The Boeing 707-400 was a larger, extended-range version of the 707-300 series. Introduced in 1964, the 707-400 featured a stretched fuselage to accommodate more passengers, making it one of the most capable and versatile variants in the 707 family. This version was designed to meet the increasing demand for high-capacity, long-range jetliners, particularly for transatlantic and transpacific routes.

With the JT3D turbofan engines and extended wings, the 707-400 was able to carry more passengers over greater distances compared to the earlier variants. While it saw limited production, the 707-400 was crucial in Boeing’s development of larger aircraft, providing valuable experience for subsequent wide-body jetliners like the Boeing 747.

Key Specifications (Boeing 707-420 configuration)

• Crew: 3 (Pilot, Co-pilot, Flight Engineer).
• Capacity: Typically 199–219 passengers, depending on configuration.
• Length: 49.70 m (163 ft 1 in).
• Wingspan: 44.42 m (145 ft 9 in).
• Height: 12.93 m (42 ft 5 in).
• Max Takeoff Weight (MTOW): ~155,000 kg (342,000 lb).
• Engines: 4 × Pratt & Whitney JT3D turbofan engines.
• Cruise Speed: Mach 0.80 (~855 km/h or 531 mph).
• Range: ~7,670 km (4,770 mi).
• Ceiling: ~41,000 ft (12,500 m).

Notable Features

• Stretched fuselage provides additional passenger capacity, making it ideal for high-demand routes.
• Powered by JT3D turbofan engines, offering quieter operation and improved fuel efficiency compared to earlier turbojet versions.
• Increased maximum takeoff weight (MTOW), allowing the 707-400 to carry heavier loads and fly longer distances than earlier models.
• The longer fuselage and improved performance made it a popular choice for airlines on both short- and long-haul routes.
• The aircraft was used for passenger and cargo operations, with several variants converted to freighters later in their service life.

Variants

• 707-400 – Standard version with a stretched fuselage, offering higher capacity and greater range than the earlier 707-300 series.
• 707-420 – A variant of the 707-400 with slightly modified systems for enhanced performance.
• 707-400F – Full freighter version, used by cargo operators for transporting goods over long distances.

Operators & Usage

• The 707-400 was primarily used by airlines such as Pan Am and TWA on international routes, where its extended range and increased capacity were highly beneficial.
• Although produced in smaller numbers than the 707-300, the 707-400 was used extensively in both passenger and cargo operations, especially for high-demand routes.
• Many of the 707-400 variants were later converted to freighters, continuing to serve in cargo fleets.
• Military versions of the 707-400, such as the E-3 AWACS, provided early-warning radar and surveillance capabilities to the United States and allied forces.