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One can notice the forward fairing of pylon is very shiny and metallic. This is quite unique and I do not find it in other aircraft. Why is this?

Does it serve any specific aerodynamic purpose or does it house any anti-icing provisions?

a350 zoomed in

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  • $\begingroup$ I don't really know the answer but if you note, all the other "leading edge" surfaces on the A350 are unpainted. That part appears to be a leading edge also. The nose is not a painted metal object but rather a plastic radome that likely has the color embedded in it. My theory is that they leave these unpainted so that you don't get a ragged effect as the paint wears or chips off over time. $\endgroup$
    – jwh20
    Nov 15, 2022 at 21:37
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    $\begingroup$ It is definitely the first panel of the engine pylon and is indeed left unpainted. Would be interesting to know why. $\endgroup$
    – sophit
    Nov 15, 2022 at 22:45
  • $\begingroup$ @757toga from this picture it seems to be riveted. $\endgroup$
    – sophit
    Nov 16, 2022 at 11:05
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    $\begingroup$ It's not heated. It's probably made of a material that is difficult to obtain paint adhesion, say titanium or some grade of stainless, or doesn't need paint because it's a corrosion resistant material and they are saving a few ounces, or some other reason known only to insiders. $\endgroup$
    – John K
    Nov 16, 2022 at 13:42
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    $\begingroup$ Titanium requires elaborate processes to get paint to stick, acid etching, sometimes sandblasting. They may just leave the paint off BECAUSE it's titanium or stainless (more likely) so they can leave it unpainted without worrying about corrosion. $\endgroup$
    – John K
    Nov 16, 2022 at 17:55

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You figured it out when you wrote the question. It's because the engine nacelles are equipped with anti-icing heaters powered by air from a compressor port, and painting those areas would be counter-productive. Same with the inboard sections of the wings.

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  • $\begingroup$ Are you saying that the small square dark area pointed out by the OP functions as an engine nacelle anti-ice heater? $\endgroup$
    – RTO
    Nov 16, 2022 at 0:49
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    $\begingroup$ According to the ice and rain protection scheme for the A350-900, with respect to the engine and wing protection, the engine nacelles' air intake (lips of the nacelles) and slats 3, 4 and 5 (outboard of the engines) can be heated (for anti-ice) by bleed air. $\endgroup$
    – RTO
    Nov 16, 2022 at 2:38
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    $\begingroup$ Can you update with relevant sources @JuanJimenez? I tried to look up and found what @757toga says is correct. I cannot find any pylon heaters but only nacelle heaters. smartcockpit.com/docs/… $\endgroup$ Nov 16, 2022 at 5:48
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    $\begingroup$ You won't get ice accretion on areas like that unless it's runback ice and cowls are usually evaporative heating to prevent that. The A350 anti-ice system description doesn't mention a heated panel. $\endgroup$
    – John K
    Nov 16, 2022 at 13:33
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    $\begingroup$ @JuanJimenez But the A350 is powered by RR Trent XWB, not GE engines. I haven't seen this part unpainted on other RR Trent engines, or any GE engines for that matter. $\endgroup$
    – Bianfable
    Nov 16, 2022 at 16:31

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