xwinds and gusts
 

Our aircraft limitations manual specifies xwind limits on dry and wet runways but no mention is made concerning gusts? If the mean wind is within the limits (just) but the gusts exceed the limits what are the legal limits as far as JAR OPS is concerned?

X wind limit= All Steady and Half Gust component (ASHG)

rwy 18
wind 150/20 gust 30

Steady Comp=10 kts
Gust component= 30-20=10 kts

X wind = 20

In the 737 300-900 it states in the manual in limitations (including gusts) So gust is incl.

So if the wind were ....all across 28 gusting 45...you would not take off due to wind being out of limits ??

You sure about that?

Yepp,thats what it says in limitations (including gusts) so that would be over the 35 Kt. on dry runway, and no go.

aircraft used to be certified for xwind landings with only the mean wind component. since a little recently (can't remember when), they're certified with the gust

ex: A320 : ldg xwind max = 33kts without gusts
A318 : dg xwind max = 38 kts including gusts

the plane is a little different but mainly it's the certification rules that have recently changed

seb

Ausbus

I was thinking exactly the same. When I find out, which I will, it's not in our manual either btw, I'll post it here.

Our 747-200 manual says specifically, "CROSSWIND COMPONENT LIMITS (Peak Gust)".

Our 747-400 manual says, "Maximum Demonstrated Crosswind Component
(PEAK GUST, Knots)".

Airplanes, certifications, or airline SOPs may vary...

yep, our 744 manual definitely has x-wind limits based on gusts included.

Once those guidelines make it into the airline operating manual, though, they become limitations, even if they are the same numbers as Boeing's "guidelines."

I've checked now.

For the ERJ-145 and the airline I fly for, it's in Limitations at 30Kt

So on a 20/02 Rwy,

290/30 is legal and the limit.

290/31 is out of limits, so don't land or if you do and it doesn't go as well as you expected, expect limited mercy from the company

But 290/ 29-49 is legal. Go around if more than 30 Kts at the moment of landing.

:confused:

The Aircraft Flight Manual (AFM) will contain a figure qualified as a “Maximum Demonstrated Crosswind”, it will appear in the “operational limitations” section only if it is actually considered limiting for either take-of or landing, or for some other reason, such as autoland operation. In the latter case a descriptive clause will accompany the figure. However, the maximum demonstrated crosswind may not appear in the limitations section, leaving one to ponder what is the actual limit?

How this situation arises can be seen by examining the certification process. JAR 25.237 states that – A 90°cross component of wind velocity, demonstrated to be safe for take-off and landing, must be established for dry runways and must be at least 20 knots or a fifth of reference stall speed in the landing configuration (VSR0), whichever is greater, except that it need not exceed 25 knots.

In reality, during the certification test flight process, the manufacturer searches for locations and conditions that not only meet the regulatory requirements but also demonstrate the operational capabilities of their aircraft – that after all is economic sense. A test pilot who flies multiple crosswind approaches, developing technique to near perfection, will obviously be able to handle greater winds than most operational pilots in a variety of situations. Therefore, when a demonstrated crosswind is high, there needs to be some factoring applied to cater for everyday situations. A manufacturer may therefore publish crosswind landing guidelines in various manuals available to the operator.

Both our FHBs (747-200 and -400) refer to the wind limits as such -- "limits" for all cases. Where "max demonstrated" is listed, it is followed by "(Peak Gust, [airline] Limits)"; there is no question as to whether they are considered limiting.

I witnessed an Air Italy 757 on Finals at MAN a few years ago, It was the 'Scariest' Landing I have ever seen.

The conditions were very Hazy, the Xwind was blowing near the end of
R24R it was 29+ Kts, I had my scanner on and the Haze made the Landing as easy as doing a maths exam in the dark!

The 757 flared at the normal t down point but suddenly a 'severe' Xwind lifted the 757 onto it's port wingtip - missing the runway by inches!

immediately the PF corrected, pulled back and elected to Go- around after nearly touching down and taking off the port wingtip or subsequently the wing!


MAN ATC asked the 757 what was the reason for the Go-around, and the reply was 'an obvious and safe choice in the conditions' even though it was obvious that the reason was of the Xwind ATC have to ask the question.

The 757 made it's 2nd and last approach and it flared and landed alot earlier subsequently without incident.

I was surprised to see that ATC had not asked the AFS to stand by the runway?

I was certain the 757 was going to 'Flip' over landing in the Xwind that day, But fortunately not.

Regards.