Sunday, December 08, 2013

Crosswind flying and landing.

Note: Actual or former pilots/flight crews might find this post a touch on the boring side.

So yesterday when I went out to fly, there was a pretty good crosswind, 10 knots out of 320 (coming from 320 degrees on the compass, or out of the northwest). The runway at the airport os an 08/26 runway, meaning that one end goes towards 080 on the compass radial (east) and the other end goes to 260 (west). Using Runway 26 and taking off/landing to the west gives me a 70-degree crosswind. It's manageable and within the capabilities of my aircraft, yet challenging enough to give me some decent practice.

Now normally when you're around an airport, you fly a traffic pattern that's supposed to ensure safety by putting everyone on the same sheet of music. Ideally, everyone flies the same direction at the same altitude and no sheet metal gets bent.

A simple pattern one looks (in theory) like this:

Now that's all well and fine when there's no wind, but add a crosswind and you start to find yourself blown in whatever direction that wind's going. And since your pattern will invaiably take you in a few different directions depending on which leg you're on, the wind effect will be different on each one. A runway crosswind will try to blow you out and away from the runway if you're downwind of the runway, and it'll collapse your pattern and push you in towards the runway if you're upwind. To counter this, you often have to turn your nose windward so that you're kind of flying sideways in proportion to that wind. We call this a "crab" and it looks something like this:
The real trick is remembering to kick that correction back out just before the aircraft touches down. You may have to fly in crooked, but you have to actually touch down straight lest your airplane gets stressed unacceptably (to say nothing of your passengers).

Now making it even more fun is that when you turn your base turn to approach the runway, that wind suddenly becomes either a headwind, slowing you way down, or a tailwind, speeding you up and pushing you past your final turn point unless you're on the ball and you sharpen your turn and cut it short. The on final, you go back to a crab again, or you put your downwind wing down and descend towards the runway with your plane cocked like this:
When you finally get around to your final approach though, most airports are nice enough to have some neat little red and white lights set up to tell you if you're too high, too low or just right. At my airport, these are VASI lights (Visual Approach Slope Indicator).
There's a catchy little ditty used when you look at these lights.
"Red over white, you're looking all right. Red over red, you're about to get dead."
Keep the lights in sight, and as long as you've got two red over two white, you're right in the correct glide slope for the runway. Keep the airspeed up and manage the wind and you can't miss. However, if you spend too much time watching the helicopter taking off from the parallel taxiway and departing to the east as you land to the west, those sneaky VASI lights have a way of turning all red. (NOT something you want to see on a short final.) That's when you kick yourself in ass for getting distracted then roll power on and climb to back up to the proper landing profile. Uh, so I hear, anyway.


  1. Nice precis... and red/red = you're dead

  2. Whaaatttt? Just put your velocity vector on the touchdown point and drive it on to the runway. After the wheels impact the runway, pull the power back if desired and deploy the drag chute. Well, that's how my USN instructor taught me how to land the F-4. Scared the livin' hell out of my USAF instructor on the next ride though!

  3. @ Juvat: LOL. I made my "short field landing" kind of like that during my first FAA check ride.

    It's never good when you impact the runway hard enough to knock your check pilot's headset off.

    When I re-tested a week later, it was much better and I actually got signed off.

    I'm still jealous over your F-4 flying, though.

  4. "Red over Red". Unless you're trying to set a Sabreliner down on a really really short tropical strip and then it's "Red over Red, hit the nail on the head".