When Hawker-Siddeley upgraded the Trident jet to version 3B they added a few things...5 meters of length, room for 30 passengers, and oh yeah...a fourth engine! (Fourth engine circled in red; intake
The cockpit interior of a Hawker Siddeley HS 121 Trident Stock Photo - Alamy
Hawker Siddeley Trident - Wikipedia
G-AWZK | Hawker Siddeley HS-121 Trident 3B | British European Airways (BEA) | Paul Markman | JetPhotos