I'm hoping someone might be able to provide some up to date clarity on the use of wind on P Charts when it comes to Ambient and Forecast Conditions. Below are a few extracts from the latest copy of the CPL Performance Textbook.

Page 32
2. Always allow for wind for both take-off or landing as given in the question text. Whether the
wind is forecast (for the destination) or actual (for the take-off), always allow for it. If the wind
is at an angle to the runway direction, check the cross-wind, tail-wind or headwind component
having regard for cross-wind or tail-wind limits on a particular runway.

Page 56
For the take-off use ambient conditions. They will have to be supplied by the examiner.
For the landing, you use forecast conditions.

Page 58
Remember whenever you need to use a TAF to establish a landing weight performance limit, it
makes sense to use no wind on the Landing Chart. You may however, use the longest runway
if you have more than one to choose from.

When it comes to each of the P Charts, the Takeoff, and the Landing Charts, in an exam setting, when and when are we not using Ambient and Forecast conditions for each assuming that either has been given in the exam question text? i.e. When should we be using Nil Wind for each chart?

I think this has changed since Dec 2nd, from my understanding now we take wind as fact whether it's a forecast (TAF,GPWT) or ambient (ATIS,AWIS). Ensure to determine the headwind/tailwind and xwind components before plugging into the chart's also!

I'll leave you to do the wading through the rule books to find the references as that is always a useful learning exercise.

It has long been the practice (and I would not change this regardless of what the "rules" might say unless they become more conservative
... and that is most unlikely ever to be the case) -

(a) if the operation is contemporary, as in about to happen, use the advised wind as it should be sufficiently accurate to be fit for purpose with the caveat that one must still be fairly cautious in variable wind conditions. In the exams, if the examiner says the wind is "such and such" then use it as if it is an actual for the immediate operation.

(b) if the operation is not contemporary, as in somewhere relatively distant in the future, then you don't have an actual wind and the forecast must be considered to be somewhat in the realms of fairytales - destination landing being the usual situation of interest. In this case, we use nil wind on the longest runway. If the forecast wind would give an excess crosswind on the longest runway, also check a suitable runway for which the crosswind is acceptable and the lesser weight of the two is the maximum landing weight for planning. Approaching the destination, revert to (a) and, unless things have got right out of hand, you should not find yourself in a non-conservative situation.

NEVER blindly work on forecast winds being "correct". They certainly may end up being so but you believe them at your peril. Let me give you an example of why you don't blindly believe the forecast, Many years ago, I was flying Electra freighters (wonderful pilot's machine) at Ansett. Fuel restrictions applied due to industrial action. Aircraft came down from Sydney into Melbourne with not a lot of fuel on board. No fuel uplift available at Melbourne. The fuel on board was "about" what we needed for Adelaide so we rechecked the forecast etc (remember this was at 0-dark-30 in the morning) and elected to blast off into the dark.

The forecast cruise wind was, say 20 knots headwind, the actual when we got up there was closer to 90 knots on the nose. All three of us did quite a few PNRs on the way over to Adelaide. Eventually landed with "about" minimum fuel .....

Don't ever let yourself get sucker-baited into trusting your life to a weather forecast. Believe that it is going to be worse ...and then just be grateful if you get pleasantly surprised.

Our little escapade, related above, was pretty tame. Do have a read of this very near disaster. There have been many over the years and that is why older pilots don't trust forecasts with their lives.

www.pprune.org/pacific-general-aviation-...ghlight=f28+fuel+MMA

and please do spend the time having a listen to Harold's re-telling of the tale via the link at post #19. If that doesn't have you sucking buttons off your chair seat cover ... then, perhaps, you shouldn't be looking at flying as a career or pastime.

(Relevant post commented on subsequently deleted by poster. The CASA reference can be linked via this link
www.casa.gov.au/search?keys=changes+to+t...+exams+december+2021
This post left for others re wind technique).

Be aware that your last post appears to have nothing to do with your previous post ? I presume that was your intention ? Or am I missing something along the way here ? The note in the CASA paper does not relate to any changes at all and has naught to do with forecast or actual winds. All it is doing is emphasising an aspect of certification which students should have been told all the way along in the past. Again, this is an unfortunate consequence of the Yates Report and the subsequent binning of all the old charts. In the past this stuff was done transparently for the pilot. Now, it's become a bit of a dog's breakfast since the old certification rules were binned but the operational rules retained.

When allowing for head or tailwind components on the charts, the change in slope of the wind correction lines, accounts for the change in % of the wind.

The 50/150 fudge factor has been there forever and a day. It's just a part of the certification requirements.

The trick to telling whether it is included in a chart is either -

(a) a discontinuity in slope as in fig. 4. This is the "kink" evident in the parametric lines in the wind carpet at the zero wind position. This style of chart is what you will usually encounter in POHs.

(b) a discontinuity in the distance between the wind lines as in fig. 3, again as you transit the zero wind position.. This is the "jump" in the distance between the parametric lines in the wind carpet. This will be the case for any of the old DCA format P-charts which, largely, now have disappeared from view out in the Industry.

If you encounter a chart which doesn't have the factors included, then you would need to include them as part of your using the chart. I can't recall ever seeing a chart without the factors included.