AviRaider
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Intermittent Flashing Red Beacon On Aircraft

Thu Oct 18, 2012 2:26 pm

http://www.youtube.com/watch?feature=player_embedded&v=x-owRtLop08

So I was watching the video of American's newest 777-3 and I noticed that the flashing red beacon flashed intermittently and it didn't seem to have a pattern to it. I know there are all kinds of different types but specifically to the flashing kind, why is there no need for a consistent flashing of this beacon? Is there a reason that different aircraft have different flash patterns? I would think in this day and age studies would have weeded out the best beacon light types for safety.

Your thoughts?
 
vikkyvik
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RE: Intermittent Flashing Red Beacon On Aircraft

Thu Oct 18, 2012 2:35 pm

Quoting AviRaider (Thread starter):
Your thoughts?

Looks like the frame rate of the video simply doesn't pick up a lot of the flashes.

They do flash at regular intervals.
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rfields5421
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RE: Intermittent Flashing Red Beacon On Aircraft

Thu Oct 18, 2012 3:00 pm

The way electronic movie cameras capture images is very different than the way film captures images.

A film camper has a shutter - on a wheel for movie cameras.

When the shutter is open, all the light is available to expose the film.

With an electronic movie camera - the 'shutter' is open all the time, and the CCD is excited by the light. The camera reads scans of the CCD in a progressive order.

This makes some strange effects for fast moving objects like airplane props, and can also make lights which blink in a set pattern look intermittent.

See the prop on this aircraft - http://www.youtube.com/watch?v=6MpkvK2P2RM&feature=share

The same scan pattern issues cause the inconsistency you see in the video.
 
Goldenshield
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RE: Intermittent Flashing Red Beacon On Aircraft

Thu Oct 18, 2012 3:10 pm

Quoting rfields5421 (Reply 2):
With an electronic movie camera - the 'shutter' is open all the time, and the CCD is excited by the light. The camera reads scans of the CCD in a progressive order.

This makes some strange effects for fast moving objects like airplane props, and can also make lights which blink in a set pattern look intermittent.

This is why I when I use my camcorder, I love using 30 FPS progressive setting. Not only does it completely get rid of these flaws, but it delivers that old school film feel.
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AviRaider
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RE: Intermittent Flashing Red Beacon On Aircraft

Thu Oct 18, 2012 3:18 pm

Well that certainly all makes sense. I didn't think about it from the filming device's perspective. Thanks all.
 
JAGflyer
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RE: Intermittent Flashing Red Beacon On Aircraft

Sun Oct 21, 2012 1:02 am

The red flashing beacon on the top of the aircraft as well on the bottom is called the "anti collision" light.
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DarkSnowyNight
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RE: Intermittent Flashing Red Beacon On Aircraft

Sun Oct 21, 2012 12:15 pm

Interesting.

Anyone else notice that the UA 787 in the background is flashing with regular interval consistency? Do these CCD issues only apply at certain frequencies?
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yeelep
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RE: Intermittent Flashing Red Beacon On Aircraft

Sun Oct 21, 2012 3:13 pm

The 787 anti collision light may be consistently visible due to differences between the LED design on the 787, as opposed to a xenon flashtube design.
 
flood
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RE: Intermittent Flashing Red Beacon On Aircraft

Sun Oct 21, 2012 4:22 pm

The strobes on the 777 illuminate for a fraction of a second. If you're recording video at 30 frames per second and with a shutter speed of 1/60 for example (which is generally suited for 29.97 / 30 FPS), your shutter is only open half the time. That said, if the strobe happens to flash during a period when the shutter is closed, it's not captured by the camera.

The 787's LED "strobes" stay illuminated much longer, greatly increasing the likelihood of them being captured at such shutter speeds.
 
Okie
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RE: Intermittent Flashing Red Beacon On Aircraft

Tue Oct 23, 2012 2:35 am

Quoting flood (Reply 8):
If you're recording video at 30 frames per second and with a shutter speed of 1/60 for example (which is generally suited for 29.97 / 30 FPS), your shutter is only open half the time. That said, if the strobe happens to flash during a period when the shutter is closed, it's not captured by the camera.

Some of the early LED's that were adapted to AC circuits (for life expectancy) used half wave rectification. It was possible to record and never see the bulb illuminate on video depending on your timing to when you pushed the record button and frames per second. The human eye would always see it illuminated but it was really not illuminated half the time.

Okie

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