Gusty winds, crosswinds and landing distances

[JimB]

Just a quick question on landing distances when using half flaps for gusty winds and a possible crosswind. How much do you add to your landing distance when using half flaps? It seems to me that it takes maybe a couple hundred feet extra. Does that sound about right? 

Put another way, I am planning a trip later this week to a coastal airport. Winds are forecast to be 17-20knots gusting to 25-30. Maybe a 45 degree crosswind. The runway is 60' wide and 2900 feet long, no obstructions. If that ends up being the winds when I get there, I'd like to use 1/2 flaps but it's not a long runway (but I certainly wouldn't call it short). Thoughts? 1/2 flaps for the gusts or full flaps for the runway length...

[RobertGary1]

Why are you using 1/2 flaps? I’ve not seen that technique in the poh foe the models I’ve flow. 

[JimB]

Just now, RobertGary1 said:

Why are you using 1/2 flaps? I’ve not seen that technique in the poh foe the models I’ve flow. 

With gusty winds, I use half flaps and a little more speed. It's a normal technique for gusty conditions that I have used in every aircraft and was recommended during transition training. The POH I have just says flaps as required and "Extend flaps as required on final approach to adjust for variations in wind, glide angle, and other variables."

 

[gsxrpilot]

Most of my landings are either with takeoff (half) flaps, or no flaps. When I do use full flaps, I can usually get the plane stopped 200 or 300 ft shorter. So your estimation is about what I see as well. I'd definitely use "less" flaps in gusty conditions.

[HIghpockets]

I usually land with full flaps. The exception is if there is a gusting crosswind equal or greater than 20-25 KTS I will go to 1/2 flaps. Theoretically, it decreases the lateral profile of the airplane to the crosswind. YMMV.

[PT20J]

I use takeoff flaps and add 5 kts in my M20J for landing with a gusty crosswind. This makes the crosswind less in relation to touchdown speed and the lesser flap deployment cuts float.

If the airspeed is bouncing around, I adjust pitch and power as necessary to hold glidepath with the lowest airspeed excursion hitting my target speed. I don’t try for a full stall landing, but I want the airplane tracking straight with the nose slightly high. If it is really gusty, it may take some effort to get the plane in the proper attitude before letting it touch and this eats up runway. So, the landing distance is variable with conditions. I would agree on  adding 200  - 300 feet for planning, but when you get there you have to deal with actual conditions. It’s important to preselect a go around point and not continue the landing attempt if you pass it without touching down.

Also, remember that the Mooney nose wheel steering is rigidly attached to the rudder system, so keep light on the rudders and let the nose wheel center when touching down.

Skip

 

[JimB]

Thanks for the comments. I think knowing the airport and anticipating what the winds will be, I will be using my takeoff flaps. If I'm not firmly planted in the first few hundred feet or so on the runway, I can easily go around. That's the other benefit of takeoff flap landings, the aircraft is already configured for taking off. 

Edited April 26, 2021 by JimB

[GeeBee]

Reduced flaps will result in increased aileron effectiveness. 

 

[bradp]

And increased rudder effectiveness with increased landing speed.  
 

I use half / takeoff flaps for xwind component of greater than 10 kts.  Or if I’m iffy about the “landing assured” status of my approach I’ll keep the 1/2 flaps because there are no configuration changes to be done on the go  

In terms of landing distance and ground roll, I might plan for 10-15% additional distance. Honestly there is usually a quartering head wind component so my ground roll is typically less half flaps gusty day than a smooth day. If I need to think that hard about 10-15% ground roll mattering in windy / challenging conditions, I’ve probably chosen the wrong airport to land at.  

[RobertGary1]

2 hours ago, GeeBee said:

Reduced flaps will result in increased aileron effectiveness. 

 

In 20 years flying my Mooney through the winds in the southwest I’ve never lost aileron effectiveness in the flare. 

[steingar]

Delivering my Mooney for annual last year I had no flaps, they were busted.  3K foot strip, hot and not a lot of wind.  No trouble at all, and I didn't come close to using all the runway.

[Shadrach]

4 hours ago, JimB said:

Just a quick question on landing distances when using half flaps for gusty winds and a possible crosswind. How much do you add to your landing distance when using half flaps? It seems to me that it takes maybe a couple hundred feet extra. Does that sound about right? 

Put another way, I am planning a trip later this week to a coastal airport. Winds are forecast to be 17-20knots gusting to 25-30. Maybe a 45 degree crosswind. The runway is 60' wide and 2900 feet long, no obstructions. If that ends up being the winds when I get there, I'd like to use 1/2 flaps but it's not a long runway (but I certainly wouldn't call it short). Thoughts? 1/2 flaps for the gusts or full flaps for the runway length...

If you nail your approach speed and don't float the extra 5-10mph isn't going to add much to ground roll probably less than 300'. I don't really have a specific formula I use these days.  If I can hold runway heading in a slip on final than it is very likely that their will be less correction needed in the flare.

Edited April 26, 2021 by Shadrach

[RobertGary1]

From factory test pilots. 
 

“My personal opinion was that partial or no flaps flattened the approach angle to the runway, making it more difficult to see the runway environment over the nose to properly judge drift correction. I personally liked the steeper approach angle and better visibility of the runway environment provided by full flaps when testing Mooneys to their crosswind limits.”

 

https://themooneyflyer.com/issues/2013-AprTMF.pdf#page7

[N201MKTurbo]

I've always landed full flaps. I can't imagine why I would land with partial flaps. I've landed in all kinds of winds up to 70 KT gusty cross winds. Any wind will shorten your landing distance, unless you are landing downwind.

Cross winds greater than the stall speed of the plane are a bit easier. You just keep the airplane into the wind and hover down to the runway with zero landing roll. Taxiing on the other hand is another matter all together.

[PeteMc]

@JimBGetting back to the 45 degrees G35 for a minute...

If you're not used to strong crosswinds and gusts up to 35kts, just remember if you're not happy, go around and try it again.  I had one heck of a time the other day with the winds 20 something with G35.  It took a lot of rudder to keep straight.  All was good until I was a few feet above the runway and...   the Gust stopped Gusting!  Dropped and got a good bounce!

It was a nice long runway but this was not a day I was going to try and save it with those gusts.  Second time around I still had to work for it, but the landing was fine.

 

[RobertGary1]

1 hour ago, PeteMc said:

@JimBGetting back to the 45 degrees G35 for a minute...

If you're not used to strong crosswinds and gusts up to 35kts, just remember if you're not happy, go around and try it again.  I had one heck of a time the other day with the winds 20 something with G35.  It took a lot of rudder to keep straight.  All was good until I was a few feet above the runway and...   the Gust stopped Gusting!  Dropped and got a good bounce!

It was a nice long runway but this was not a day I was going to try and save it with those gusts.  Second time around I still had to work for it, but the landing was fine.

 

I've noted that crosswinds in general often go away in the flare in Mooney's. I suspect its just because the wing is so close to the ground.

[Yetti]

I generally land with half flaps.   I have not missed the 3000 foot turn off never and can make the 2000 foot turn off if needed.   There are many 2900 foot strips I fly to.   You will have a head wind so that will shorten the distance.  

The centerline is the centerline so if you are on it, you won't have to worry about the sides of the runway.

This is 3800x60 with a gusty day.

I fubared the 1st approach.

The second one I was still scrubbing energy in the air above the runway, so landing almost midway down the runway, but since I scrubbed all the energy in the air, the rollout was very short.

[jaylw314]

Half flaps is probably fine, even with the higher airspeed, your groundspeed will be lower because of the crosswind correction.  90 degree crosswind, you're still losing some of your forward groundspeed fighting the crosswind, and that may make up for the small difference between full and half flaps

Edited April 27, 2021 by jaylw314

[jaylw314]

12 minutes ago, Yetti said:

I generally land with half flaps.   I have not missed the 3000 foot turn off never and can make the 2000 foot turn off if needed.   There are many 2900 foot strips I fly to.   You will have a head wind so that will shorten the distance.  

The centerline is the centerline so if you are on it, you won't have to worry about the sides of the runway.

This is 3800x60 with a gusty day.

I fubared the 1st approach.

The second one I was still scrubbing energy in the air above the runway, so landing almost midway down the runway, but since I scrubbed all the energy in the air, the rollout was very short.

That's a cool video overlay, what device does that come from?  I've seen it before and can't remember

[Yetti]

2 minutes ago, jaylw314 said:

That's a cool video overlay, what device does that come from?  I've seen it before and can't remember

Sony Action cam.   Sony editor you have run it through.   I need to see if I can find some shorter strip videos.

 

[Hank]

29 minutes ago, Yetti said:

I generally land with half flaps.   I have not missed the 3000 foot turn off never and can make the 2000 foot turn off if needed.   There are many 2900 foot strips I fly to.   You will have a head wind so that will shorten the distance.  

The centerline is the centerline so if you are on it, you won't have to worry about the sides of the runway.

This is 3800x60 with a gusty day.

I fubared the 1st approach.

The second one I was still scrubbing energy in the air above the runway, so landing almost midway down the runway, but since I scrubbed all the energy in the air, the rollout was very short.

Me, too. I was based my first 7 years at an obstructed 3000' field and also 3 years at a 3200' field. Now I have 5000' and usually make the midfield exit with only light braking.

[McMooney]

I've pretty much used takeoff flaps in the m20e since getting the IR 2 years ago,  plane lands rather short with brake usage being rare.

great visibility on the approach.  

funny thing, i actually stopped using flaps on the takeoff.

 

[PeteMc]

3 hours ago, RobertGary1 said:

I've noted that crosswinds in general often go away in the flare in Mooney's. I suspect its just because the wing is so close to the ground.

I would agree with a steady crosswind.  But when you're getting and then loosing strong gusts, I think all bets are off.  Suddenly loosing 6-10+ kts of wind when trying to get the wing to stop flying is always a potential issue.

 

[Hank]

4 minutes ago, McMooney said:

I've pretty much used takeoff flaps in the m20e since getting the IR 2 years ago,  plane lands rather short with brake usage being rare.

great visibility on the approach.  

funny thing, i actually stopped using flaps on the takeoff.

 

Me, too! Except I was doing it immediately, a couple years before starting IFR training. Works great! Less braking!

[GeeBee]

7 hours ago, RobertGary1 said:

In 20 years flying my Mooney through the winds in the southwest I’ve never lost aileron effectiveness in the flare. 

I did not say you would loose it, I said you had increased effectiveness. There is a difference.