crosswind limitations

[tom747uk]

We have all experienced the strong winds that prevailed throughout Europe over the last couple of weeks. I myself was flying into Dublin the weekend that the unfortunate md11 went off the runway. At times the winds exceeded 50 kts. A lot of aircraft diverted but a lot landed and took off.. .Boeing only give demonstrated crosswind limitations which are not AFM limits of 35 kts. on the 737s. Its up to flight ops. to issue their own crosswind limitations in their ops manual as part of SOPs and ROPs which is passed by the aviation authority in each country.. .I’m not attacking anyone here and I know that it is up to each pilot to access the situation as it happens but are some airlines not using any form of crosswind limitations? Is ATC helping them out by asking, “what winds do you need?”. .Are some airline pilots under pressure from their management to land and take off and not to divert because they have to do quick turnarounds to make profit.

I was told that the wind readout ( with max gust) in the tower in Dublin is held for 10 mins. . .Anyone like to comment !!!

[puddle-jumper]

The BAe 146 has the same 'Maximum Demonstrated' note next to it's crosswind limitations. Needless to say our company has tried to play the line 'that means there is NO actual crosswind limitation and it is up to the individuals ability'. Personally, if BAe come up with a max. demonstrated of 35kts then who am I to argue. Their test pilots are probably alot better than I am and they probably don't have 100+ passengers sitting behind them when they demonstrate it! . . Makes me wounder what the court of inquiry would say? 'So the manufacturer has demonstrated what they think the max. X-wind should be but you decided to use a higher one'!!!!

PJ

[AAL_Silverbird]

Here in the United States the NTSB has just told us that we basically can’t us our rudder so I guess if you accept any crosswind on landing you just became a test pilot. Three hundred million takeoffs and landings since the jet was introduced and not one vertical stab has come off until now. Pilot error . . . yea right!

[EGGW]

Well having flown in the windy conditions as well in the last 2 weeks, i have thought one heck of a lot about the X-wind limits. Many people say these are the demonstrated x-winds that the test pilots managed to find during certification, and the actuallimits maybe higher. Like the poster above, at the court of inquiry would the fact that you tried to do some test flying with pax. onboard really go down well, i think not. http://www.stopstart.fsnet.co.uk/smilie/jpshakehead.gif. .AAL Sliverbird, so how do you do X-wind landings these days, just crunch it on???? :) Personally i always try and get rid of all the drift with rudder, and it worked a treat for every landing in gusty/windy conditions in the last few weeks.

[Oliver James]

ATCO LL.

A very relevant topic.

When the manufacturer gives Maximum demonstrated, do they qualify that with the conditions prevailing at the time? A steady 35kt crosswind, during daylight on a dry runway must be different to mean 35kts, gusting 45, wet runway at night?

20 years ago, the crosswind limits for 23 at Heathrow used to be 15kts. Then about 10 years ago, as the need for stands became desperate, they took away its ILS and built the Whisky's. Using 23 means clearing them, which can take up to 3 hours and it can (but not always) impact the landing rate slightly. To discourage its use the limits for 23's promulgation were increased to a mean crosswind component of 25 with no allowance made for gusts, wet conditions or night time. There has been one occasion when a 747 was refused 23 on a nasty, wet night (because it didn't meet the critera) and then blocked 27R. Big delays ensued.

We have used 23 quite a bit recently but there were other times, in awful conditions, when we didn't. It seems to me that these limits expose us to greater risk than is prudent and they ought to be more flexible to take account of the particular circumstances pertaining. If we lose one of the mains the knock on effect of hours of single runway ops. will be felt long after.

It feels contrary to the good aviation practice that we are all supposed to be striving for. <img src="confused.gif" border="0">

[Christopher James]

Agreed.

[NorthernSky]

Regarding ATCOs asking 'What wind do you need?', look into the Air UK F27 crash in the Channel Islands to see the benefit of the tactic. (A 'crash', though only a minor 'crash').

Demonstrated crosswind components relate to a particular level of handling qualities. These qualities are decided/assessed by the flight test team, so if you go beyond them you are effectively saying you are better placed to judge these matters than the flight test team. Are you? If you are, you should be living a better/quieter/more rewarding life as a test pilot ;-)....... Home every night.....

The ten minute period mentioned above relates to METAR criteria for wind assessment, and bears further consideration. If you want to know the real wind, ask ATC for the 'instant' wind, but bear in mind that such considerations as anemometer siting will have an influence on reports.

Oh, and don't build airports on hills and claim that they're safe!!! (EGGW take note).

[Data Dad]

Working as I do at what has become known as Ice Station Zebra, our combination of short N-S runway and prevailing west winds means that it doesnt have to be particularly windy for pilots to start getting a bit twitchy! (factor in the hills, rain, snow makes for an interesting time!)

Most (All?) British Airport ATC units now give (sorry are required by SRG) to pass the surface wind in its "averaged" form - ie: the mean direction and speed over the preceding 2 mins with any gusts of +/- 10kts greater than the mean in the last 10 mins reported as max or min.

SRG have decreed that we are only allowed to pass the instant wind when specifically requested by a pilot. I can count on the fingers of one hand the number of times I have been specifically asked for that! If you make a last minute request for a "wind check" on short final as you are bouncing around the sky, the odds are it will sound very similar to the one you were given when cleared to land - cos the mean doesn't vary wildly :)

The Guernsey accident report mentioned above makes interesting reading - apparently the Guernsey ATCO's can at THEIR OWN discretion, pass the instant wind when the mean goes above 20 kts (I'm doing this from memory - maybe 25kts) Would our own SRG please take note!

DD

[LRdriver]

IRC then max demonstrated xwind becomes max allowable xwind in accordance with JAROPS..