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Demonstrated X-wind in the POH - exact meaning?

Most light aircraft have a demonstrated X-wind figure in the POH, which might be considered conservative. I understand it's not a limit.

If you have a landing incident - say a collapsed nosewheel, with a X-wind of 10 kts above the demo-wind, would your insurance cover be invalid?

Swanborough Farm (UK), Shoreham EGKA, Soysambu (Kenya), Kenya

Unless there is an actual published limitation in the POH, you will have not exceeded any limitation exceeding the "demonstrated" crosswind limitation therefore I do not see on what grounds insurance cover can be denied.

Wine, Women, and Airplanes = Happy
Canada

The actual requirement for the certified aircraft reads:

"A 90 degree cross-component of wind velocity, demonstrated to be safe for taxiing, takeoff, and landing must be established and must be not less than 0.2 Vso"

So to be certified, a test pilot has to have demonstrated this, without applying skygod like skills. When Vso has been established during testing, you then have a speed from which to derive the minimum demonstrated crosswind.

The minimum must be demonstrated for certification. There is no requirement to state or limit to a greater value than that. There is zero incentive for the aircraft manufacturer to declare a higher crosswind speed, as that becomes an invitation for a pilot of any skill to attempt more demanding flying. Invitations which lead to failure, lead to lawsuits. The manufacturer gains nothing publishing a higher crosswind speed, those who wish to try it can go ahead, and they know that. If the pilots who do not know are put off attempting it by the flight manual value, perfect!

I would imagine that there would come a crosswind intensity, where after the accident, the insurance company would say "wait a minute, did you really think you could do that?" and it won't be an easy sell. I would be extremely cautious at speeds much greater than the demonstrated speed in the flight manual, but yes, you are permitted, and you have reasonable expectation of insurance.

This fellow attempted takeoff in direct 25 knot crosswind (I was there10 minutes after the crunch). I cannot imagine why, as there was a longer runway right into the wind available! I would expect there was a "discussion" between the insurer and the pilot - I did not hear.

[(http://i381.photobucket.com/albums/oo252/PilotDAR/Aircraft/IMG_1417.jpg)]

Home runway, in central Ontario, Canada

It's quite useful to look at AC 23-8C too.

Page 104

  1. § 23.233 Directional Stability and Control.

a. Explanation.

(1) Crosswind. This regulation establishes the minimum value of crosswind that must be demonstrated. Since the minimum required value may be far less than the actual capability of the airplane, higher values may be tested at the option of the applicant. The highest 90-degree crosswind component tested satisfactorily should be put in the AFM as performance information. If a demonstrated crosswind is found limiting, it has to be introduced in Section 2 of the AFM.

I would deduce that in the absence of a limit in Section 2, the demonstrated crosswind is clearly not limiting.

Many thanks for the info - there's quite a bit to think over. I guess one aspect to consider is the crosswind given by ATIS or Tower is measured (at least at my home airfield) at 30'.

So, additional question, is there a requirement to define at what level the wind is measured? A windsock 'reading' is going to be different from an anemometer (?) up on the tower roof.

Swanborough Farm (UK), Shoreham EGKA, Soysambu (Kenya), Kenya

Insurance does cover negligence.

One insurance loss adjuster told me they pay out on most things but usually try to get out of it if the flight was illegal before it got off the ground e.g.

  • no/expired license or medical
  • no/expired CofA
  • hugely illegal maintenance status

After you are airborne, any mistake is "at worst" negligence and that is covered

However I was also told that if the claim is huge then they look at it a lot more carefully.

Administrator
Shoreham EGKA, United Kingdom

The Mooney M20 series has a x-wind limit of only 11kts. I think this is because the same type certificate covers all M20s from the original short-body (and short rudder) through the medium and long-body variants.... However modern Mooneys regularly cope with 20+ kt x-winds....if indeed I was limited to 11kts I would only be able to operate out of Aberdeen about 50% of the time!

I thought about starting a new thread, but my question is: who actually limits themselves to the demonstrated value?

EGPD / OMDW / YPJT, United Kingdom

If this was a real limit, it would be very... limiting.

I flew to Crete this February and I had a 90 degree crosswind of 25-30kt. That wind was everywhere and it was stronger than forecast. What should I do? Ditch in the sea into the wind?

A strong crosswind is not that dangerous, what is dangerous is a strong gusty wind.

Indeed! :) but would you takeoff in those same conditions?

EGPD / OMDW / YPJT, United Kingdom

I thought about starting a new thread, but my question is: who actually limits themselves to the demonstrated value?

We poor souls who have to make a living from flying do. In our operating manuals we have company and aircraft specific limitations that are based on the demonstrated values of the manufacturer and further reduced for wet/contaminated runways. Bust those limits and the bill is on you if you break something ("gross negligence" the insurer will call it) - and of course you can go looking for a new job. But as usual: When nothing happens, no questions will be asked (unless your RHS colleague reports you, which some of them actually do) so in the end it's one of those solitary decisions that stripe number four throws onto you.

EDDS - Stuttgart
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