As mentioned in a sister post, I've just begun my ski flying career. Had a beautiful day, broken sky and did a bunch of touch and go's on my first lake. Local conservation officer snowmobiled over to visit and gave me a tip on a nice remote lake nearby with thick, safe ice. Headed south and sky went solid overcast. On approach in, I could not believe how dramatic the flat light effect really is. I could not see ANY lake features. Fortunately, I recalled reading about watching the shoreline as you descend to get your bearings, so was a firm but not dramatic landing. What bugs me is that I could not see definitively what I was landing on. I thought wearing my amber colored ski goggles would help, but they did squat.

Anyone find any lens products out there to enhance depth perception in flat light conditions?

Back when I used to ski and when I go sleddin I find yellow lens in the googles help me a ton is reading terrain... The bad part is that color gives me a headache...... fast. Research it and buy some googles and keep them in the plane for flat light days...

Stol wrote:Back when I used to ski and when I go sleddin I find yellow lens in the googles help me a ton is reading terrain... The bad part is that color gives me a headache...... fast. Research it and buy some googles and keep them in the plane for flat light days...

Glad to hear yellow was a solution for you. I'll double check the color on my goggles. I said amber but now not sure what tint they are.

Smith Optics make great glasses and goggles.

Check this out...Dont think this working but just go to the Smith site and look at "Lens Selector"

http://www.smithoptics.com/

[img]
PHOTOCHROMIC RED SENSOR
VLT: 20-50%
Combining our proprietary Red Sensor mirror outer lens with a revolutionary, new visible-light activated photochromic inner lens for all day riding in varying light conditions.

IGNITOR MIRROR
VLT: 35%
Proprietary universal lens tint designed to reduce eye fatigue while enhancing contrast and depth perception in all conditions. A versatile lens tint designed to be used all season long

RC36
VLT: 36%
The universal lens tint. Combines rose and copper base tints. Provides the absolute best vision in most conditions. Increases depth perception and cuts glare in all conditions.

RED SENSOR MIRROR
VLT: 60%
Light rose base lens tint with a multi-layer red mirror maximizes color definition and increases depth perception in varying levels of flat light conditions

BLUE SENSOR MIRROR
VLT: 70%
Light rose base lens tint with a multi-layer mirror maximizes color definition and increases depth perception in varying levels of flat light conditions[/img]



Lens choice above also applies for glasses.
http://www.smithoptics.com/products/#/sunglasses/New+Releases/

AKT

I prefer rose tint for flat light and improving depth perception. My wife is blind in one eye (non-existent depth perception) and found that the rose tint helped her immensely when skiing or snowmobiling.

My experience is that "blue blocker" type glasses work for me. I have prescription glasses tinted a rosey/brownish color that are great. But tinted optics don't work for everyone.

There is a good video on flight light and whiteout flying. Not sure if it's done by the FAA or the Medallion Foundation, but can get the details for you if you can't find it on YouTube.

Eric

aktahoe1 wrote:Smith Optics make great glasses and goggles.

Check this out...Dont think this working but just go to the Smith site and look at "Lens Selector"

http://www.smithoptics.com/

[img]
PHOTOCHROMIC RED SENSOR
VLT: 20-50%
Combining our proprietary Red Sensor mirror outer lens with a revolutionary, new visible-light activated photochromic inner lens for all day riding in varying light conditions.

IGNITOR MIRROR
VLT: 35%
Proprietary universal lens tint designed to reduce eye fatigue while enhancing contrast and depth perception in all conditions. A versatile lens tint designed to be used all season long

RC36
VLT: 36%
The universal lens tint. Combines rose and copper base tints. Provides the absolute best vision in most conditions. Increases depth perception and cuts glare in all conditions.

RED SENSOR MIRROR
VLT: 60%
Light rose base lens tint with a multi-layer red mirror maximizes color definition and increases depth perception in varying levels of flat light conditions

BLUE SENSOR MIRROR
VLT: 70%
Light rose base lens tint with a multi-layer mirror maximizes color definition and increases depth perception in varying levels of flat light conditions[/img]



Lens choice above also applies for glasses.
http://www.smithoptics.com/products/#/sunglasses/New+Releases/

AKT

AKT: which Smith lens do you have hands-on experience with and use for flat light flying? thanks.

Apart from glasses, landing technique in those conditions should be the same as for a glassy water landing on floats. And it's not unheard of to pitch stuff out of the plane for ground reference at your landing site.

-DP

DP is right, a couple of evergreen branches or even a jacket or two thrown out on the snow really help.

Like Aktahoe1 said...there's a wide array of lenses using new technologies (beyond just yellow tint) to improve surface contrast. If you have flat light, you have flat light. The main variable at that point is light intensity. Running a pair of lenses without enough tint on a flat, intense light day is hard on the retinas.

I use the Ignitor Sensor lens on stormy days, but carry a regular pair of amber lens goggles in my pack to swap out to if the sun peeks out.

macktruckfarm wrote:DP is right, a couple of evergreen branches or even a jacket or two thrown out on the snow really help.

Or carry some purpose-built ejectiles (is that a word?) made from day glo ribbon with a small weight to get it to drop quick.

Thanks for replys guys and looks like I'll be investigating Smith products. Although, lack of ground reference was striking (sorry), it was my inability to discern surface features that really bothered me. I never want to find myself in the position again of landing blind on a remote foreign lake. Surely, optics technology has come far enough to solve this. If not, then I'll forego the flight.

A friend regularly lands on glaciers, often in flat light. He uses Kool Aid to mark the surface. I assume he is buying it in bulk and repackaging it into plastic bags. I'll ask him next time I see him. I know he also uses weighted trash bags

PA12_Pilot wrote:A friend regularly lands on glaciers, often in flat light. He uses Kool Aid to mark the surface. I assume he is buying it in bulk and repackaging it into plastic bags. I'll ask him next time I see him. I know he also uses weighted trash bags

Plz do, would really like to know what the pros are wearing.

Do not believe for one moment that ANY kind of glasses will allow you to see contrast in true flat light.

There are two issues with flat light and airplanes:

1) Fly a "glassy water" type approach, and you may unfortunately find out that that snow is not only hard as concrete, but it's also REALLY rough. I broke an axle on one of those deals, and spent the night out in really cold temps as a result.

2) There can be things on lakes other than drifts that can break that airplane or its landing gear. Things like the piles of slush ice fishermen leave, and that freeze, things like beaver houses, etc.

To paraphrase the Great Yogi Berra, "You can't see what you can't see". And, if you're hurtling along at 45 mph when you hit it, whatever "it" is, something is very likely to break.

I was doing a recurrent ski check ride and SEL ride once south west of FAI in a 185 on wheel skis. The weather was 3 or 4 K over, but visibility was hovering between 1 and 3 miles. It was winter, so very low sun angle, though mid day. Check airman pointed out a lake and said land there. I flew over the landing zone, checking it out, came back past it on a very close downwind, turned around and landed. Turned around and took off opposite direction. He told me to do that again, and I did, only this time, he told me to taxi back to where I'd touched down and take off the same direction I'd landed. As I taxiied back to my touchdown point, we both saw a huge beaver house at the same time, and it was just beside where I'd been landing. Neither of us had seen it on those two approaches or during the brief recon. It was nearly invisible, covered with snow. Took off, flew past the thing three or four times and we could just barely make it out, if we knew where to look. A very graphic illustration of real flat light.

There is flat light and there is really flat light, though.

Flying on a sunny day, and fly over into some shadows from hills, and you may encounter flat light, though the visibility there is not too bad.

Low sun angle, as in far north in mid winter or late or early in the day down south will give you flat light. Add a cloud cover to that, and you're starting to get REALLY flat light. Now, add some obstruction to visibility to that, and you have a recipe for disaster if you're trying to land a ski plane.

When I had a cabin on a lake southwest of FAI, first job after freeze up was to go down there and stick spruce branches into the snow to mark the airstrip out, since it was on a fairly small lake. Then, if vis was low or cloudy or.... I always had a visual reference for finding the strip. That lake sat in a small bowl, so didn't get drifted real bad usually.

Some lakes consistently drift on one side or the other, and those drifts, once they've set up, can take the gear off any airplane ever made.

Be careful out there. Glasses MAY help a little, but this isn't snow skiing or snowboarding. You're a little farther away from the snow, and moving pretty fast. And, your legs can probably take more moguls than your airplane's gear can.

FWIW,

MTV

mtv wrote:Do not believe for one moment that ANY kind of glasses will allow you to see contrast in true flat light.

There are two issues with flat light and airplanes:

1) Fly a "glassy water" type approach, and you may unfortunately find out that that snow is not only hard as concrete, but it's also REALLY rough. I broke an axle on one of those deals, and spent the night out in really cold temps as a result.

2) There can be things on lakes other than drifts that can break that airplane or its landing gear. Things like the piles of slush ice fishermen leave, and that freeze, things like beaver houses, etc.

To paraphrase the Great Yogi Berra, "You can't see what you can't see". And, if you're hurtling along at 45 mph when you hit it, whatever "it" is, something is very likely to break.

I was doing a recurrent ski check ride and SEL ride once south west of FAI in a 185 on wheel skis. The weather was 3 or 4 K over, but visibility was hovering between 1 and 3 miles. It was winter, so very low sun angle, though mid day. Check airman pointed out a lake and said land there. I flew over the landing zone, checking it out, came back past it on a very close downwind, turned around and landed. Turned around and took off opposite direction. He told me to do that again, and I did, only this time, he told me to taxi back to where I'd touched down and take off the same direction I'd landed. As I taxiied back to my touchdown point, we both saw a huge beaver house at the same time, and it was just beside where I'd been landing. Neither of us had seen it on those two approaches or during the brief recon. It was nearly invisible, covered with snow. Took off, flew past the thing three or four times and we could just barely make it out, if we knew where to look. A very graphic illustration of real flat light.

There is flat light and there is really flat light, though.

Flying on a sunny day, and fly over into some shadows from hills, and you may encounter flat light, though the visibility there is not too bad.

Low sun angle, as in far north in mid winter or late or early in the day down south will give you flat light. Add a cloud cover to that, and you're starting to get REALLY flat light. Now, add some obstruction to visibility to that, and you have a recipe for disaster if you're trying to land a ski plane.

When I had a cabin on a lake southwest of FAI, first job after freeze up was to go down there and stick spruce branches into the snow to mark the airstrip out, since it was on a fairly small lake. Then, if vis was low or cloudy or.... I always had a visual reference for finding the strip. That lake sat in a small bowl, so didn't get drifted real bad usually.

Some lakes consistently drift on one side or the other, and those drifts, once they've set up, can take the gear off any airplane ever made.

Be careful out there. Glasses MAY help a little, but this isn't snow skiing or snowboarding. You're a little farther away from the snow, and moving pretty fast. And, your legs can probably take more moguls than your airplane's gear can.

FWIW,

MTV

Thx, MTV, your admonishments are exactly what I want to defend against. Care to weigh in w/ your 30 yrs experience on my other overflow thread?

Winter things that bust gear...



Some people will throw pine bows out to mark the snow, others will throw a dead seal...

It's not just lake surfaces that disappear. Whole mountains go poof in true whiteout conditions and wait for you to run into them. Or that row of willow branches you laid out the day before on your snow machine to use for depth perception, suddenly becomes the horizon as you look at it from the air. Only problem is, it's at a 60 degree angle to the true horizon and you screw the airplane into the ground trying to figure it out.

That crap is a real killer of pilots.

Gump

BRD wrote:Winter things that bust gear...



Some people will throw pine bows out to mark the snow, others will throw a dead seal...

BRD: Up in my neck of the woods, that pile of ice cuttings is what I worry about most. Ice fishing is the number one winter sport up here. The holes are also a great source of overflow.

Ordered up a pair of Smith goggles with a red sensor mirror lens today for $50. Not too bad a price. Will report back on flat light performance.