Using a wind component chart on final
I really hope that Gertrude is engaged in a bit of good natured trolling here!
But he is highlighting a major issue I have with the way many pilots think about wind. The right time to think about wind is the pre-landing checks *primarily*. I certainly include consideration in mine, but most checklists don't. That is the time for any deep thinking on the topic, as minor variations as you trundle down final, whilst they can make a difference, happen more rapidly than you are likely to get updates on RT. Plus the instrument the tower are using to determine wind is not (usually) adjacent to your touchdown point.
The reason to throw an approach away from final is that the picture from the cockpit is all going wrong - not any last minute arithmetic. Any pilot who is adequately ahead of the aeroplane should either be comfortable they are well within limits, have already made a decision to go-around, switch runway or divert, or be aware that they are close to personal limits and prepared for the high workload and possible late decision based upon the view out of the window to go around. But they should have all of that sorted in their minds before they turn final - and I'd argue most times before they turn base.
G
But he is highlighting a major issue I have with the way many pilots think about wind. The right time to think about wind is the pre-landing checks *primarily*. I certainly include consideration in mine, but most checklists don't. That is the time for any deep thinking on the topic, as minor variations as you trundle down final, whilst they can make a difference, happen more rapidly than you are likely to get updates on RT. Plus the instrument the tower are using to determine wind is not (usually) adjacent to your touchdown point.
The reason to throw an approach away from final is that the picture from the cockpit is all going wrong - not any last minute arithmetic. Any pilot who is adequately ahead of the aeroplane should either be comfortable they are well within limits, have already made a decision to go-around, switch runway or divert, or be aware that they are close to personal limits and prepared for the high workload and possible late decision based upon the view out of the window to go around. But they should have all of that sorted in their minds before they turn final - and I'd argue most times before they turn base.
G
Last edited by Genghis the Engineer; 15th Aug 2017 at 08:18.
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I've just done a quick route plan on Runway HD based on Perth 21 runway at 60 knots. Current wind is 250/15. Magnetic track is 222deg. Which would amount to a crab angle of 12 deg.
This app uses true track converted to magnetic heading so is 3deg incorrect.
All that is required is the runway magnetic track converted to current wind corrected mag heading at landing speed. This would be done well before final.
Alternatively. Know in advance what the pilot's or aircraft's max crab angle is and watch the compass/DI on final for excessive difference to runway heading, and go somewhere else as required.
Faffing about with mental arithmetic and charts on final is nonsense.
I've forgotten whether runways are in magnetic or true, or is that wind directions?
This app uses true track converted to magnetic heading so is 3deg incorrect.
All that is required is the runway magnetic track converted to current wind corrected mag heading at landing speed. This would be done well before final.
Alternatively. Know in advance what the pilot's or aircraft's max crab angle is and watch the compass/DI on final for excessive difference to runway heading, and go somewhere else as required.
Faffing about with mental arithmetic and charts on final is nonsense.
I've forgotten whether runways are in magnetic or true, or is that wind directions?
Runways are magnetic (well, in most parts of them world).
Winds given by ATC or on an ATIS are magnetic, met winds (as seen in TAF/METARS) are True....
Do agree with your comment about faffing about with charts on finals...
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The wind that you get through METARs, VOLMET, ATIS, from ATC, or whatever, is merely confirmation of something you should know already. And a chance to detect any deviations.
I've just done a quick route plan on Runway HD based on Perth 21 runway at 60 knots. Current wind is 250/15. Magnetic track is 222deg. Which would amount to a crab angle of 12 deg.
This app uses true track converted to magnetic heading so is 3deg incorrect.
All that is required is the runway magnetic track converted to current wind corrected mag heading at landing speed. This would be done well before final.
Alternatively. Know in advance what the pilot's or aircraft's max crab angle is and watch the compass/DI on final for excessive difference to runway heading, and go somewhere else as required.
Faffing about with mental arithmetic and charts on final is nonsense.
I've forgotten whether runways are in magnetic or true, or is that wind directions?
This app uses true track converted to magnetic heading so is 3deg incorrect.
All that is required is the runway magnetic track converted to current wind corrected mag heading at landing speed. This would be done well before final.
Alternatively. Know in advance what the pilot's or aircraft's max crab angle is and watch the compass/DI on final for excessive difference to runway heading, and go somewhere else as required.
Faffing about with mental arithmetic and charts on final is nonsense.
I've forgotten whether runways are in magnetic or true, or is that wind directions?
Admittedly there are countries where the magnetic-true variation is massively more than 3 degrees, but none of them are in Northern Europe this year.
G
I never realised working out the crosswind component was so complicated!
The wind might technically be within "limits" but you might get on the approach and have doubts about whether it is safe to land so act accordingly!
CRAP checks? I don't know how I've managed without these "painting my numbers" mnemonics for years.
The wind might technically be within "limits" but you might get on the approach and have doubts about whether it is safe to land so act accordingly!
CRAP checks? I don't know how I've managed without these "painting my numbers" mnemonics for years.
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Also if 3 degrees makes any appreciable difference to whether you're within wind limits or not, then frankly you shouldn't be flying !
Admittedly there are countries where the magnetic-true variation is massively more than 3 degrees, but none of them are in Northern Europe this year.
G
Admittedly there are countries where the magnetic-true variation is massively more than 3 degrees, but none of them are in Northern Europe this year.
G
Agree 100% with your comments though. No-one should do continue/go-around decisions based on silly xwind calculations, which are nowhere nearly accurate anyway, when on final. If it looks good, continue. If it looks like it won't work, go around.
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The worrying part here is that you make decisions based on ATIS/AWOS/tower given wind.
Are you really saying you wouldn't make a certain decision
if say, tower reported wind is significantly outside your and/or your aircraft's crosswind limit ....
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Thirty years in control towers and not once did I have an aircraft go around due to a reported crosswind. They all continued and made their own decision based on the aircraft's handling, usually very short final.
Ok thanks for that, so it's a case of "if it looks/feels alright" it is regarded as acceptable to press on and land, regardless of what the tower reports ( and is perhaps on the tapes..?
Last edited by wiggy; 16th Aug 2017 at 10:08.
The pilot is the commander of his aircraft, and responsible for both good and bad decisions. The tower is only responsible for passing information and in some cases, giving permission or instructing a go-around because of external factors. No controller anywhere in the civilian world has however any say in whether a particular approach is safe or not from the perspective of aircraft handling and performance. That decision is absolutely and completely ALWAYS with the pilot.
G
Last edited by Genghis the Engineer; 16th Aug 2017 at 10:51.
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Let's not forget that the original post is from a student pilot.
Students are trained to fly with an accuracy of a few minutes of arc, or at least try to.
Picking the wrong answer in the Nav written exam may be one degree different to the right answer, but will fail the question. So the question is understandable.
Students are trained to fly with an accuracy of a few minutes of arc, or at least try to.
Picking the wrong answer in the Nav written exam may be one degree different to the right answer, but will fail the question. So the question is understandable.
