Maximum headwind/crosswind component
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Maximum headwind/crosswind component
Has anyone heard of an airline that has an SOP maximum headwind component for takeoff or landing?. .. .Recently, during some 'hangar flying', a colleague claimed that after landing on a very windy day (60 knots +)in Vienna, he found that the local airline, Austrian, was grounded due to the wind conditions.. .. .I think that it does make sence to have such limitations imposed, although I have honestly never heard of them. Personaly I doubt if I have ever experienced more than 45 knots, and that was probably on he nose. It would be pretty much 'cowboy attitude' to land in 60 knots+ without having even ever experienced such demanding conditions. So many accidents/excursions/undercarraige collapse etc occur in these conditions. <img border="0" title="" alt="[Frown]" src="frown.gif" /> . .. .My second question is for Airbus pilots. Do your companies have a maximum crosswind component or a maximum demonstrated crosswind component. Our company has the latter, but apparently JARs require a maximum to be specified, so we need to revise our SOPs.. .. .However, the FCOM demonstrated crosswind component for the A320 is 29kt gusting 38kt for takeoff and 33kt gusting 38kt for landing. I would like to know what your respective companies have selected as a maximum crosswind component, the steady wind or the gust?. .. .Thank you. .. .Ekola
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Hopefully most successful landings will be followed by a taxi to stand. This is often where the limitation lies. We don't have a maximum headwind component, but we do have an absolute maximum wind: 50 knots, for taxi.
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I operate a Dash 8-311 (twin turboprop) and there is a Maximum Ground Manoeuvring Wind Speed of 65 knots specified by the manufacturer for the type.. .I imagine it is stability and/or nose steering related, but I'm not sure.. .. .Anyone who has operated the type in winds of this intensity (only once for me) would remember it as being a distinctly uncomfortable experience.. .. .This limit is independent of the limits specified for aircraft parking, on exposure to which an engineering inspection schedule is specified.. .. .The airline now ceases operations at winds well below this level.
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The crosswind limit is usually stated as a "Demonstrated" limit. The FAA, for instance does not require manufacturers to even state one in their Flight Manual. Look at the DC-9 and the Dornier 328J. The airline can make a limit, and probably would if they were wise, but it is not a requirement.. .The other limit is for ground handling as the wind hits the fin and the nosewheel loses traction. That again could be a manufacturers recomendation or a company imposed limit.. .If the JAR requirements are for the manufacturers to test and certify a limit we will have found at least one thing that the JAR's are good for.. .Line pilots should not be expected to be test pilots.
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Apparently the JARs now require the airline and not the manufacturer to specify a crosswind limit. This is obviously to be derived from aircraft's FCOM. . .. .737's demonstrated crosswind limit for example is 35knots, so it is simple to set this as a limit in the airline's SOPs, however Airbus 320's manual defines a demonstrated crosswind limit for landing as 33knots gusting 38knots, and my dilema is (to avoid being a test pilot) whether to accept the 33knots as a maximum or rather the 38knots.. .. .Regarding the maximum headwind component, I am glad to hear that some airlines have imposed a wind limit of 50 knots to operate. . .. .I am especially interested in A320 operators. Do any impose a maximum headwind component. The only wind limit by the manufacturer is for door operation, 65knots. It would also be interesting to learn what operators of other types do, too.. .. .Ekola
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.....just came across this site to drive the point home! . .. .<a href="http://www.kmpilots.com/Articles1/hapag_lloyd_netherlands_boeing_7.htm" target="_blank">http://www.kmpilots.com/Articles1/hapag_lloyd_netherlands_boeing_7.htm</a>. .. .Ekola
Speedbird48. .. .Not sure exactly what you mean about the FAA and Flight Manuals. .. .FAR Section 25.237: Wind velocities.. .(a) For landplanes and amphibians, a 90-degree cross component of wind velocity, demonstrated to be safe for takeoff and landing, must be established for dry runways and must be at least 20 knots or 0.2 VS0, whichever is greater, except that it need not exceed 25 knots. . .. .Normally, a datum 'established' under FAR 25 is recorded in the Flight Manual.. .. .Or do you mean 'they do not specify a limit'? In which case I agree...
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If I may offer a few observations. .. .(a) generally the reported wind limits will be those which the manufacturer conveniently found, provided that they are not less than whatever minimum values are set by any particular design standard. It is quite usual for the maximum values flown to be found "not limiting" .. ie in the opinion of the test pilot(s), the aircraft could be flown in conditions more critical than those found. I think it nice to treat this as a limit in the absence of further data determined by someone else much more adept than I at evading criticism at the accident enquiry .... .. .(b) sometimes the aircraft is limited by wind. For instance, some years ago, a US light aircraft came to Australia with an "adequate" (per design standard) demonstrated crosswind value but which, in view of the Australian NAA's policy to make the maximum demonstrated the maximum allowable, was a bit useless for local operations. I was involved in the test program to up this a bit and, to our surprise we found that the particular aircraft model was quite severely limited and we only managed to push the value up to, as I recall, something in the vicinity of 18 knots before we got to the area of frightening ourselves.. .. .(c) sometimes an excessive tailwind can present problems. Although I was not involved with the program, a TP colleague related a tale of one aircraft which had a tendency to pitch up at the start of the takeoff roll in strong tailwind conditions. .. .(d) operations in very strong winds pose a concern with the near ground boundary layer and shearing wind variations associated with nearby terrain. .. .(e) many runways have significant windshear or similar problems associated with terrain effects in particular wind conditions. .. .(f) as one contributor has noted, taxy capability may become limiting. .. .Mind you, the apocryphal tales of some of the old school DC3 operations into the Australian aerodrome at King Island in horrific winds still make very entertaining hangar yarns.
Don't know about 'buses but Boeings usually have a max windspeed for operation of the doors and airstairs, which a prudent operator could take as a limit for the whole aircraft; no point taxying about if the doors can't be opened.. .. .Not many people know that there is also a design limit for the slides ( typically 25 knots), above which their correct operation is not assured. There are occasionally pictures of deployed slides having been blown back over the top of the fuselage etc. Yet amazingly (to me anyway) aircraft are allowed to operate in winds above the slide design speed, or conversely such slides are certificated for installation on aircraft where the aircraft is operated above the slide design speed. Limiting aircraft to 25 knot winds would be somewhat restrictive, so why aren't slides required to be improved?
JT wrote:. . </font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> (a) generally the reported wind limits will be those which the manufacturer conveniently found, provided that they are not less than whatever minimum values are set by any particular design standard. It is quite usual for the maximum values flown to be found "not limiting" .. ie in the opinion of the test pilot(s), the aircraft could be flown in conditions more critical than those found. I think it nice to treat this as a limit in the absence of further data determined by someone else much more adept than I at evading criticism at the accident enquiry ... </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">A fair point, but very limiting in some cases, as it seems the manufacturers can choose to write the lowest possible value in the POH. For example the Mooney 201 (Vs0 55 kt) has an 11 kt demonstrated crosswind component, exactly 20% of Vs0 which is the lowest value permissible. The Mooney has never been a nice aircraft to operate in a crosswind, but an 11 kt limit would render it almost completely useless in many places.
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This relates to my other point about revisiting the crosswind. . .. .With some recent FAR23 models, a low crosswind value is a problem .. while the Mooney was not the aircraft to which I referred, the same sort of situation existed with the particular machine.. .. .However, for any aircraft which is deemed too limiting (in any regard .. crosswind or whatever) my over-riding concern is that one is better off reviewing the limitation as part of a formal test program rather than just operating in an ad hoc manner. . .. .Either the limit can be extended, or it can not .. the design standards are there to capture the expensive lessons of history and we would be a little silly to circumvent those lessons.. .. .Unfortunately, there are various problems which can arise in aircraft handling which are not generally known outside the flight test and certification community .. one of the reasons we have formal certification programs run by experienced and competent people ... to try and find the more hazardous problems before they have a chance to bite the trusting line pilot.. . . . <small>[ 12 March 2002, 22:23: Message edited by: john_tullamarine ]</small>
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a maximum wind limit on ground makes sence because it is likely to have the wind on the tail during taxi and aircraft do not like this. A F100 has suffered damage on the tail some years ago due tailwindgust on stand and imagine you get the damage during taxi-out...
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Someone who knows a lot more about this than I explained to me that the 'demonstrated crosswind component' is a purely structural limit, not an aerodynamic limit at all. . .. .It means that the landing gear will stay on in an uncorrected crosswind landing.. .. .One night, on take-off from Biggin RWY21, I found another limit in a 45 knot headwind: my eyeballs were bouncing so much it was impossible to read the instruments, this was in a cabin class twin near gross.
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I would have thought the reasons for headwind limits are self-evident:. .. .1)Assume a Vref 0f 130, and a headwind of 150 (for whatever reason...typhoon?)..which way would you flare, nose up, or nose down?. .. .2)how would you see the runway at minimums, on a, for once, REAL 'back course'?
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Landing at EHAM once with steady wind at 66kph, but right down the runway. Later, at a remote stand, facing into the wind, it took three people to fully open the L1 door! <img border="0" title="" alt="[Roll Eyes]" src="rolleyes.gif" />
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Another reason for a limit being imposed can be risk of control cable stretch. In one company, an ATP with only internal control locks can be exposed to winds of up to 52 knots before eng inspection is required. However, if external locks are fitted, only if the wind gets over 65 knots is engineering inspection required.
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Ekola: . .As you are interested in A320:. .For TO we have no headwind limit, the headwind limitations we have are for the automatic approach and the automatic landing (automatic approach means following the ILS on a/p and autothrust). Also there is a difference between A319/20/21:. .. .A321: autoapproach 40 kts headwind; autoland 30kts headwind. .A320: autoland (managed speed) 30 kts headwind; autoland (selected speed) 20 kts headwind. .A319: autoapproach/landing both 30 kts headwind max. .. .For manual flight there are no headwind limitations, except offcourse common sense.