OK, I’ll bite.:)

As you know, in aviation we generally pride ourselves on discovering the causes of accidents or almost-accidents, so that whatever the reasons were, lessons can be learned. The crew will only “get into trouble” if they deliberately do something wrong, e.g. refuse to de-ice. Wing upper surfaces must be completely clear of contamination. Are they? Difficult to tell from the photo, but I can see white patches which can only be frozen water of one kind or another.

Remember the Potomac river disaster, where there were a whole catalogue of errors in icing conditions.

The passenger was truly concerned but did not know what to do or who the relevant authorities are and is trying to find out.

”Captain, there is still ice on the top of your wings”...................

It might be ice, it might be not. I have it many times these days that the fuel temperature is around 1-2 degrees, we have some moisture in the air with low temperatures close to freezing and the only thing you find on the wing is a thin layer of water. Maybe the crew had somebody do a clear Ice check and they didnt see the necessity for a de-ice.

Or, alternatively, it could pressure the pax to not say anything. Who wants to be off-loaded on the last flight of the day....

*I* would - if I had seen ice on the wings and believed the crew was ignoring it. I'd rather be alive and stuck somewhere an extra day.

It’ll be OK. Just a bit of frost.

N90AG

The AAIB report on N90AG at BHX makes for a sobering read.

Never let a crew take you to the end of the runway with ice on top of the wings.

What's your point? It's snowing out.It happens often

Wings covered with snow and no anti-ice fluid.

China Airlines 747 takeof with apparantly contaminated wing
 

This video was posted on this thread.

Is China Airlines exempt from the clean wing policy? Is there something I'm missing here?

There’s a lot of information we don’t know. When was it de-iced. What was the fluid mix. What was the holdover time. In heavy precipitation the wing could well have snow on post de-icing but still be protected. I doubt they would have departed in those conditions without having considered winter SOPs.

It’s difficult to see what’s on the wing. How can you tell they haven’t been de-iced from that video?

No.
If the treated surfaces starts to collect snow, the anti-icing is no more.

I'd be curious to know what the reported visibility was. Even if the critical surfaces had been treated, which is far from obvious, the snowfall intensity seems likely to be in excess of anything for which there's a published holdover time.

It certainly looks scary. We should remember, though, that the video was shot though a long (telephoto) lens, which compresses whatever is in the air between camera and subject. Still, there's obviously a lot of snow falling.

Airbus can have hoarfrost on the top surface of the tanks with cold soaked fuel, even on a 20C day, and many A types are approved for takeoff in that condition as the chief pilot of a former employer advised me after I put in a query. Of course lift from that small section of the wing is next to nothing, but the rest of the wing still works.

Dry snow accumulation on an already cold wing during taxi with air temperature below 0C will blow off.

Other cases can be problematic.

There are combinations of wing, air and precipitation temperature that demand de-icing with a holdover time, generally when the precip sticks to the wing. I remember being seated over the wing. We were de-iced at the gate in ORD and joined the conga line. In the early takeoff acceleration, the entire blanket of snow slid off the wings and joined the pile left by departing aircraft.

Everything above 0C is good as is everything well below 0C.
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