KLM ultimately elected for 10 of its 747-200s to have a stretched upper deck. //

Last year, KLM retired its last Boeing 747 aircraft. This brought the curtain down on nearly half a century of jumbo jet operations at the Dutch flag carrier. The first variant of the ‘Queen of the skies’ that KLM operated was the 747-200, which initially had the same short upper deck as the original 747-100. However, several examples of KLM’s 747-200s ended up having a stretched upper deck, which would eventually become a standard feature on later 747s. //

The result of this change, Boeing proclaimed, was “a 10% increase in capacity with only a 2% change in operating empty weight.” The stretch was a complex, multi-step procedure that required work on more than just the upper deck crown itself. Indeed, engineers also had to remove the roof behind the original upper deck, and the cab crown. //

Indeed, when the next variant of the family was launched, the 747-300, the stretched upper deck came as standard. Aerotime reports that Boeing claimed, thanks to the aforementioned minimal increase in weight despite the 10% capacity increase, this feature decreased fuel consumption by 5% per seat-mile. All in all, it made sense from a financial point of view.

While the 747-300 sold fairly poorly (81 examples), the stretched upper deck was retained by the 747-400 that followed. This quickly outsold its predecessor (694 examples), thanks to factors like its increased range and two-person glass cockpit. The stretched upper deck’s story came to an end when the 747-8 came into being, with an even longer second floor.