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Landing above Flight Manual max demonstrated crosswind limit

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Landing above Flight Manual max demonstrated crosswind limit

Old 7th Oct 2016, 02:17
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Landing above Flight Manual max demonstrated crosswind limit

Question.
Discussion arose re Metro AFM max demonstrated cross wind limit for take off or landing of 25 knots. Let's suppose a pilot prangs the Metro while landing above that AFM cross wind component because of a company policy that authorises such action. Who then wears the subsequent legal responsibility? The pilot, the company or CASA for approving the company limit which is higher than the AFM advice?
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Old 7th Oct 2016, 02:53
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max DEMONSTRATED crosswind is exactly that, max crosswind component the aircraft was demonstrated to land in during certification.

It appears that Crosswind maximum is a grey area, some think its a hard limit not to exceeded ever, and others, like myself, see it as above, max demonstrated, and crosswinds that are higher can be handled by the aircraft.
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Old 7th Oct 2016, 02:55
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A very good question.
In a similar vein, imagine a company policy that dictates that the PIC does not need to carry sufficient fuel for an alternate, and CASA then approves that policy, and then a Pilot follows the company policy and ends up putting a jet into a paddock due to an unforeseen problem at destination.
I would imagine that everybody would be pointing the finger at the PIC whilst the policy makers are diving for cover.
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Old 7th Oct 2016, 03:11
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max DEMONSTRATED crosswind is exactly that, max crosswind component the aircraft was demonstrated to land in during certification.
It appears that Crosswind maximum is a grey area, some think its a hard limit not to exceeded ever, and others, like myself, see it as above, max demonstrated, and crosswinds that are higher can be handled by the aircraft.
Ditto!

Depends on the experience of the pilot and their demonstrated abilities.

Remembering that this is a GA forum - I have landed the V-tail in conditions well above its maximum demonstrated X-wind of 17 kts, ie 25 kts gusting to 30 kts all x-wind. The end result was one flat-spotted tyre, but it was close to its use by date and a small price to pay for being safely on the ground in rapidly deteriorating conditions that I was not keen to climb back into.

And if I had pranged it - well that's what insurance is for isn't it?

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Old 7th Oct 2016, 04:08
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Demonstrated is demonstrated. It's not a limitation.

However the onus is then on the pilot if something untoward occurs, to justify their decision to operate as a test pilot. It is preferable for good flight planning and operational decision making to mitigate this in the first place.

No limitation or demonstrated flight regime excludes the declaration of a mayday or pan pan if circumstances dictate.
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Old 7th Oct 2016, 04:18
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And you can guarantee that if the insurance company could prove you tried to land in a xwind that exceeded the figure in the AFM and subsequently bent the aeroplane in the process, they would be pretty quick to deny liability..!
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Old 7th Oct 2016, 04:26
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And you can guarantee that if the insurance company could prove you tried to land in a xwind that exceeded the figure in the AFM and subsequently bent the aeroplane in the process, they would be pretty quick to deny liability..!
That's what I woulda thought.
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Old 7th Oct 2016, 04:42
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If the pilot was not the owner/insured the claim would be paid...
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Old 7th Oct 2016, 04:59
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Insurance companies routinely deny claims or offer a percentage of the insured amount as a first offer in the hope the claimant will accept their decision. They do it all the time and it is factored into their business plan that they will actually avoid paying some legit claims because the other party can't or won't take them on.

It is reprehensible behaviour but what do you expect from insurance companies.

Pilots tend to use the "insurance won't pay" thing as an excuse to not do a lot of things or to criticise someone else who did something.

I tend to think that we get paid the bucks to make the decisions and as long as the decisions are based in sound reasoning and a reasonable assessment of the circumstances then you would be ok, even if they did try it on the first time. Certainly the law of the land backs up the commander as the sole decision maker.

I don't abide by the "I did it that way because it was the way my training captain told me" or "that's what we always do" defence, as the captain of an aircraft, or crew member of a multi crew aircraft has a responsibility to use their head and think about the ramifications of their decisions before leaping into action.

Doesn't mean we can't learn something from an event that didn't quite turn out as hoped or even determine not to do something again even if it turned out ok this time.

In this discussion, the max demonstrated crosswind figure is exactly what it says in the wrapper, this is the maximum crosswind we tested this machine in. We don't know if it is because their theoretical testing/analysis said that you go 1 knot over and it turns into an uncontrollable ball of shit, or whether they went to the testing airfield for a weeks flight test campaign and the best they had was what is in the book.

It also doesn't mean that the person hanging onto the aeroplane is capable of managing the airframe in that maximum crosswind condition. It may well be that the aeroplane can do 45 knots but the pilot can only reasonably manage 35, in which case the captain makes an operational decisions that says above 35 knots we are diverting. Similarly as FTDK demonstrated the figure says X but the conditions dictate that I am going to have a go at Y because the alternative is worse.
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Old 7th Oct 2016, 05:27
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I struggled to land a metro in 15 kts of cross-wind because the cockpit was so damn tight that when I pushed the rudder it lifted my other knee enough that it forced me to deflect the ailerons in the same direction as the rudder (i.e. couldn't cross control very much).
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Old 7th Oct 2016, 05:59
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The answer to your opening question, C, is that everyone gets sued, everyone denies liability, the insurance company denies cover, and it all gets sorted out on the steps of the court.

There is an important question as to what "demonstrated crosswind limit" actually means. My understanding is that, at least for landing, it is the crosswind that an aircraft has been demonstrated as being able to land without structural failure, if the pilot applies no control inputs to counteract the crosswind in any way. That is, for an aircraft with a demonstrated crosswind limit of, say, 17 knots, the test pilot has landed with the aircraft pointing straight down the runway but moving 'sideways' at 17 knots, and the undercarriage (and related airframe parts) have withstood the consequential stresses.

Like the good FTDK, I've landed a few aircraft in crosswinds far in excess of the stated crosswind limit. Touch wood I've not had to have a subsequent conversation with my insurer.
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Old 7th Oct 2016, 07:07
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It is the maximum that was required to be demonstrated by the test pilot. I stand to be corrected here but believe it is when there is full rudder deflection at 1.3 times the stall speed.
Otherwise it is relevant if you are working out whether you need an alternate.
As for an insurance claim how are they going to prove the exact amount of crosswind at the exact time the wheels touched at an uncontrolled aerodrome?
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Old 7th Oct 2016, 08:14
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I think the term is "Demonstrated Crosswind".

It isn't listed in Section 2 or Limitations section of the AFM as it isn't a limitation. I'm pretty sure Section 2 of the AFM is the only section that has to have FAA/CAA/CASA approval.

My understanding the Demonstrated Crosswind is the crosswind a pilot with average ability should be able to handle without difficulty.

I'm not sure it relates to control deflections at certain speeds, as Piper seems to use the same figure for a wide variety of aircraft as I think do Cesssna also. It seems to be an arbitrary number that meets the manufacturers purpose

Some operators may have their own company limits.

I don't think an insurance company could refuse cover based on the Demo crosswind being exceeded,

Last edited by 27/09; 7th Oct 2016 at 08:48.
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Old 7th Oct 2016, 08:45
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There were some pretty hairy x-wind landings on 27 at YMML while 16/34 was being widened for the A380. I'm not sure what the max was at that time but it was over 30kts
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Old 7th Oct 2016, 09:58
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Every section of the flight manual required by the regs is required to be approved by the authority. If flight testing determined it to be a limitation then it would be in the limitations section.
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Old 7th Oct 2016, 10:15
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Interesting read on cross-wind ops includes the FAA requirements for calculation of any limitation>>

...stolen from Plane and Pilot mag

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Old 7th Oct 2016, 10:18
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Boeing 777 Limitations, Crosswind 38 kts. demonstrated, a Trans Tasman Operator has a Company Limit of 40 kts... It all depends if the AFM states demonstrated or limit.
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Old 7th Oct 2016, 10:33
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Yes, ^^ that's correct. From the FAA flight test guide AC 23 (GA/commuter):

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.

b. Procedures.

(1) Crosswind.

(a) The airplane should be operated throughout its approved loading envelope at gradually increasing values of crosswind component until a crosswind equivalent to 0.2 VSO is reached. All approved takeoff and landing configurations should be evaluated. Higher crosswind values may be evaluated at the discretion of the test pilot for AFM inclusion.

(3) Taxi Controllability.

(a) A landplane should have sufficient directional control available through the use of nose/tail wheel steering, differential braking (if provided), differential power (multiengine airplanes), and aerodynamic control inputs to allow taxiing at its "maximum demonstrated crosswind" value.
So it is 'performance' information unless it appears in limitations. The assesment is "qualitative" according to the CFRs. The final call is made by the FAA TP who sits in with the company TP for the certification test. Ref AC 23-8C, AC 25-7C, 14CFR 23, and this summary (which applies to transport cat).

What it isn't:

the crosswind that an aircraft has been demonstrated as being able to land without structural failure, if the pilot applies no control inputs to counteract the crosswind in any way. That is, for an aircraft with a demonstrated crosswind limit of, say, 17 knots, the test pilot has landed with the aircraft pointing straight down the runway but moving 'sideways' at 17 knots, and the undercarriage (and related airframe parts) have withstood the consequential stresses.
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Old 7th Oct 2016, 11:10
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Certainly a bit of poetic license used as quoted above.

If that was the case aircraft manufacturers would need a lot more prototypes as they crash them all off during crosswind landing destructive testing !
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Old 7th Oct 2016, 11:19
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Always been a bit of a problem in Oz. Unless things have changed in recent years (and the move across to accepting NAA certifications may be relevant), CASA and its antecedents have tended to view the published crosswind as being a defacto limit. What the case might be at law is not within my field ..

A few points to keep in mind before one pushes one's luck too much -

(a) there may be rudder-limited considerations .. during the flare is not the best time to discover this sort of problem

(b) there may be structural considerations. While there be numerous interesting videos of heavies being landed during OEM FT work with substantial crab still on, that probably is not a good idea in one's average lightie.

(c) the design rules require a minimum crosswind to be covered by the flight test program.

There is no reason why the OEM needs to go above the minimum and, often, the program may just not have found conditions which might, otherwise, have been desirable. For instance, the Rockwell singles had a comparatively low crosswind value. We redid the flight tests in Oz and published a higher (but not all that much higher ..) revised figure which was limiting in the opinions of the TP and FTE (me) on the day.

Have I pushed my luck at times ? .. not saying .. but Miro V (hopefully he is still with us .. albeit at around 90) probably could recall a couple of demolished gable markers at Camden (on separate occasions) due to close contact of the mainwheel kind in the SuperCubs ... I guess that any tug pilot who has operated with SuperCubs can fill in the gaps in my storyline .... then again, it is rumoured that we routinely operated across the flight strip if things became a little too hairy .. all pure imagination, of course ...
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