mandag 8. oktober 2018

Maintenance - En 5. motor på B747? - Yep, Qantas gjorde det


How Qantas Ferried an Engine on the Wing of a 747

When Qantas 747 VH-OJU had engine trouble in Johannesburg, VH-OJS came to the rescue ferrying a spare Rolls Royce engine from Sydney to Johannesburg for the stricken plane. We wanted to find out more, so we talked with Qantas about how they go about carrying an extra engine across the ocean.
After considering its options for sending a new engine to Johannesburg, including shipping it by sea or chartering a large cargo aircraft, Qantas decided that using the “Fifth Pod” option available on its Boeing 747 was the most efficient way to get VH-OJU back in service. The fifth pod option is restricted to Qantas’ Rolls-Royce-powered 747s, of which they have four (VH-OJM-OJS-OJT-OJU).
Qantas has used the Boeing 747’s ability to ferry an extra engine in the past, most recently in 2011. Qantas used the method often with their Boeing 707s when engines were less reliable, but the procedure has become quite rare.
A Qantas 747 carrying the "Fifth Pod" in 2010.
A Qantas 747 carrying the “Fifth Pod” in 2010.

Attaching the Engine

To prepare an engine for the fifth pod, Qantas removes the fan blades from the engine and installs a fairing over the engine core. They also install an additional fairing over the front of the engine cowling to further reduce drag.
On the "Fifth Pod" engine, the fan blades are removed and fairings added to reduce drag.
On the “Fifth Pod” engine, the fan blades are removed and fairings added to reduce drag.
After the engine has been configured, it takes about 3 hours to install the strut which supports the engine on the aircraft’s wing and the engine itself. Qantas says it takes less time for the engine to be removed from the aircraft. The engine and strut are attached to anchor points on the underside of the left wing, inboard of the operating engines.
The fully installed "Fifth Pod"
The fully installed “Fifth Pod”

Flying with Five Engines

Qantas pilots say that a 747 flying with the fifth pod doesn’t really handle differently than a normally configured 747, but that special flight configurations, such as trim, are used to keep the aircraft flying straight and level. Because of the added weight from the extra engine (about six tonnes) less fuel is added to the aircraft to ensure it is below its maximum takeoff weight. Since there is less fuel on board and the fifth engine adds drag, a fuel stop on a flight such as Sydney-Joahannesburg is necessary.
QF63 first flew to Perth to refuel before departing for Johannesburg.
QF63 first flew to Perth to refuel before departing for Johannesburg.
VH-OJS flew from Sydney to Perth to refuel before continuing on to Johannesburg. Qantas also tells us that the fifth pod means that the aircraft must fly at a slightly slower speed.
After refueling, QF63 continued on to Johannesburg.
After refueling, QF63 continued on to Johannesburg.

Passengers flying aboard Qantas flight QF63, which ferried the spare engine to Johannesburg, were informed of the special nature of their flight the night prior or at airport check-in. Announcements were also made on board. Aviation journalist John Walton just happened to be on an air-side tour of Perth Airport and filmed the takeoff to Johannesburg.


The disabled engine in Johannesburg will make its way back to Sydney at a much slower pace by ship.

Behind the Scenes Film

Qantas put together a short film with some great footage of the engine being attached, we think it’s worth a watch.

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