I’ve Seen the Effects of the Wind

It’s invisible. The only way to know it’s there is by seeing, feeling, or hearing its effects. But the wind makes a big difference in the performance of a flight, particularly a longer flight.

It’s easy to think of wind in terms of the surface winds we feel outside. A light breeze might clock 5-10 mph, a good wind for flying kites might reach 15-20 mph, and anything 30 mph or more might blow your chihuahua away. Hidden from most people’s awareness are the winds far above the surface when jets fly – 20,000 feet up to maybe 45,000 feet. The winds aloft, as we call them, are often much stronger, ranging from 40-50 mph up to 120 mph or even higher. While they don’t stop an airline from flying, they can greatly affect flight times and fuel burn.

How the Wind Affects a Passenger

When you book a flight, you see a time for departure and arrival. It’s tempting, and somewhat reasonable, to view those times as a promise. However, it’s rare for a flight to depart and arrive exactly as scheduled. Obviously, some flights depart late for any number of reasons, but even an on-time departure might arrive at its destination early, right on schedule, or late. The winds aloft, especially on a flight over two hours long, are one of the main reasons.

When an airline publishes a schedule months in advance, the planners have no idea what the weather or winds will be doing on the day your flight departs. So they make an educated guess based on the typical times for similar flights in the past and the general pattern of the winds along that route. The average winds aloft are stronger during the winter and weaker during the summer. Also, the winds in the continental U.S. generally blow from west to east. So the schedule planners might plan your Vegas to Baltimore flight to take 4 hours 25 minutes in January when the tailwind is likely to be stronger versus 4 hours 40 minutes in July when the winds are weaker.

But remember – it’s only an estimate. What actually matters are the winds aloft on the day you fly, and they can vary quite a bit even from one day to the next.

Here’s one example. This map shows yesterday’s weather and jetstream, the areas where the winds aloft are strongest. The dark blue lines with arrows indicate the jetstream. The winds are fairly consistent and strong from west to east until they reach the eastern states, when the turn southeast.

Thanks to the strong jetstream over the western and central US, one Vegas-Baltimore flight scheduled for 4h 25m only took 4h 12m, or 13 minutes less. Nice!

Here’s another map from today. Down south the winds are about the same, but the jetstream bends strangely from north to south over the Rockies.

What does this mean to our Vegas-Baltimore flight? Instead of getting a boost from a strong tailwind most of the way like yesterday, it gets a bit more of a crosswind over the middle of the country, meaning the plane can cover a bit less ground in a given amount of time with the same amount of effort. If you average out all the winds for the whole flight, today’s has about 22 mph less tailwind than yesterday’s. That makes today’s flight reach Baltimore about 8 minutes later than yesterday’s…still early by a few minutes, but not as early.

How I Can Help

When you drive somewhere, say from Dallas to Fort Worth, you have some options regarding your route. Maybe you like I-30, maybe you like I-20, or perhaps you prefer side streets. For an airline, routing works the same way to some degree, but not entirely. For most of our airports and flights, we have some flexibility regarding the path we take. However, to help air traffic controllers manage all the flights in the air, they generally prefer that we use certain routes that work well for them. We store those routes in our flight planning software and use them by default unless there’s some good reason not to.

Here’s where I come in.

On long flights such as Vegas-Baltimore or Orlando-Denver, I often run multiple versions of the flight plan. The first uses the preferred route. The second lets our flight planning software magically determine the ideal route using the current winds. Often, the preferred route is already ideal. But when the winds vary significantly in direction or speed from one part of the country to another, sometimes the ideal route (“best winds route,” in our jargon) is hundreds of miles north or south of the preferred route. If the custom route saves time and fuel over the preferred route, I can file it with air traffic control. As long as it doesn’t cause problems for their traffic flow, they usually let my flight use the route.

Here’s one example for an Atlanta-Vegas flight. The preferred route is white, the best winds route orange. Note how the best winds route stays north of the pref route to stay away from the jetstream. Sometimes the best winds route is longer than the pref route, but because its winds are better, the enroute time and fuel burn are lower.

Best winds routes take extra work and are not required. But unless I’m really busy and don’t have time, I give them a try on my long-haul desks. Why bother? They can save a lot of money.

Suppose I tweak the route on my Vegas-Baltimore flight to catch more of a tailwind. It might save 500 pounds of fuel and 6 minutes of flying time. That might not sound like much for a flight that’s burning 18,500 pounds of fuel. However, with jet fuel in Vegas costing $3.40/gallon, those 500 pounds translate into $253.73 in savings. In terms of net profit for the company, it’s like I convinced one more passenger to buy an advanced-purchase ticket. And it took maybe 3-4 minutes of extra work. No brainer, right? These make me seriously happy.

Sometimes I only save a couple hundred pounds, maybe $100 worth of fuel. In certain circumstances, I’ve saved $600-700 or more on a single flight. If I can plan several best winds routes in a shift, I can pay my salary for few days just in fuel savings. Those are some of the times I know I’m really making a difference at work.

The next time you fly somewhere, I suggest thinking about three things:

  1. Compare your actual departure and arrival times to the scheduled departure and arrival times. How much do they differ? Any ideas why?
  2. Even though it’s really hard to see their effect, look outside and think about how strong the winds are.
  3. Raise your glass to the flight dispatcher sitting in a room back at airline headquarters who planned your route and fuel load and is monitoring your flight.

Disclaimer: All thoughts expressed here are solely my own and do not necessarily represent those of Southwest Airlines, its Employees, or its Board of Directors.

Mars or Bust

On Wednesday, a group called Inspiration Mars announced plans to send two people to fly by Mars and return to earth in 2018-2019. This public-private partnership would send humans exponentially farther from home than we have ever been. One leader called it “a philanthropic effort to be done for America” rather than for profit.

I love this plan. NASA doesn’t have the cash to attempt something like this, so the private sector is stepping in with a bold plan. It’s old-school science with a sense of adventure and risk-tasking where people try something partly to prove it can be done. Despite the technical challenges, the plan seems to be feasible and relatively low-cost. The spacecraft should reach Mars during a relatively close approach to earth, do a simpler fly-by of the planet instead of a much riskier and more complex landing, and inspire millions of people who are disappointed by the end of the space shuttle program. Much of the necessary technology already exists. The rest can be developed over the next few years.

Are Jenny and I applying for the trip? As tempting as it sounds, no, for three reasons:

  1. Let’s be honest: there’s a decent chance these two might not make it home. As this article noted, if the trajectory is off, the spacecraft could slam into Mars, careen off toward the outer planets by mistake, or re-enter earth’s atmosphere too steeply and burn up. We’re talking 30 million miles away. If we didn’t have kids, I’d be much more likely to consider it. But I can’t risk orphaning the boys for the sake of something like this.
  2. I couldn’t stand to be away from the boys for over 16 months. For comparison, Jonathan was born 37 months ago. So much can happen in that amount of time. When we got home, they’d be such different little people.
  3. We probably aren’t what they’re looking for, anyway…too young (apparently they want older people due to the radiation risk), not the right skillset (space background with mechanical skills), etc. But I must admit that blogging from space would be pretty darn cool.

So I’m afraid we’ll cheer from the ground instead. (You’re welcome, Mom!) However, I’m still curious about many of the details particularly the experience for the astronauts. Several questions come to mind, such as:

  • How will they pass the time without going crazy? I assume printed materials are out of the question due to weight and room. Are iPads or Kindles acceptable? Will the spacecraft have a built-in entertainment system of some sort?
  • How well will communication work between the crew and Mission Control? How long is the delay? Is video communication possible or only audio? How much monitoring will Mission Control be capable of?
  • On a related note, how much privacy will the crew have? Assuming the crew is a married couple, will they be able to have a semi-normal sex life or private conversations without Big Brother intruding?
  • How much training will they get, and what will their capabilities be, regarding repairs, medical care, spacecraft maneuvering, mental health, and other issues they might encounter?
  • What kind of exercise capability will they have to keep their muscles and bones strong?
  • What will they eat?

If their plan comes together, I hope to share it with the boys. I just told Brenden a story about a boy named Brenden (of course!) who got into a spaceship and flew to Mars. Turns out that story might not be quite so crazy after all.

Blog Soup 1/26/2013

Welcome to the first Blog Soup of the new year!

  • I’m on shift 12 of 14 in a row at work. Don’t feel too bad for me, though. I did it to myself. We normally work six shifts in a row followed by a three-day or six-day break. I picked up a trade and a couple of overtime days last weekend, which is why I’m on such a long stretch. It also includes five shifts training a new guy. I am looking forward to some time off next week.
  • Next Thursday I’ll hit my nine-year anniversary in Dispatch. Before I know it, I’ll be having a retirement party and taking my grandchildren to Disney World.
  • I’ve been working on our spring season race calendar. Right now I only have two big events planned, but I might add some smaller events in between. First up is a return to the Cowtown half marathon on Feb 24. As you might recall, Cowtown was my first half marathon last February. I barely missed my goal of finishing under two hours. After a more leisurely and fun half at Disney World earlier this month, I am training hard to break 2:00 next month. I know my body is capable of it. The only question is whether everything will come together to make it happen that day.
  • Our other event is a 100K bike rally near our first house, the Cross Timbers Classic Bike Rally. It starts with a lap on the track at Texas Motor Speedway in north Fort Worth and does a loop through the surrounding area. Jenny and I both signed up for the 100K ride (62 miles). So far our longest ride was 50 miles at Hotter’N Hell back in August, so this one will be a new challenge.
  • I used some Amazon gift cards to get a cool new toy, an iHome rechargeable speaker dock for my iPhone. Why is that cool, you ask? It lets me carry the speaker to any room in the house and listen to my music or Pandora. I’ll mainly use it for listening during a soak in the bathtub (no outlets in the bathtub room) or in the kitchen while hanging out with the kids. It’s maybe a foot wide and has a built-in dock for my iPhone or iPad. For such a small unit, the sound is surprisingly good.
  • Aussie tennis star Samantha Stosur has better arms than I do.
  • I was thrilled by the deep run that young American Sloane Stephens enjoyed at this year’s Australian Open, especially her huge win over Serena Williams. Stephens is developing into a phenomenal player and also seems like a very warm and good-natured person. If she can stay healthy and handle all the pressure, she seems poised to take over as queen of American women’s tennis.
  • I don’t really understand the drama over gun control. The pro-gun people are all worked up because they think the government is trying to take all their guns, which is untrue. The anti-gun people think that tighter gun control laws will keep us safe, which is also untrue. Based on what little I’ve read, the measures being proposed would not have stopped most of the mass shootings from the last 10-20 years. Even if these new measures pass, I doubt they will have much impact. The only way to completely eliminate gun violence in America is to wave a magic wand and make all guns worldwide disappear. Even I don’t think that’s a good idea, even if it were possible.
  • An acquaintance of mine decided to take out $50,000 in student loans to get a master’s in film from a private school in California. Now she can’t find a job but owes nearly $700/month in student loan payments. She set up a crowdfunding site to raise money to pay her loan. Part of me wants to help, but the other part thinks she was unwise to borrow that kind of money to pursue a degree with such questionable marketability. Just thinking that makes me feel old.
  • Screw my man card. I wish I had Lady Gaga tickets for Tuesday.
  • Jonathan had his three-year-old checkup this week. He was very healthy as expected. He measured 90th percentile for both weight (37 lbs) and height (39.5 inches). His language and motor skills are normal. We’re working hard on potty training this weekend. It still amazes me to watch these two grow up.

Two Views of Weather

In everyday life, weather determines how comfortable you feel outside and what outdoor activities you might choose. It guides choices like what clothes to wear, whether to wash your car or run the sprinkler system, and whether to take the kids to the park or keep them home with a craft or movie. We get the weather report on TV or the radio to plan our days and weekend activities. Unless an unusual weather event is occurring, such as a hurricane threatening Florida or a crippling blizzard in Denver that makes national news, we don’t really care much about what the weather is doing outside our vicinity.

Flight dispatchers look at weather in a different way from the majority of people. We work in a climate-controlled office while analyzing weather we’ll never see in areas hundreds or even thousands of miles away. We don’t care how the weather makes anyone feel, and it doesn’t really affect our own activities within the office. However, it makes a huge difference in how we plan our flights, but maybe not quite in the way you’d expect.

Good and Bad Weather

Regular people and dispatchers have different definitions of good and bad weather. What’s good for one might not be good for the other.

For Joe Blow:

  • Good weather probably involves a pleasant temperature and a lack of precipitation so he can feel comfortable outside.
  • Bad weather keeps Joe inside and might involve extreme temperatures, high winds, or precipitation.

For a flight dispatcher:

  • Good weather is any weather that allows us to operate a flight as intended – safely, legally, and on time.
  • Bad weather is any weather that might prevent us from operating a flight as intended, such as thick fog, low clouds, thunderstorms, or freezing rain that ices up runways and aircraft. It also forces us to carry lots of extra fuel for holding and possible diversions, forces us to divert at times, and/or prevents us from departing at all.
  • Weather that is unpleasant to people such as rain, hot or cold temperatures, or strong winds don’t necessarily prevent a flight from operating safely. As one of my trainers said once, our planes work fine in the rain.

So we can sum up the two views of weather as such:

  • Normal View: Do I want to be outside?
  • Aviator View: Can my flight reach its destination as planned?

The Rules

The FAA and airline policy forces us, generally with good reason, to follow a cornucopia of rules when we carry paying passengers on a flight. One rule says that we cannot land a plane if the visibility or lowest cloud layer (ceiling) is beyond a specified threshold for the runway we want to use. These values are known as minimums (or minima, if you want to use proper Latin…and I KNOW you do). Normal people don’t usually care about ceilings and visibility because it doesn’t affect them. A 100 foot ceiling might be perfect for a cool walk in the park but a showstopper for a pilot trying to land at an airport.

One common limitation for a good runway is visibility of 1/2 mile and a ceiling of 200 feet. If the visibility is at least 1/2 mile, the crew can line up and descend toward the runway to land. If it’s lower than 1/2 mile, the crew must hold until it improves or divert. Once the crew descends toward the runway to land, the pilots must see the runway at least 200 feet above the ground as they descend. If they do, they can land. If not, they must climb out, go around, and try again or divert.

Buffer Zone

Predicting the future in any field is a mix of art and science, and no one bats 1.000 in any field of prediction. The Feds and every aviator in the world know this. So the Feds added another rule to offset the inherent limitations in a forecast: the alternate rule. It specifies a buffer above the typical minimums and requires us to designate an alternate airport if the forecast weather is anywhere within that buffer zone or below. For most operators, the threshold is 2000 foot ceiling (10 times the minimum ceiling for a good runway) and 3 miles visibility (6 times the minimum visibility). If the weather is below those limits, we must name an alternate airport and carry enough extra fuel to divert there if needed. That way if the weather gets worse than forecast and prevents the flight from landing, we have somewhere to go. We spend much of our brainpower evaluating forecasts, watching trends in visibility and ceiling along with precipitation, and deciding whether an alternate or extra fuel is required or simply a good idea. (I might explore this idea in more depth in a later post.)

So which view of weather is correct? Both, of course. Joe Blow doesn’t have to care that San Diego is fogged in and below mins because he can still run on the beach with his dog. Meanwhile, I don’t have to care that Betty Boop’s picnic in Houston got rained out because my HOU arrivals are plowing through the rain with no problem. Each view is valid for its own purposes.

Interconnected Smoke Detectors

Like most houses built in the 1980s or earlier, our house came with old-school smoke detectors and not many of them. Both were in the upper hallway outside the bedrooms on the second floor. We had none downstairs or in any of the bedrooms. I guess the builder figured the smoke would rise through the atrium and eventually trigger the alarm, presumably waking up someone in one of the bedrooms behind their closed door.

Yeah, that didn’t sound very comforting to me, either.

In the 1990s, the building code changed to require new homes to have interconnected smoke detectors. That way if one went off, it activated all the others to increase their chances of being heard. Our first home had this feature, and I loved it. However, I didn’t want to hire an electrician to rewire my current home. My solution?

Kidde Wirelessly Interconnectable Smoke Detectors

Designed specifically for situations like ours, these detectors can talk to each other wirelessly. I installed one in each bedroom and two downstairs. If one detects smoke, everyone in the house will know about it within a few seconds. The setup was very simple, and they work great. The price wasn’t too bad, either. If your home doesn’t have interconnected smoke detectors, I highly recommend giving these a try.