08 September 2007

Which runway? Where’s the windsock?

Like me, you were probably taught to fly over an uncontrolled aerodrome above circuit height to get a look at the runways, look for traffic and to see which runway the windsock indicates is most aligned with the wind. To do this, I was taught to cross the airport five hundred feet above the circuit altitude. That puts me fifteen hundred (1500) feet above the runways and the windsock. I should be able to see the windsock from here, eh? Actually no! Canadian regulations require a wind direction indicator that is visible from an aircraft at one thousand feet (1000) above the windsock, i.e., normal circuit height.

In short, Canadian Aviation Regulation 301.06 calls for a wind direction indicator to be a conspicuous colour, cone shaped and visible from an aircraft flying at 1000 feet above the indicator. I guess it's just luck that all these years we have been able to see the windsock from 1500 feet.

I ask, should Transport Canada amend the regulations and standards to fit reality?


From the CARs

301.06 (1) Except where the direction of the wind at an aerodrome can be determined by radio or other means such as smoke movement in the air or wind lines on water, the operator of the aerodrome shall install and maintain at the aerodrome a wind direction indicator that is

(a) of a conspicuous colour or colours;

(b) in the shape of a truncated cone;

(c) visible from an aircraft flying at an altitude of 300 m (1,000 feet) above the wind direction indicator; and

(d) illuminated when the aerodrome is used at night.

(2) When an aerodrome is closed permanently, the operator of the aerodrome shall immediately remove all of the wind direction indicators installed at the aerodrome.

From Canada’s AIM

(iii) If it is necessary for an aircraft to cross the airport before joining the circuit, it is recommended that the crossover be accomplished at least 500 ft above the circuit altitude.

From Aerodrome Standards and Recommended Practices, TP 312

The colour or colours should be so selected as to make the wind direction indicator clearly visible and understandable from a height of at least 300 m, having regard to background. Where practicable, a single colour, preferably white or orange, should be used.


Anonymous said...

Actually I can see the socks just fine from 1500 feet. Maybe is is your glasses?


Lloyd G Bunbury said...

Hey, it's 2007 guys! Why not have an electronic device that broadcasts the wind direction and speed on the airport frequency if you key the mike "x" number of times!

Lloyd G Bunbury said...

Hey guys, it's 2007 already!

How about we install electronic devices that will broadcast the wind direction, speed and altimeter setting on the aiport frequency if you key the mike "X" number of times kind of like enabling the runway lights.

Michael Shaw said...

I agree, an electronic wind indicator, is a great idea. ASOS, AWOS, and other automated systems do pretty much as you suggest. Most will broadcast on VHF and many also are accessible by phone, in the USA anyway. They tend to be expensive, especially if they are used to report official weather observations. That said, maybe someone will come up with an inexpensive electronic device (say using LED lights) aimed at visually displaying wind direction and speed. It could be left on all the time? Then aircraft without electrics could use it too, and it would be work day and night. There is a project for you...

Thanks again for your comments.

Michael Shaw

Frank Hofmann said...

Ah, the good old days when we had a 'Wind Tee', a big orange and white airplane-like contraption which was cranked around to indicate the runway in use. Great for no-wind or 90 degree crosswind situations. Unfortunately it didn't tell you what the wind actually was, but there was no confusion over which runway to use.

Good luck with your site. Good idea. Come visit mine at www.hoftec.blogspot.com