Aerospace History: The Rear Stairs of 707 and 727
Boeing's aircraft offerings have been a cornerstone of commercial aviation since the 1950s. Among these, the Boeing 707 and the Boeing 727 stand out due to their unique designs and innovative features. One of the notable differences between these two iconic aircraft is the presence of rear stairs in the 727. Let's explore the history and implications of this particular feature.
Boeing 727: A Tailored Design
The Boeing 727 was designed with a revolutionary feature: rear stairs. Unlike its predecessor, the Boeing 707, the 727 featured an innovative design that included airstairs directly under the tail of the aircraft. This allowed for convenient passenger boarding and deplaning, especially in smaller airports that lacked dedicated jet bridges. The rear stairs were a game-changer, providing a flexible solution for different types of airports and operations.
The 707 and the Early Airline Operations
The Boeing 707, on the other hand, was designed as a long-range transport. It was primarily intended for use at airports equipped with truck-mounted airstairs, which could assist with loading and unloading passengers. The 707's primary function was to fly long distances, and thus it did not require the additional complexity of rear stairs.
Other Aircraft with Rear Stairs
The unique feature of rear stairs was not exclusive to the Boeing 727. Similarly, the Sud Aviation Caravelle, along with the DC-9 series and the British Aircraft Corporation (BAC) 1-11, also incorporated this design. These aircraft shared the innovation of using rear airstairs, which became a common feature in commercial aviation during the 1960s and 1970s.
The Importance of Rear Stairs in the 727
The 727's rear stairs were more than just an additional convenience feature. They played a crucial role in operational safety. Due to the aircraft's heavy weight from its three engines and low fuel load, the rear stairs acted as a tailstand when lowered. This was particularly important during unloading to maintain the center of gravity at a safe position, preventing any unwanted movement of the aircraft.
The In-flight Dilemma: Flight Risk
Despite their intended purpose, the rear stairs in the 727 had a rather unexpected use during flights. The stairs, which were typically lowered while the aircraft was parked, could accidentally deploy while in flight, posing a significant risk to the aircraft's stability and safety. Interestingly, there were reports suggesting that the rear stairs were used by Evergreen Aviation to discreetly place Special Forces personnel on Central American missions. However, the 727's notorious passenger Jerry "D.B." Cooper used the stairs for his infamous exit during a flight over Washington in 1971.
As a safety measure, a small tab was later added to these rear stairs on most 727s to prevent them from opening while in flight. Yet, historically, Evergreen Aviation's 727s continued to operate without this modification, maintaining the original design for its unique capabilities.
Boeing's innovation in incorporating rear stairs onto the 727 revolutionized commercial aviation. These stairs not only enhanced operational flexibility but also underscored the importance of considering diverse airport conditions in aircraft design. The Boeing 727 and its rear airstairs remain significant in the history of aviation, showcasing the ingenuity and adaptability of the aircraft industry.