Do you use headwind/tailwind when calculating takeoff/landing distance?
Posted by DTplayers@reddit | flying | View on Reddit | 20 comments
General Aviation. I was taught and continue the practice of calculating takeoff/landing distance assuming zero wind. The idea behind it from my understanding is that your numbers will be a worst-case scenario for wind (assuming you aren't landing in a tailwind). If the winds ever die out or change, you won't have to recalculate.
However, seeing that almost every single TO/LDG performance chart includes headwind/tailwind factors, how many people use this and why?
Wedge_Donovan@reddit
Yes, because it causes takeoff and landing distance to vary greatly...especially as you move up into bigger airplanes.
DanThePilot_Mann@reddit
Obviously not GA, but my airline runs all numbers assuming zero wind, unless we have a tailwind. Only time headwind credit is applied is if we cant make it based on no winds
Wedge_Donovan@reddit
Yes. I should have clarified for tailwinds. Same for the bizjet I fly.
mountainbrew46@reddit
Same for us. By default we take no credit for a headwind and 150% of the penalty for the tailwind. We have the option to take 50% credit for a headwind if we need it
DTplayers@reddit (OP)
That's actually very interesting. Do you mind me asking which airline you fly for? Just curious if this varies by operator.
DanThePilot_Mann@reddit
At a US regional on the CRJ, other CRJ fellas can chip in
xtalgeek@reddit
I'm not taking off or landing with a tailwind component. So zero wind planning is fine for any eventuality.
taycoug@reddit
I felt the same way until I was based at Boeing Field for a while. They operate the same direction as SeaTac no matter what so occasionally the only way in/out involves tailwinds.
VileInventor@reddit
The PoH says what to add or subtract for what amount of tailwind or headwind or runway condition
Big_Assignment5949@reddit
Depends if you want a conservative answer or an accurate answer.
Like the guys in here said, sometimes you want a conservative answer. Flight planning is a good example. When you can't take off with a conservative answer, you try again with a more accurate answer. I'm not going to cancel a flight because I can't take off while ignoring a 7 knot headwind, but I might ignore it to start and see if I can take off with comfortable margin.
BagOfMoneyNoChange@reddit
Zero wind for planning (or tailwind if needed at some airports where you may be expected to depart with a tailwind). Actual wind for performance when it's time.
imblegen@reddit
This is how we did it when I was dispatching for the 121 charter I used to work for.
Apprehensive_Cost937@reddit
Actual wind. If it's variable and/or gusty, then the worst case combination.
-burnr-@reddit
Just a correction, 10 knot tailwind (which is the max for just about every aircraft I've ever seen performance charts for) would be the 'worst case scenario', not a calm wind.
DTplayers@reddit (OP)
Thanks for the correction, yeah I should have clarified that I was assuming you could always use the opposite runway to get a headwind, but that's not always an option.
old_flying_fart@reddit
There are one-way runways.
There are runways that are steep enough (it only takes a 1% gradient) that you need to decide 'uphill with a headwind or downhill with a tailwind?' when taking off.
mirassou3416@reddit
I have a TR182 and don't calculate for headwind because that's just a helper. I can't remember ever taking off with a tailwind. I've landed with a slight tailwind but only on really long runways. In my AC a few knots is really noticeable but in a TR182 really anything is manageable unless it's a really short field. The shortest airport that I've landed at was 2240 but I've once landed at a home airport HEF with a 40kn headwind and I landed within a couple hundred feet easily making the first turnoff at around 1300 feet
mbgalpmd@reddit
Non-GA, but airlines:
Normally, it's plug in the ATIS figures to the performance software and try and choose a flap/autobrake setting that achieves what i want: minimising landing configuration drag to reduce fuel burn; exacting landing distance for minimum runway occupancy; using idle reverse thrust for fuel saving; exiting the runway at a location that suits expected taxi routing.
I'll have a glance at zero wind landing distance in a scenario where the runway isn't overly long and the wind conditions are likely to change from the ATIS. But that's only to insulate myself against a pointless go-around if the wind shifts.
hayesjaj@reddit
It depends on the situation. Home field with light payload? No. High density altitude airport with family on board? You bet.
rFlyingTower@reddit
This is a copy of the original post body for posterity:
General Aviation. I was taught and continue the practice of calculating takeoff/landing distance assuming zero wind. The idea behind it from my understanding is that your numbers will be a worst-case scenario for wind (assuming you aren't landing in a tailwind). If the winds ever die out or change, you won't have to recalculate.
However, seeing that almost every single TO/LDG performance chart includes headwind/tailwind factors, how many people use this and why?
Please downvote this comment until it collapses.
Questions about this comment? Please see this wiki post before contacting the mods.
I am a bot, and this action was performed automatically. If you have any questions, please contact the mods of this subreddit.