Sunday, May 15, 2011

Weather and Retrieve for Cross Country Flight

Weather and Retrieve for Cross Country Flight

Recently a group of pilots got together to discuss flying, particularly cross country (XC) flying.  The first long flying days of the season are starting and everyone is itching to go far.  XC flights are some of the most rewarding and challenging in the world of flying.  Going XC can also be dangerous, and the risks should not be taken lightly.  With XC, the pilot is always flying into the unknown.  After leaving a comfortable home flying site, whether we choose to make the crossing, go deep, or simply glide out, we always arrive someplace new. 

Over the flats.  Photo by Chris Amonson


Before heading out for that next big XC, it’s good to think about lessons from earlier flights and procedures that go with flying distance and getting home again.

Conrad Kreick provided a window into his weather analysis methods for deciding where to fly.  His expertise and experience in choosing great weather has paid back in great flights this spring.

Meredyth Malocsay was able to summarize the conversations about how to make retrieves more efficient and organized. Her summary is in the form of a list of equipment--from required items to ones that are handy to have.  She also distilled the lengthy conversation and experiences into “Rules of Thumb” that provide a general guideline of priorities.

WEATHER BASICS

In the Northwest, we have access to three excellent forecast models. They are the Global Forecast System (GFS), the North American Model (NAM), and the Rapid Update Cycle (RUC). When trying to decide if a site will be flyable it is best to look at as many different models as possible. If they all indicate good flying weather, you can have a high level of confidence that you will be getting a good flight. On the other hand, if each model tells you something different, then your confidence in your forecast will be low.

I have seen days where one model forecasts a great day of flying while another showed the opposite, and the true weather matched one of those models. If you had only looked at one model that day you may have used up a day parawaiting or perhaps missed a good fly day mowing the lawn.

When there is disagreement in the models, the true forecast is often somewhere in the middle. If the one model shows winds that are just within your safe launch standards while another shows much stronger winds, then it’s probably not worth a drive across the state because the odds are launch will be blown out. If you’re looking for an excuse to spend some time outside though, it might be worth heading to launch just to see which model is closer to the truth.

To improve the accuracy of your forecast it helps to monitor the weather and the forecasts each day. The model that most accurately predicted today’s weather will usually be closer to predicting tomorrow’s weather. When the trend has been very accurate and the models all agree, then you can be very confident in the forecast. And if that forecast shows a record setting XC day, skip work, call your friends, and go fly.

Here are some questions I ask when looking at the weather forecasts:

1.      Will it be overcast? Some clouds are good. Too much and the sun’s energy isn’t able to warm the ground enough to produce good thermals.
2.      Will it rain? If there is a good chance of rain during the day I usually stop right here and decide what else to do for the day.
3.      Will there be lift? Am I up for a good hike and a sled ride or do I only want to commit a day to flying if I can stay up for an hour or more.
4.      Will I be able to launch? No point in going to launch if the wind will be too strong or over the back.
5.      What will the air be like once I’ve committed to aviation? Site-specific knowledge is helpful.
6.      If I’ve gotten this far, then I start looking at what I can make of the day. How high can I get? How far can I go? Will the chance for a good flight be worth the drive?
7.      And the most important question of all: Will I have fun?

Answers to all these questions can be found on XCSkies.com. If you don’t want to spend the $35 annual fee for XCSkies you can find the same information at the University of Washington, Department of Atmospheric Sciences web site (http://www.atmos.washington.edu/mm5rt/). Another source maintained by T. J. Olney can be found here:  http://home.comcast.net/~wxtofly/
  
For more advanced information I look at the pressure gradient for the day. Are the isobars close together indicating stronger winds or perhaps there is high-pressure overhead leading to stability? I might also look at surface temperature relative to air temperature to assess stability and I look to see how cold it will be at the top of lift. Will I need my warm gloves? Cold air is denser too, so lighter thermals on a cold spring day can give us a good flight while light thermals in August might not keep us off the ground. I also monitor any fronts moving through the area. Pre- and post-frontal conditions can produce some exciting flying. And it pays to watch the jet stream. It can affect the way the weather develops over the next few days. It can also change the air we fly, especially around some of our higher launches.

To summarize: I first look to see if the air will be flyable and whether I’ll be able to launch, or if I’d want to launch. Then I look to see if it would be fun to fly and what I could make of the day. It is important to check as many models as possible and to develop a pattern showing which models are the most reliable. When the trend is favorable and the models agree you can be very confident in your forecast.

The long empty road back. Photo by Chris Amonson


FOR A SMOOTH RETRIEVE
Be prepared
  1. Know you wing.  Fly equipment that is suitable for your skill or comfort level.
  2. Know how to use your vario, radio, GPS, and or Spot device.

"Required" Equipment
  1. Working radio able to receive and transmit on the USHPA frequencies.
  2. Mobile phone
  3. GPS

"Good to Have" equipment
  1. Spot device
  2. Big thick lawn/leaf garbage bag in your pack for shade or rain.
  3. Water and food.
  4. A sign for hitching reading “Pilot needs ride” or something similar.
  5. Something to read.

"Really nice to have" (in retrieve vehicles)
  1. Nuvi or something capable of “goto” coordinates.
  2. 50 watt radio able to receive and transmit on USHPA frequencies.
  3. Cooler with drinks.
  4. Charger for phones and electronics.
  5. Straps of some sort in your car for bags on top.

(Every situation is different - so it is always dependent on the day, trucks, area, who you rode with, etc. That said, here are some general rules of thumb that seem to make sense based on our experience so far).
  1. Leave keys on rig and make sure group knows where (hitch, strut, gas cap, license plate).
  2. At Baldy, designate one person to leave their gate key under rock by locked gate on the way up (have your name on it).
  3. Coordinate frequency and radio check on launch.
  4. Make sure you have contact numbers on launch.
  5. Have your GPS (and Nuvi or car GPS) in dd.dddd format.
  6. Have a user field or way to look at "distance from takeoff" on your GPS for radio call including position.
  7. Periodically call out on radio = who, altitude, location, intention (ex: Arun, 9200, Bridgeport, heading north).
  8. Bring the trucks down from launch before retrieving bodies, if possible.
  9. Gather short dirters first and regroup to plan long haul (Baldy-truckstop, Saddle-Mattawa grocery store, Chelan-lz or subway).
  10. Wait for long guy to land to see what makes sense for retrieve, or send the guy/car that makes sense for really long haul, in case it turns into that.
  11. If you don’t have an smartphone, learn how to use twitter for spot texts.
  12. If you have a smartphone, load app to make spot locating easy (iPhone-Shared Pages, Windows-Spot Locator by Iain Frew, droid-Shared Pages)
  13. If you have a Spot device, have your shared page clear every 24 hours. Email your Spot url to Dave Wheeler, and have twitter account receiving ok messages.
  14. Land, send Spot "OK" message, then start packing up with Spot out and exposed to sky.
  15. Leave your radio on after landing, and make sure your cell phone is on and where you can hear it.
  16. Have your Spot message go to your own phone also, so you can tell it was sent successfully, and for handy cut/paste to others.
  17. Try to make your own way back first. Don’t assume you'll get picked up.
  18. When you start hitching/walking to make your own way back, start Spot tracking again
  19. If you get a ride, text that you did.
  20. Give and accept gas money for retrieve and launch rides. A trade system too hard to keep track of.
  21. If you've been retrieved or plan to be, expect to be doing some retrieving as well.

Courtesy to Retrieve Drivers

Think about how you would behave if a perfect stranger stopped to give you a ride. Then treat your friends the same way. Have a good attitude and be thankful that someone came to get you. Having happy pilots in the car makes retrieve go faster!

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