Have you noticed how planes no longer have eyebrow windows above the cockpit-windows? Here’s why those cockpit eyebrow windows are gone from modern airplanes.
What are the eyebrow windows?
The “extra” windows on top of the “regular” windows (in older airplane-cockpits) are called eyebrow windows.
What’s the purpose of the eyebrow windows?
The purpose of these extra set of windows (the 1960s -1990s) was to allow better visibility in turns, especially in tight turns, during visual approaches to runways. On early Boeings and Mc Donnel Douglas airplanes, you’d always find these eyebrow windows.
The windows also contributed to better visibility outside the cockpit overall, spotting nearby traffic. Visibility during turns has become less important, thanks to modern technology aids.
However, “see and avoid” other aircraft always is still a golden rule.
Before the advent of today’s computers and avionics, the windows were also used to help celestial navigation (navigating by stars).
Other cockpit changes from “the old days” of flying
For example, the DC-8 and B-707 aircraft used to have a Navigator in the cockpit. they also had a Flight Engineer (Second Officer) (systems operator), in addition to the Captain and the First Officer (co-pilot).
By the way, another part of the celestial navigation equipment included a viewing hole in the ceiling of the cockpit for the navigator, such as on the DC-8 aircraft. The navigator would use his sextant to plot the flight course.
Why did the cockpit eyebrow windows disappear?
After the advent of TCAS (Traffic Collision Avoidance System), the windows were gradually phased out.
The TCAS functions as a radar that detects nearby airplanes. If an airplane approaches too close to yours the TCAS will give you cockpit alerts to take the corrective action to avoid a potential collision.
Benefits of discontinuing the extra windows
Discontinuing the windows had several advantages:
A quieter cockpit
B737 pilots truly welcomed a quieter cockpit. The 737 was one of the noisiest cockpits around, even today. This mainly because the new B737s are still based on much of the original 1960’s airframe and other technology!
Reduction of cockpit glare
The windows added to unnecessary glare in the cockpit.
Getting rid of the (slight) extra drag caused by the extra windows improved the fuel economy as well.
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Featured Image: Boeing 727 with eyebrow windows. Photo: CaptainJetson.com.