate a short take off and promptly opened the throttle while standing on the brakes until the tail assumed the level for flight. Waite then released the brakes and "we were off in a very short distance indeed."

In the Auster book there is another story about the doings of Mr Waite. Apparently he did a similar demo in an AOP5 in front of the "brass"...except he announced he would take off over the manager's little Standard 10 parked ridiculously close down the runway. He almost cleared it!

But he subsequently gave a very good demo of how to land an Auster on one gear leg only toppling at the end of the landing run.

I gather the tradespeople at Rearsby had panel eating skills as well.

Kaz

[Lead Balloon]

Indeed.

But many people discuss crosswind limitations without realising that there's a Venus/Mars thing going on.

There are two kinds of crosswind limitations.

The first - structural limitation.

Imagine a runway aligned north/south and a crosswind from the east or west. Irrespective of the amount of crosswind, it is possible for a pilot to manoeuvre any aircraft in wings-level flight so that it 'arrives' at the threshold of the north/south runway, pointing directly north or south, at any amount of crosswind.

However, when the aircraft 'arrives' at the threshold of this north/south runway while pointing north or south in wings-level flight, it will be moving east or west at the speed of the crosswind. That will put stress on the airframe.

For example, imagine an aircraft pointing north on descent in wings-level flight, being blown sideways at 20 kts, arriving at the threshold of a north facing runway. The aircraft is moving 'sideways' at 20 knots when it touches down. That has to be 'absorbed' by the airframe, or the airframe breaks.

The second - aerodynamic limitation.

Imagine a runway aligned north/south and a crosswind from the east or west.

The pilot wants to maintain a track that is aligned with the runway centre line, so that on 'arrival' at the threshold the aircraft is not moving east or west, but instead only in the direction of the runway.

In this case, there will be a crosswind above which it is not possible for the pilot to maintain a track that is aligned with the runway centre line, because no amount of control input can compensate for the drift caused by the crosswind.

Of course it's a bit more complicated than this simple distinction, because a lot of other factors come into play once the aircraft is in contact with and rolling along the runway, but an understanding of what the number actually means is important.

[Cloudee]

Don't forget we are talking Tiger Moth, a tail wheel aircraft. If you try to land with any sideways movement on touch down it will try very hard to swap ends. This will happen well before any structural limitation is reached. The only limitation needed when discussing Tiger Moths is the aerodynamic limitation.