How Much Wind is Too Much Wind?

For helicopters, that is.

Tomorrow, I’ve got a lengthy charter booked with a new client. It’s an animal survey mission, which will likely require me to fly low and slow over varied terrain. The job’s starting airport is at 5,600 feet, so the whole job will be at high density altitude. Fortunately, there’s just two of us on board, so power shouldn’t be much of an issue.

Unless the wind becomes one.

When I checked the weather on Saturday for Tuesday, it was forecasting winds 12 to 24 mph with gusts up to 37. I imagined myself battling a 13 mph gust spread with a tail wind when I was flying at 40 to 60 knots. It wasn’t a pretty picture.

I e-mailed the client and suggested that we move the flight up to today (Monday) or earlier on Tuesday, before the wind kicks up. I knew he was traveling, so I figured I’d follow it up with a phone call later in the day.

When I checked it again last night, the winds in that area had dropped considerably and forecasted gusts were only 25. That was more reasonable. I called the client and left him a voicemail message on his cell phone, explaining the situation and offering to change the date and time, but not making it seem so urgent.

This morning, the forecast is as follows for tomorrow in the flight area:

Sunny, with a high near 72. South southwest wind 7 to 10 mph increasing to between 15 and 18 mph. Winds could gust as high as 30 mph.

I sure wish the National Weather Service would make up its mind.

So the question is, how much wind is too much wind to fly?

My Experience with Wind

Although I liked (and still like) my primary flight instructor very much, there were two things he “babied” me on in initial training:

  • Radio work. I was crappy on the radio — which is odd, considering how well I can let my mouth run when around family and friends — and he made it a non-issue by handling many of my radio calls for me. I developed an early attitude of avoiding radio communication with ATC by actually altering routes to avoid airspace. I’ve since gotten over this problem and will talk to anyone on the radio.
  • Flying in wind. If wind speeds got over 8 or 10 mph, he’d cancel our lesson. I don’t think it was because he was afraid of the wind — he had over 1,000 hours of flight time. I think it was because he was afraid of letting me try to fly in the wind. Maybe he was worried I’d have a lot of problems. It didn’t matter. He made me afraid of the wind, which is ridiculous when you consider I’m flying a helicopter and can take off or land into the wind anywhere.

As a result of my initial training, I always faced windy flying days with caution. Maybe too much caution.

I remember flying my R22 from Wickenburg, AZ to Placerville, CA years ago. I was supposed to do it in one day. I got an early enough start. But I hit windy conditions at the Tehatchapi Mountain pass where I’d planned to cross from the high desert near Edwards Air Force Base to California’s Central Valley. Anyone who knows the area shouldn’t be surprised. It’s lined with dozens, if not hundreds, of windmills for a reason. But I was afraid to brave the pass and wound up spending the night at Rosamond, CA. I don’t recommend doing that and I certainly won’t do it again.

Could I have made the trip safely? Nowadays, I think I could. But then, I wasn’t sure.

I built all my flying time in my own aircraft on personal and commercial flights. When I got to 1,000 hours, I applied for a job at the Grand Canyon. I had a friend who recommended me to one of the tour operators there. I had a good interview and got the offer. Flying at the canyon had always been a dream of mine, so I happily took the job.

One thing about Arizona in the spring is that it’s windy. One thing about northern Arizona in the spring is that it’s very windy. I soon learned not only how windy it could get at the Grand Canyon, but how much wind we were expected to fly in.

Our company had two methods for determining whether it was too windy to fly:

  • We’d fly until one of the pilots came back and said it was too windy. Now most of the pilots were guys and most of them were in the 24 to 30 year old range. They spent their pilot lounge waiting time watching car races and extreme skateboarding shows on the television there. There was a definite testosterone thing going on. Obviously, if you came back from a flight and said it was too windy to fly, you were a sissy. So none of the young guys did it. There were also two women on staff, including me. Neither of us would call it because then we’d be confirming that we were sissies, which the guys already suspected. (Frankly, my personal gauge of what was too much wind was way off and I couldn’t trust my judgement anyway. I figured if it wasn’t too windy for everyone else, it couldn’t be too windy for me.) Fortunately, there was an older pilot named Ron who didn’t care about macho bullshit. When Ron went out on a flight and got tossed around too much in the sky — usually by the Dragon’s Tail or Dragon’s Head (two calling points on the Dragon Corridor) — he’d come back in a huff, go straight to the lead pilot, and shut us down for weather. The rest of us would breathe a silent sigh of relief.
  • When the wind in the company’s tower at the Grand Canyon Airport hit 50 miles per hour, we’d shut down. And yes, if Ron wasn’t around, we’d sometimes fly right up until that point.

So, as you can imagine, I quickly learned how to fly in high winds.

LTEThe only time I got into any real trouble was one day when I was landing on a pad in front of our terminal at the Grand Canyon. There was a good, stiff crosswind coming from my left as I hover-taxied into position. I was flying a Bell 206L1 C30P Long Ranger. Anyone with any experience in Bell products should be able to imagine what a 1000-hour pilot brought up in Robinson equipment might experience in such a situation: LTE (loss of tail rotor effectiveness). I started rotating to the right. I added left pedal and nothing happened. I added more left pedal and got a tiny bit of response. I was now almost 30° off center and my tail would soon be approaching the fuel pit. I slammed the left pedal to the floor, spun the nose of the helicopter around to face the front of the pad, and brought the collective down swiftly, for a rough yet straight landing. It was my first LTE experience and it scared the hell out of me. Robinson puts a hell of a lot more authority in its tail rotors than Bell does.

As another flight instructor once told me, “The wind is your friend.” He was right — but I couldn’t understand why until I’d flown in windy conditions. That taught me how the wind could help me take off and land with a heavy load or get to my destination faster. And how it forced me to dance on the pedals for a crosswind landing, or milk the collective to avoid the [over-]sensitive low rotor RPM horn on takeoff or landing.

The Risks of Wind

LTE is only one risk of flying in windy conditions. As I fly tomorrow, any time I’m in a crosswind situation, I need to worry about the aircraft trying to weathervane into the wind. If the wind is from the left, LTE becomes an possible issue — although I’ve never had an LTE problem in a Robinson. We’ll be flying light with just two on board, so I should have enough power to handle the situation. The trick will be to either avoid it (which I prefer) or recognize the onset and avoid it before it causes a problem.

Another risk of high wind to semi-rigid rotor systems (which is what most two-bladed systems are) is excessive flapping. This was our main concern flying Long Rangers at the Grand Canyon in high wind. (And you thought it was pilot air sickness.) When Ron came back and shut down flying for the day, he’d come into the pilot room and tell us all how crazy we were for flying. It was dangerous, he’d say. But what did we know? We were 1000-hour pilots, many of whom had no real life flying experience. How many of the former flight instructors around me did what my first CFI did and keep their students — and themselves — out of the wind?

My main concerns tomorrow will be keeping the aircraft under perfect control as I fly a search pattern. There will be a lot of turning back and forth and maybe even a little hovering. I’ll have to keep track of where the wind’s coming from and what low-level obstacles — think hills and ridges — it has to cross to get to me. Each little bump in the ground means a bump in the air on a windy day.

How much wind is too much?

I know a lot of pilots who won’t fly in what I now consider moderate winds (10 to 25 mph). This past February, I was in Parker, AZ, doing a video flight for an off-road race. There were a bunch of helicopters working for various race teams or video production crews. Before dawn, as the cars were lining up at the starting line, they took off, one by one. The winds were 13 gusting to 18. I was prepping my passengers for the flight when the pilot of a Jet Ranger came over and asked if I was going to fly. I told him I was and I think he was surprised. He told me it was too windy for him.

Anyone with significant flight time who reads this should be able to give me an idea of their own personal maximums for wind. I’d love to get your feedback here. Use the comments link or form. And if I’ve said anything absolutely stupid in this post, please correct me gently.

At this point, I’m thinking that 30 mph with a gust spread of no more than 10 mph should be okay for this mission. If I find out I’m wrong, I’ll be sure to let you know.

In the meantime, I’m hoping my client calls to start the mission an hour or two earlier. I think if we can finish up before noon, we’ll avoid the worst of the wind.

15 thoughts on “How Much Wind is Too Much Wind?

  1. For me, an airplane flier, I’ll cancel a flight if the gust factor is over 10 kts or the crosswind is pushing to within a few kts of the demonstrated crosswind component for the airplane.

    I also tend to avoid steady winds over 25 kts, even when there is little gust factor, since it gets pretty bumpy pretty quick. If I’m taking up a non-pilot (sight-seeing for fun) then I usually halve my normal limits.

    Jason Miller´s last blog post: Looking straight down from 2000 feet

  2. I am much lower hour’d than you Maria at circa 150. Your comments on being “mothered” by FIs while learning rings a bell. Luckily my radio work is good; but I think over here they are way to cautious of wind too.

    I personally won’t lift if the wind is forecast > 20kts; with a max 10kt spread; and never gusting >25kts. Luckily, our Met office are normally fairly accurate!

    Really good article!

    Craig Parsons´s last blog post: Robbie is Rotor & Wing Hot Item!

  3. I am also not a very high hour pilot, but i get free flight time from my school by helping in frost control missions. When we travel to the airport we will be working from, we have to go if we want flight time, so we basically don’t have a choice. Before I started doing this, I was uncomfortable flying above 12 kts. After a couple flights in 25-30 kts, gusting over 40, I got over it.

    I’m still iffy about flying in conditions over 15 kts, but only because of taxiing and getting myself into LTE, not anything once i’m up in the air.

    The only times I’ve gotten myself into LTE have been in a hover, and the robinson let me recover nicely. I have yet to experience severe lte while I had a decent airspeed. You shouldn’t have a problem with that forecast.

    • The flight actually went very well. The winds were pretty calm for most of the survey area. There was a rocky bluff and a handful of buttes, however, where the wind did some weird things on the lee side. Had trouble doing the slow flight without pointing into the wind there. One or two minor cases of LTE that the R44 got through without too much trouble. What’s sometimes scary about LTE is that one way to get out of it is to push the cyclic forward and get some airspeed, but when you’re flying 50-100 feet off the deck, the resulting dip in altitude can be a bit unnerving. And if you’re heavy and already pulling about as much pitch as you can, there’s not much you can do to avoid the dip.

      But it worked out okay.

      I’ve done some ag work — drying cherries — but so far have been fortunate enough not to have to fly those missions in high winds. After all, if the wind is stiff enough, the trees don’t need a hovering helicopter to shake the water off — the wind will do it.

  4. I’m just getting my commercial license now few weeks left actually, and I’m going to go rock some full down autos in 18 knot winds gusting 25. wooop

    • Zack: It’s the gust spread that’ll get you. Imagine this: the wind is 15G25. So one minute, you have 15 MPH and the next you have 25. How do you think that’ll affect lift when flying into the wind? Or away from it?

      Not a biggie when you’re cruising, but it could affect you near the ground. Keep it in mind.

      Have fun and fly safe!

  5. Probably a stale thread here but I thought I’d throw in my $.02 since this is a topic I often look online for stories on. I’m a 600 hour pilot from Canada and used to be terrified of winds. Turbulence to be more specific. I’ve read a few TSB reports on mast bumping because of a low g situation caused by turbulence. The idea still is unsettling to me today when I’m flying along in turbulent conditions. Unfortunately I fly for corporate so I often have to fly unless it’s a safety issue whereas my colleagues who are tour pilots can shut down earlier due to passenger discomfort.

    When I started this job I used to not go out over 12 knots or so, but then I did a ferry flight from Boeing field to Osoyoos. I saw winds gusting upwards of 40 that day, combined with the hills of Chelan, the August heat and an R44 with a very light load, let me tell you, it was a terrifying ordeal! I do believe it toughened me up though. My tolerance went way up after that, I guess in the back of my mind I figured “If a 44 can survive that ride, it surely can handle this puny 20 kt wind!”

    I do still worry about a good downdraft unloading the rotor, but as time goes on I’m learning how to best avoid the really bad stuff (stay out of mech turbulence areas, etc).

    CJ

    • No such thing as a stale thread here — especially in the helicopter posts!

      It’s always good to gently push your comfort level when flying, especially as you begin your career and start to build hours where you’re responsible for safety. The more wind you fly in, the more comfortable you’ll get with it. Ditto for turbulence. I think gust spreads are a bigger concern than sustained winds; I’m more likely to cancel a flight with wind 15 gusting to 40 than wind 25 gusting to 30. It also has a lot to do with terrain — flight over flat land isn’t nearly as big a problem as flight in the mountains. Do keep in mind that some helicopter rotor systems handle wind better than others; a fully articulated system can take a lot more abuse than what you’ll find on a Robinson or Bell 206.

      Thanks for taking the time to comment!

    • I fully agree on the articulated rotor system. So the question remains though: “How much wind is too much for the R44 where you become unsafe?”

      The only answers I’ve been able to find from the net are on passenger discomfort, not the integrity of the ship itself.

      I still remember my conversation with my mechanic when I got back from that trip: “You need to come down here and fix the 44, I broke it” Mech: “What’s wrong with it?” Me: “I’m not sure exactly, but there’s no way it went through all that without breaking anything, something HAS to be broken!”

      P.S. I love your site and your writing. It’s one of my favorite blogs to visit :)

    • I don’t think there is an official answer. I know I’ve been through some pretty rough turbulence in my R44 (and even in an R22) and nothing broke. This would probably be a great question for the folks at the Factory Safety Course.

      Related story: The third time I took the Robinson Safety Course, I had at least 2000 hours under my belt and did the flight in an R44. I asked the CFI I was flying with what the maximum bank angle was. He replied, “You can bank at least 90°,” and then did so during the flight. I never want to do THAT again.

    • I’ve had the Robbie course guy show me some serious bank angles! And as long as the rotor stays loaded and Gs positive.. there’s no danger at all.. even though you’re basically upside down! Haha I regularly make sharp banking turns to keep times down on tours. And not HotDogging.. but it simply gets you up to and back down from altitude

    • The safety course guy I last flew with demonstrated a 90° bank turn when I asked him how steep a bank the ship would do. I would NOT do that with passengers on board unless I had a serious need to avoid something. I don’t do any aggressive maneuvers on tours. I don’t want to scare passengers or make them sick.

  6. Hi Maria! Great write up! As usual!
    I’m a 1000 hr pilot myself, and fly tours off the end of a small pier the juts out about 400 feet over the ocean. Winds forecast to be 15-20kts are regularly 25-40kts out over the ocean.. and worse when we’d fly the tours near the line of tall resorts and buildings lining the coast.. they acted as wind tunnels!
    I used to only fly up to about 15-20kts steady.. and my max gusts.. maybe 8-105kts spread.. until I started working at this company.. I’ve been asked and expected to fly in greater winds.. even while storms were rolling in…and I got used to it and I thought, pretty good at it as yes, wind is your friend in certain situations.. however.. I started taking into mind how uncomfortable the tourists were… and thas what I’d gage my limits on for that particular job.. (as well as abuse of the aircraft if it got that strong)
    now back flight instructing and doing tours with then school. . I have a better understanding of what we should and should not attempt.. i.e. Today, I just canceled 3 demos and tours in the R44 for winds 25mph gusting 36.. and getting worse by the hour.. forecasting 29 gusting 45.. pretty hairy. But better to be safe.
    Keep writing! I enjoy your blog!

    • On tours, it’s all about passenger comfort. I really don’t like giving passengers a bad experience. Otherwise, it’s all about mission safety. The raptor surveys I used to do in Arizona required 20-30 knot speed with three people on board. Add high density altitude and a stiff wind that could be at your back and you’re operating at max performance just to stay airborne. Very challenging work, especially when the wind whipped around those cliff faces.

What do you think?