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Here are a couple of examples: enter image description here

enter image description here

Rodrigo de Azevedo
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yippy_yay
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    This is a guess but I'd suspect it has something to do with radar. – GdD Jan 27 '15 at 16:24
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    I think this question could be enhanced with some recent photos of newer planes that do not feature such a black nose, which undeniably exist. There are already some answers now that just state some planes now also have black radar domes, which is certainly true, but does not address your perceived transition from "most airliners have black noses" to most airliners having their noses coloured the same as the rest of the hull. – O. R. Mapper Jan 28 '15 at 11:05

3 Answers3

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Under the nose of modern airliners is weather radar that helps the crew to see and avoid hazardous weather conditions. This is required by FAA CFR §121.357 for transport category aircraft. The radar signal would be blocked by the aluminum that makes up the rest of the fuselage, so the radome is made of a non-metallic material, generally a fiberglass composite.

These threads discuss the topic. The last post in the first linked thread suggests that most paint needed lead to prevent fading and/or a zinc-based primer, which would interfere with the radar. Black was one color that did not require these. Modern paint has done away with these metal additives, allowing more color options without interfering with the radar.

The Museum of Flight claims that the black color is only to remind crews to not paint over the radome. Painting over it would affect the radar signals.

According to this thread, the color of the radome affects the operation of the weather radar underneath. They were painted black because it has the lowest reflectivity. Modern radars are able to deal with different colors much better.

fooot
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    Your last paragraph is extremely dubious. I'd guess that because radar-transparent paints were developed, probably using titanium instead of lead, that it no longer was an issue. That different colors matter is tenuous; the hard part is getting a very bright, opaque, white base to the paint. – Nick T Jan 29 '15 at 01:55
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    @NickT thanks for the tip, I included a couple of better references to that point. – fooot Jan 29 '15 at 22:28
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Because the nose of the plane is where the weather radar antenna is, and paint would interfere with the signals.

This is not just the 60's and 70's, and its not only on the nose. Here's a brand new PC-12 with a radar dome (radome) on the right wing, painted black:

enter image description here

Inside of the radome is a radar array that can be tilted and panned using a control inside the cockpit:

enter image description here

This is the pilot's view inside the cockpit, which shows the knobs used to adjust the pan/tilt, range, and sensitivity:

enter image description here

And you can read a brochure about a particular aviation radar system here.

rbp
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    "Brand new PC-12"? Look at all those interior scratches! – Lightness Races in Orbit Jan 28 '15 at 15:05
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    that interior is not from the PC-12, anymore than the nose cone radar array is. – rbp Jan 28 '15 at 15:11
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    Is it just me or does the last image look like it was taken from a video game? Look at all those screws completely lacking any depth at all. – Chris Feb 05 '15 at 20:09
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    @Chris It looks like it's from 727 Captain. – Kelly Thomas Jul 14 '15 at 05:03
  • @rbp Isn't the antenna in your middle image a phased array antenna? Isn't the point of such that it can transmit in different directions (and receive the echo from that direction) without being physically rotated? But I guess there is a low limit to the deflection that can be achieved, and sometimes one would want to check the weather further up/down/sideways, too. Anyway, back in the 60s and 70s, that the question is about, there were no phased array radars, right? The weather radar in aircraft had a traditional antenna continuously moving from side to side (and up and down), right? – tml Apr 12 '22 at 08:29
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It is called a nose cone.

There can a several reasons (as mentioned here and here):

  • Aircraft used to be painted with a lead-based paint, which is unsuitable for radomes. Instead, they had a rubber coating. Nowadays, the paint used (epoxy on military planes, I believe) won't affect the radar.
  • It's as much a fashion statement as anything else
  • It started out as an anti-glare panel. The fuselage within pilot's view is painted dark and of matte finish to reduce the chance of any glare that might obscure pilot's vision.

Even today, you can find some military aircraft with a darker nose cone.

Farhan
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  • This RC-12K is a great example of a military aircraft with a black nosecone and anti-glare on the inner engine cowlings and in front of the windscreen. – Erich Jan 29 '15 at 23:39