In 2016, Qantas needed to get a new replacement engine to Johannesburg, South Africa
on rather short notice. While aircraft parts are often transported on cargo planes,
the Australian carrier took a different approach. In this case, the quickest way
to get the engine there was for it to catch a lift beneath the wing of another Boeing 747.
Let’s take a look at how this unfolded...
This picture depicts a rather unusually-configured Qantas Boeing 747-400. As we can see,
this aircraft has an unbalanced engine layout, with two on one side and three on another.
Of course, in times of extensive research and development into new engine technology,
aircraft having strange engine configurations is not a new phenomenon.
Indeed, both Airbus and Boeing are known to add on a different engine to testbed aircraft.
For example, Boeing tested the new GE9X on a 747 before installing it onto its new 777X. Meanwhile,
Airbus tested the TrentXWB engine for the A350 on the A380. However, it’s quite rare to see an extra
engine on an aircraft, and an odd number at that! So why did Qantas operate a commercial Boeing 747
flight with five engines, and how did the airline manage it?
According to Qantas, a broken Rolls-Royce engine had stranded one of its Boeing 747s
in Johannesburg, South Africa. The Australian flag-carrier had plenty of spare parts back
in Sydney, and thus didn’t need to go to the trouble of sourcing locally. However, to have
shipped a spare engine over to South Africa would have cost time and, subsequently, more money.
After all, having a 747 stuck on the ground abroad, not earning revenue,
is a costly proposition. As such, Qantas could not afford to wait.
A major problem, however, was that the spare powerplant was too big to fit in
the cargo hold of a typical aircraft. While the Antonov An-225 would have had space,
there is only one in the world, making it expensive to hire.
Sending spare parts by sea would have been cheaper, but also extremely time-consuming.
Indeed, this was a catalyst for Boeing’s decision to construct the 747LCF ‘Dreamlifter.’ This
reduced shipping times from Japan to the US from a month to nine hours. Fortunately, Qantas found
a third option. It would simply attach the spare engine to the wing of an existing 747.
Thanks to the design of the 747, there are anchor points under the wing to attach
various objects. One of these can be a spare engine. This engine is not connected to the
aircraft’s systems and would not be able to provide additional power to the jumbo jet.
However, its presence does impact how the plane flies. Flying an extra engine
had the following effects on the aircraft: The aircraft was unbalanced, requiring pilots to
compensate for the skewed weight distribution. The extra engine added drag to one side of the
plane, requiring pilots to adjust the power on the other side to compensate.
Finally, an extra engine meant that the aircraft was heavier and required additional
stops. This particular trip between Sydney and Johannesburg involved a fuel stop in Perth.
Once the aircraft landed in Johannesburg, the fifth engine was detached and installed
on the grounded Boeing 747. Both jets were then able to fly back home to Australia.
As for the broken engine, it was shipped back the slow way to Sydney, by sea.
Did you know about this special trip? Let us know by leaving a comment.