Date: 20 Jan 98 01:29:32 From: firstname.lastname@example.org (Robert Dorsett) Organization: Netcom Online Communications Services (408-241-9760 login: guest) References: 1 2 Followups: 1
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In article <airliners.1998.39@ohare.Chicago.COM> Colleen M Wabiszewski <email@example.com> writes: >>Pardon me if this is a stupid question, but why do older planes (such as >>a Boeing 707, 727, or 737, and a DC-8 or -9 and MD-80) have an extra >>cockpit window (or two) on top of the main row of cockpit windows? And >>why do newer, but similarly sized planes such as the A320 family and the >>757 have just one row of cockpit windows? > >The extra windows are known as eyebrow windows (perhaps because they >supposedly look like eyebrows on the aircraft from the outside? who >knows where some of these terms come from). In older aircraft they were >used for celestial navigation, before the advent of GPS and other >technological marvels. Several people seem to think this is the reason, but I have my doubts. My admittedly imperfect memory recalls that the 707 and at least some 747s had a periscope that the navigator could attach the sextant to. The navigator would establish a fix and provide steering instructions to the crew. I'd also question the eyebrow for even rough navigation. Seems to me you'd pick a bright star visible in a main window and use that. Also, a lot of these airplanes are really short-range aircraft, which would normally be using alternate navigation methods (i.e., land-based radio or visual aids) to get the job done. My guess is the eyebrows (some of which are very large) are used for see & avoid, originating in an era when flying, rather than managing, the airplane was acknowledged as a primary responsibility of the flight crew. So you'd want to have as good visibility as possible. Modern aircraft probably get rid of them for maintenance or noise reasons. Plus, they tend to have overall better visibility out the main windows when compared to the main windows of older airplanes. Of course, I could be completely wrong. >They are no longer a requirement, although some >newer aircraft still have them for technical or sentimental reasons. We >did a survey here of airline pilots and asked them how they felt about >removing the windows. We expected the response to be positive, as many >pilots stuff the windows with paper to cut down on the glare in the >cockpit. On the whole, however, most respondees said the windows can be >useful in watching out for traffic, they make the cockpit feel more >"open," and, to quote one pilot, "I like to look at the stars." Sounds good to me. :-) -- Robert Dorsett Moderator, sci.aeronautics.simulation firstname.lastname@example.org email@example.com "Bother," said Pooh when his engine quit on take-off.