The two sides of the plane were de-iced with different de-icing mixture percentages. And the mixture dispensed was different from what it was labelled (18 per cent actual vs. 30 per cent selected).

The operators of the de-icing mixture had no way of knowing the accuracy of the fluid being dispensed as an incorrect nozzle was installed, one without a "mix monitor."

That simply isn't done today, at nearly any carrier. 75% of deicing tends to be engines RUNNING now, and either way there are very limited circumstances where cabin checks are made, typically involving very heavy ongoing preciption that is likely to overcome the deicing on the way to the runway. I'm glad you did it your way, but that is NOT the way it has been done in my 25+ year career.

This is what is in my last Airlines Ops manual.

https://cimg7.ibsrv.net/gimg/pprune....9e620a9ad.jpeg
https://cimg8.ibsrv.net/gimg/pprune....82cc8f191.jpeg

Can't speak for all of them but it was my regular practice to do a side to side visual sweep of the cabin (including out the windows) as a sort of double cabin secure)check on my way to my jumpseat.

When seated forward, it was particularly effective at catching out the wiseass pax who thought they could get our their bags/laptops after I'd done the cabin check.

Twice during such I noticed issues, once what appeared to be a fuel leak and the second what looked to me "not right" after de ice
I'm sure many of my colleagues do the same as a standard practice

Why don’t you all just follow your company Standard procedures with respect to pre takeoff…….worked for me.

Wool tufts
 

My outfit had them installed onto the inboard top of the wing so that we could inspect them through the cabin windows which were especially handy for clear ice.
I was sent forward whilst dead heading by my skipper between GVA and ZRH on a North African carrier as he had spotted a sheet of clear ice caused by cold soaked fuel with relatively high humidity and temperatures in double figures; it had been missed by our engineers.
We had a German skipper imprisoned in Anchorage after he climbed onto the wing of a local carrier after the crew refused to de-ice the aircraft that was covered in dry snow.
My next trip there I witnessed one of their aircraft disappear in a cloud of snow as it rotated and the airflow change dislodged the snow on their wings. Normal ops don’t clear dry snow. Never flown with them nor will.
Only ever had one disagreement after we had passed hold over times with a skipper who was a big cheese in the military and refused to return, I re checked the wings and decided that it was time to threaten standing on the brakes time but ATC closed the airport before we were cleared to line up.

I remember having this discussion with a South European airline captain, he insisted de-icing was not necessary. We deiced anyway, pointing out the the UKCAA had not approved the procedure. This was well over 20 years ago so I've no idea if it was subsequently approved by EASA.

As pointed out, a cold soaked airframe just down from FL350 can develop frost over the fuel tanks in clear air. And fine drizzle can also get stuck all over a cold airframe.

There's three temperatures to keep in mind: Air, airframe (especially over tanks), precip.

Operators in Alaska have figured out that dry snow on a cold airframe doesn't stick. But watch out for an airframe just pulled out from a cozy warm hangar with snow coming down.

Airbus and Boeing publish guidance for frost over fuel tanks on various aircraft. The performance degradation has been found acceptable in these cases. We should also remember that certain deice fluids also come with a performance penalty.

Alaska
 

Maybe but you don't know until you rotate..the skipper concerned was a German 104 starfighter guy trained up by the US of A..his group were the best lot I flew with. After he was arrested they de iced..
There was a lot of odd ball flying out of ANC that I witnessed including a couple of sheets of ply strapped to the side of a Cub on floats.
Place full of fugitives from the lower 48 which made it interesting.

I often had problems getting de-iced at an airport close to New York where anything could happen during de-icing and often did. Procedures were rarely followed.
On one of the flights a cabin crew member called on the interphone and asked if de-icing was finished. It was just that she said she could still see snow and ice on the wing. The FO promptly said they would double check and headed down in to the cabin. Yes, there was snow and ice on the wing. So I asked to be de-iced again.
After that was finished I went down to check. The contamination remained. This resulted in a further request to be de-iced. This time I stood by the overwing exit to watch the de-icing. We finally taxied with a clean wing after a considerable delay.
My wife was on board and had witnessed the whole thing. She began to realise that some of the "horror stories" I had told her had some basis in fact.
We lived to tell the tale!

Excellent CRM from the cabin crew member! I wrote to her line manager commending her for her actions.

In cargo ops you can’t physically view the wing from inside the aircraft..757/767 dedicated freighters.

And when it does come off, and goes straight in the engines...

https://en.wikipedia.org/wiki/Scandi...tem_Flight_751

not very likely on a 320

Like BA/BY , had a lifetime airline LH and SH and retired 12 yrs . Airline practices have changed over time .
Seem to remember CDG was 1st in centralised deicing . The new Munich followed , all seemed efficient , and did not inspect from inside post deice ..taxi on to the Rwy and go . LHR always on the gate , and in olden days 7000L was used on LH 707 trying to de snow , de ice this Boeing block of ice . Us on SH were out on the wing with a broom and wellies ... de snowing before being de iced .. SH V. hot on deice post '58 Munich with Man U. 'Busby's babes' disaster on an Elisebethan .
Iberia cavalier , as on several occaisons , I've seen them taxying out with V heavy frost on wing . We would have deiced .. told them on radio , but they just blasted off. Embedded in Spanish culture perhaps , as MAD in heavy cold rain on cold soaked '75 . I as SFO asked for cherry picker so could check wing top for glaze ice , Capt was asked to confirm my request before action occured . Manyana was not in it to get deiced , included towing to eng. base , neither he nor I were best pleased .
SVO when our station eng. withdrawn , locals then checked deicing ... luckily one of the 'gurls was dating an F/O .. 1 wing deiced , the other Not .. back to stand and station eng. posted back .
2 more tales , fog closed Bangalore whilst on descent . Off to Madras before that shut with a supertanker load of gas on board . Hot moist on V cold wing.....
Us '' Deice please ''...
Ground Eng. '' Wait until the sun comes up and melts it '' !
Us , '' Ohh ! Ok ''
Gas 'n Go in Gander , January snow storm ,,, luckily a Tristar so Flt Eng. did outside chk. V cold , V dry snow , none of it sticking , so for 1st and last time . N need to deice .
Now ... still deicing PA28 'Cherrytrees 30 mins after sunrise for a days 'destructing .

Be aware , be suspicious and assume nothing when it comes to de-icing , it's your lives not the ground guys .

rgds condor .