Friday, September 25, 2009

Silent But Deadly

I take off and get clearance into the overlying class C airspace, then continuing eastbound I clear the zone. I tell the controller that I'll be returning in about six hours and ask if I should keep the transponder code. He replies enthusiastically in the affirmative and clears me en route.

Ahead and above I see an airplane, about Dash-8 proportions, on a trajectory that will bring it into Edmonton. It's not that far above me and I'm surprised that the terminal controller didn't point it out to me before clearing me en route. They usually point out airplanes you can see, even if they aren't a traffic conflict. In the same instant that I see it, I suddenly realize that my initial understanding of the perspective was completely wrong. It isn't a larger fast airplane far away. It's a glider, right there, moving slowly, just above me, and there's another one below and to the left. They are white with no markings, making them harder to see against sky. Perhaps they were below my field of vision a moment ago. I dodge right and flash past them, wondering if they saw or heard me. I almost hope not. I imagine it's hard to change your underwear midflight in a glider.

I have engines and they don't, so they have the right of way, and of course I willingly cede it, but that was close. Had I struck one, it would be lucky (like this case) if either of us had survived. Aircraft are designed to withstand weather and normal inflight stresses, but not impacts. See and avoid is the rule, but you have to see first. I actually knew there were gliders in the area, because I read the CFS entry for the airport, when I was looking for possible alternate landing and fuelling spots. And today is a Saturday, so the weekend flyers are out.

I made a call on the frequency of the glider port and on 126.7, but never heard any glider traffic, and I never saw a glider there again, even though I was back and forth over that spot several times on the weekend. Perhaps they didn't have electrical systems, so no transponders or radios. I guess that's a lot of weight for a glider to carry, too.


Anonymous said...

Unfortunately gliders don't always appear on the radar because they are too small and don't have transponders (usually). The glider areas can be shown on controllers' radar screens and we try to keep any planes clear, but the gliders don't always stay in the area or below the altitude that is notam-ed. I'm always a bit paranoid when the glider area is active and try tell any planes in the area about it, but I can only do that if I'm not busy.
- a low level ATC

Unknown said...

If they were white, eg. gelcoat gliders they are probably somewhat more modern than your average american glider. Weight of com's and xdpr shouldn't be an issue for a modern glider, however especially the transponder consumes a lot of energy. Usually, glider pilots want to preserve that energy for the navigational aids like the GPS and pocket PCs.

Beautiful aircrafts though, aren't they? =)

/Magnus (glider pilot)

Sarah said...

Magnus, I'd say 90% or more of US or Canadian gliders are glass fiber European or Eastern European imports. The old metal Schweizer 2-33 trainers you're probably thinking of are slowly disappearing.

I fly a LS 6 myself.

Caution: longish reply to Aviatrix' post on the way.

Sarah said...

First, Silent but Deadly? As a glider pilot, I really must complain about the post title. It makes us seem more like flatulent gas producers than the pilots of elegant and beautiful aircraft.

I don't know about Canadian custom, but in the US we commonly use 123.3 for air-ground or air-air position reports. We may tell each other when we've rounded turnpoints, reassuring each other the trailers don't need to roll for a retrieve quite yet. Or, if several are in the area, position and intent so we can join or avoid each other.

Gliders are very hard to see unless they are turning, and as you say, being all white against cloud it's not easy even then. The closest call I ever had was spiraling up under a cumulus cloud. I caught a flash of green in the corner of my eye and looked left and down to see the local school C-150 flash underneath less than 200 feet away. There was no time to do anything, except be glad I had been climbing well.

These days, nearly all gliders have radios, but except around high traffic areas like KMEV or KLAS they are unlikely to have transponders. The issues are cost, panel space and electrical load, probably in that order. A xpndr installation is likely about $2000, and when your whole aircraft may cost only $10-20k, $2k plus biannual maintenance is a bitter pill to swallow. Still, I'm considering it. The TRIG TT-21 is intriguing.

Meanwhile, I've been flying with a transponder detector PCAS for a couple years. It is amazing how many aircraft it points out, and it's amazing how hard I will look for an unknown aircraft "0.5 miles 0 feet relative altitude."

Unknown said...

OK, sorry. It's been a while since I flew in the states =)

Sarah said...

Last comment, I promise.

I didn't mean to be "too" funny or about the post title. The issue is a life and death situation for our favorite Aviatrix I take very seriously, and I'm sorry the encounter was dangerous.

But as in all aviation, there is a balance of assumed risk and operational decisions we all make. We all try to do the right things, within limits. I'd be interested in any suggestions on radio or other protocols anyone thinks may help avoid collisions.

Rhonda said...

I remember leaving the control zone on one solo flight and when giving me traffic information, the controller included a comment on a primary radar blob below me: "possible ultralight or flock of birds." I never did see anything there.

david said...

Why are gliders not painted in strong, contrasting colours to make them move visible? Is it just the weight of the extra paint?

nec Timide said...


Some are.

The plastic ones are white for the same reason Katanas and SR22s are. Heat can reduce the strength of composite materials over time, white paint help keep them cool.

Sarah said...

Right, NecTimide. It will be interesting to see the paint jobs the Boeing 787 gets. Perhaps new materials are better than we think.

Any comments on glider radio usage in CA? Is 123.3 the standard there too?

nec Timide said...

There is a lot of glider activity around my local area, that also includes a moderately busy terminal area. I had a long three way conversation between the glider pilot, ATC and myself. I did finally spot the glider, or rather a tiny bit of moving white on the stationary white background, and we were never closer than about 1/2 mile. 123.45MHz is used, but most radio equipped gliders seem to be on their ATF unless on cross country or talking to ATC.

david said...

Thanks for the explanation. The heat problem makes sense, but there must be some kind of work-around.

Flying near an airport in a white glider sounds a like like riding a bike on a highway at night with no light or reflector, dressed all in black.

Sarah said...

@David, there is a workaround.

I believe anti-collision markings on non-structual areas like this are required in Germany, Holland, possibly other EU countries as well.

It's not unusual even in the US for gliders to have colorful red or blue nose and tail for this purpose.

Even white only, it's not as bad as black at night. Pure white shows up pretty well against the ground or blue sky.

david said...

@Sarah: I have managed to spot gliders once or twice in 700+ hours of flying, but I'm sure that for every one I saw, there were 10 or 20 that I didn't.

To be fair, it's also pretty hard to spot a Cessna 150 a half mile away, especially if you're at the higher altitude.

Anonymous said...

Depending on how close you were, they probably heard you. The gliders motion in the air while not as silent as most imagine, is very quite in comparision to a prop plane. Glider pilots don't wear headsets, and can have conversation with each other in a normal tone of voice.

Nothing like the sound of an engine to get a glider pilots attention. Usually when over the airport I can hear departing prop planes up to around 3,000 AGL.

When on tow, the tow plane at 200' in front of you makes quite a noise. One day after tow release, instead of it getting quieter, I heard a Helicopter nearby. Turning my head and the glider try as I might, I could't see the helicopter. I was managing to avoid it none the less. Of course once the sound level didn't begin to change it dawned on me that it was a piece of gap seal tape that had come loose in the slip stream just next to my ear. It sounded like a Huey as it flapped away.

Let's just say it was memorable.

As always, see and avoid starts by looking, and you got to go home(back to hotel) at the end of the day, so cheers!

verification word; hydrifet

We haven't had much rain round these parts since June, so finally I got's "hydrifet"

Anonymous said...

wrt colors other than white on FRP/CFRP parts and the 787, it is worth noting that gliders are often built in rather ad hoc manufacturing situations (garages, cottage industry shops) and the parts are cured at or near ambient temperatures and pressures.

epoxy resins tend to lose strength most quickly at temperatures beyond what they were cured at.

787 structural bits are cured in very large, very expensive autoclaves that apply much heat and pressure to the process.

that said, I have not seen a 787 painted a dark color on upper surfaces...

Jim said...

I fly in the same area as nec timide, and there is a large CYA just south of YOW for RVSS, and a good number of gliders also fly to the east of YOW for the GGG [in celebration of Trixie's TLA posting!!]. That said, I have not managed to see gliders in the air, and only infrequently hear them on the radio (YOW terminal telling Tim to stay below 4,000' ie. out of controlled airspace).

Gliders tend to be minimal-equipment units - ASI, VSI, compass, and usually a radio. Transponders use lots of power (they transmit at every illumination by radar), and a mode C requires an altitude encoding altimiter (more power). Best tactic for a glider pilot is to broadcast frequent position reports. On more than aerodrome frequency.

Last time I flew through Kars airspace terminal asked me to do a position report on the Kars frequency. There was a glider on the button on the runway and no tow plane in sight, whihc made me think there was a towplane and at least one glider in the air. I made radio calls, but the frequency was silent. Both of use were eyes-open as we transversed the area.

Trixie, I am in Calgary for most of the coming week.

A Squared said...

Anonymous posted: that said, I have not seen a 787 painted a dark color on upper surfaces...

Ummm, given that Boeing hasn't ever *flown* a 787, let alone delivered one, I have to ask, exactly how many 787s have you actually seen?

Critical Alpha said...

I can imagine your heart rate Avi!! I learned to fly in gliders and lots of the old Blaniks were painted with visibility in mind. Later in powered aircraft I had an instructor who would create an instant diversion at the mere thought that there might be gliders operating at the destination airfield. He'd begin muttering "can't see the b#$%" and shaking his head. Nothing would induce him to go near gliders.
This is a subject close to my heart as a cousin of mine was killed in a mid-air last year - between a powered a/c and a helicopter. Lucky near miss Avi!
The ATSB in Australia did a report on the limitations of see and avoid. Pretty sobering reading:


Critical Alpha said...

Sorry - that URL should have


added to the end of it.


Anonymous said...

An increasing number of gliders in Europe now has a low-power GPS-based Collision-Avoidance system called "FLARM". It transmits data about the calculated flight path to other FLARM boxes in the vicinity (ca. 5 km). If there is a risk of collision, both FLARM will sound an alarm and display information about the position of the other aircraft.

Apart from gliders, other light aircraft and helicopters are starting to install these systems, too. They really are a great help for locating other gliders on days with lots of "silent" traffic.