jetplaner
Posts: 125
Joined: Fri Mar 21, 2008 3:13 am

Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 2:59 am

Just a question that was bugging me, why do some aircraft have eyebrows. I know that they were common on older aircraft, but they aren't on any new aircraft. That must mean they aren't necessary, so why were they on older aircraft? Would it be for navigation? I know that some 717 have them and some not, and that on later aircraft they were removed to save weight. So why were eyebrows so popular on older aircraft?


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doug_or
Posts: 3118
Joined: Sat Mar 18, 2000 9:55 am

RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 3:12 am

It prevents dust from getting in their eyes and helps them express emotions
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ThirtyEcho
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Joined: Tue Jan 01, 2002 1:21 am

RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 4:55 am

The 737 eyebrow windows are there so that WN pilots can see the end of the runway on a base-to-final turn.
 
KELPkid
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RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 5:17 am

IIRC, the CAR's of old (predecessor to the FAR's) required a certain field of view for the captain and first officer, including the ability to be able to get a good visual scan upwards...

However, you will notice that, in reality, flight crews tend to stick whatever they can into the eyebrow windows to prevent excessive amounts of sunlight from permeating the cockpit  Wink
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GST
Posts: 808
Joined: Wed Jun 11, 2008 10:27 am

RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 7:58 am



Quoting KELPkid (Reply 3):
IIRC, the CAR's of old (predecessor to the FAR's) required a certain field of view for the captain and first officer, including the ability to be able to get a good visual scan upwards...

It is still considered "ideal" for an aircraft to offer 40 degrees of vision above the horizon when the captain is looking between 85 and 95 degrees left, or the first officer the same right. In some cases eyebrow windows were considered the optimum way of offering that field of view, given that a few larger window assemblies can be heavier than several small window assembloes as flight deck windows must resist birdstrike.
 
soon7x7
Posts: 2267
Joined: Thu May 04, 2006 10:51 am

RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 8:23 pm

It's designed to be same scale as a canadian goose, when the windows go dark in flight...expect double flame outs...  Wow!
 
PGNCS
Posts: 2249
Joined: Sun Apr 15, 2007 5:07 am

RE: Why 'eyebrows' On Aircraft?

Fri Apr 17, 2009 9:52 pm

Perhaps one of the certification gurus can comment, but my understanding is that they were put there to meet cross-cockpit visibility requirements at the MDA on a circling approach. They have (obviously) been found to not be needed, so they can be removed on some types now.

I detest them; they do effectively nothing for visibility, but make for much hotter cockpits, and are difficult to shade when the sun is peering through them at just the wrong angle...which leads to a lot of improvised shades normally made from some type of paper easily found in the cockpit.
 
vikkyvik
Posts: 11755
Joined: Thu Jul 31, 2003 1:58 pm

RE: Why 'eyebrows' On Aircraft?

Sat Apr 18, 2009 2:39 am

If you scroll down to page 15 of the following document (page 19 of the PDF), there's a diagram of the Mil Spec for bomber/transport aircraft cockpit visibility (for 2-person cockpits).

I don't know if this is what the FAA uses as well, but it's what I'm (somewhat) familiar with.

www.everyspec.com/MIL-STD/MIL-STD+(0...load.php?spec=MIL_STD_850B.948.pdf
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