Danger Danger

Modern airliners are equipped with a wide variety of warning systems. All of the ones I can think of at the moment were installed in response to a tragic event some time in the past.

windshear.JPG

The photo above was taken over the desert on approach to Phoenix. At the time there was no mention of adverse weather in the area. The small storm had pretty much rained itself out and was dissipating rapidly about ten miles from the airport. That’s not good.

Notice how the rain shaft on the left hits the ground then rolls up in a rotating tube. That’s not good either.

We were still several minutes from landing and included a “Windshear Escape” review in our approach briefing. This means that based generally on what we could see out the window, the spread between the temperature and dew point, the way the rain was curling up against the desert floor, and our landing weight it was a good idea to be prepared.

Our aircraft based equipment for windshear prediction is excellent and the ground based Doppler system from the control tower is pretty good but there is no replacement for looking out the window and understanding what you see.

The dissipating storm tearing up the desert was still a few miles from the airport, only minor airspeed fluctuation from windshear should be expected. But if much more was encountered we would execute the escape maneuver and bolt for an alternate airport with minimum fuel.

All of this sounds like a lead up for a great windshear story, but it isn’t.

What I should have been concerned about was the Sun. By the time we were landing the sun was setting and was shining through a curtain of rain. We had to stare through this during the approach and landing.

The runway was visible but the glare level was immense. The runway with no electronic guidance was still a good choice, it was longer, farther from the rain shower, and closer to our gate than the others.

I set up a calculated glide path for reference and relied on the runway VASI lights for primary guidance. The First Officer did a fine job of flying the approach and only forgot a few of his altitude callouts and flopped the landing. By the time we turned off the runway we were both practically blind from staring into the combination of rain, sun and sun reflected off of the ground and more rain. This was one of the most unusual visual combinations I have seen.

Maybe next time I will remember to include the Sun Angle as a briefing item, especially with rain in the area. It seems that it’s always something in addition to what you expect that should be expected.

Advertisements

2 Responses to “Danger Danger”

  1. Thanks for following up. Interesting read. I can imagine the situation: for what I’ve seen from the passenger seat, sunrays mixed with rain and clouds can produce some really bright reflections pointing straight to your eye. A sunset visual is pretty bad when driving a car, too, so I should know. Yet I was surprised to hear about it here. It’s easy to assume that the sun wouldn’t be a problem since planes have done ILS landings at nighttime for decades. What could be worse than seeing nothing much but darkness? Well, I now know better. I’d love to read more, should you find another inspiration to write.

    Anyway, yours is indeed a good blog — I’m glad I found this site.

  2. Nothing but darkness isn’t really so bad compared to some of the weird stuff we see on occasion.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: