Buffalo Airways recently announced, that they’re going to modify their Boeing 737-300SF (C-FBAE), to remove its eyebrow windows and replacing them with black-painted aluminium covers. Let’s dive into the history of Boeing’s eyebrow windows and reasons why it makes sense to have them removed in this day and age.
These small, upward-angled windows, positioned above the main cockpit windows, were once a staple of the 737’s flight deck. While they’ve largely disappeared from newer models, their story sheds light on the evolution of aircraft design—and the disadvantages that ultimately led to their obsolescence.
A Window with a Purpose
Introduced in the original Boeing 737-100 and -200 series in the late 1960s, the eyebrow windows were a carryover from earlier jetliners like the Boeing 707. Their intended purpose was twofold. First, they provided pilots with additional visibility, particularly upward, allowing glimpses of the sky during turns or when navigating celestial bodies—a nod to an era when manual celestial navigation was still a backup skill for long-haul flights. Second, they offered a supplemental view of the aircraft’s wings and engines, which could be useful for spotting ice buildup or mechanical issues in an age before advanced onboard diagnostics.
In the context of the 1960s and ’70s, these windows made sense. Cockpit technology was less sophisticated, and pilots relied more heavily on visual cues. However, as the 737 matured and aviation technology advanced, the eyebrow windows began to reveal their shortcomings.
The Disadvantages Take Flight
While the eyebrow windows served a purpose in their day, their drawbacks became increasingly apparent as the aviation industry progressed. Here’s why Boeing—and airlines—eventually turned away from them:
- Structural Complexity and Weight
Adding extra windows to the cockpit meant additional cuts in the fuselage, weakening the aircraft’s structural integrity unless reinforced. This reinforcement added weight—something airlines, always keen to maximize fuel efficiency, were eager to avoid. On a narrowbody jet like the 737, where every pound counts, the eyebrow windows became a liability. By the time the 737 Classic series (300, 400, and 500) rolled out in the 1980s, Boeing began offering the option to delete them, reducing weight by a modest but meaningful amount. - Maintenance Costs
Each window, no matter how small, is a potential point of failure. The eyebrow windows required their own seals, heating elements (to prevent icing), and regular inspections. Over time, these maintenance demands added up, especially for airlines operating large fleets. Leaks, cracks, or fogging—common issues with aging cockpit windows—could ground an aircraft, driving up operational costs. With no critical function in modern flight, the extra upkeep simply wasn’t worth it. - Obsolescence in the Cockpit
Perhaps the most significant disadvantage was their diminishing utility. By the 1980s, advancements in avionics rendered the eyebrow windows largely redundant. Weather radar, inertial navigation systems, and later GPS eliminated the need for celestial navigation. Meanwhile, wing and engine monitoring shifted to sensors and cameras, providing pilots with detailed data without requiring a peek outside. In the tight confines of the 737 cockpit, the extra visibility offered by the eyebrow windows became a relic of a bygone era, overshadowed by screens and instrumentation. - Cockpit Ergonomics and Distraction
Pilots have mixed feelings about the eyebrow windows. Some appreciated the extra light they let into the cockpit, brightening long flights. Others, however, found them a distraction. The additional visual input could draw attention away from the primary flight instruments, especially during critical phases like takeoff and landing. In an increasingly automated cockpit, where focus on standardized procedures is paramount, the windows were seen as more hindrance than help.
The End of an Era
Boeing began phasing out the eyebrow windows with the 737 Classic series, making them optional for operators. By the time the 737 NG debuted in the late 1990s, they were gone entirely, replaced by a streamlined cockpit design. The 737 MAX, the latest iteration, continues this trend, with a flight deck optimized for efficiency and simplicity.
Airlines welcomed the change. Southwest Airlines, a major 737 operator, famously requested their removal early on, citing cost savings and reduced maintenance headaches. Other carriers followed suit, and today, spotting a 737 with eyebrow windows is a rare treat, reserved for vintage models still flying in remote corners of the world.
The Boeing 737 eyebrow windows are a fascinating footnote in aviation history—a vestige of a time when pilots leaned on their eyes as much as their instruments. Yet their disadvantages—added weight, maintenance burdens, and obsolescence in the face of technology—sealed their fate. For modern aviators, they’re a curiosity, a reminder of how far the industry has come.
Photo (c) Mikey McBryan / Buffalo Airways
