Why Did This Boeing 747 Fly With Five Engines?

In January 2016 a Qantas Boeing 747-400 landed in Perth with five engine pods under its wings. Only four of them worked. This is why it flew that way, and what an engine that produces no thrust still costs the airplane carrying it. The fifth engine was a spare Rolls-Royce RB211, switched off and carried under the left wing, between the fuselage and the inboard engine. Another Qantas 747 was stranded in Johannesburg with a failed engine, and Qantas chose to send the replacement on the wing of its regular QF63 passenger flight instead of by ship or chartered freighter. The film follows the operation from the engine's arrival at midnight in Sydney to the delivery in Johannesburg: the designed spare-engine strut and its colour-coded bolts, why the fan blades come off and the core is faired over, and the three costs of carrying it: weight that displaced fuel, drag that cost speed, and a load on one side handled with trim. Together they forced an unscheduled refuelling stop in Perth. Along the way: the fifth pod's origins on the Douglas DC-8 and Boeing 707 in 1959–61, Boeing's 1969 order of spare-engine pods for the 747, the 1970 certification flights, early 747 handling and speed limits from the British certification test pilot D. P. Davies, the FAA type certificate's life limits on wing parts when an RB211 rides as a spare, and Qantas's earlier pod flights in 2010 and 2011. Speed and fuel figures for the 747-400 carrying a spare were not published; the early-747 figures in the film are labelled as such. The failed engine's return to Sydney by sea is described as Qantas planned it in January 2016; we found no record of the voyage. #Boeing747 #Qantas #aviation