Seeing a 747 with 5 engines reminds me of seeing GE&#x27;s N747GE testbed aircraft in Mojave, which usually flew with a odd engine configurations. I can&#x27;t remember if they used the 5th pylon at all and most pictures show an experimental engine on the inboard pylon. Sometimes a very large engine[1], sometimes a small one[2].<p>One time they tried to ferry the aircraft from Mojave to Victorville with only three engines (they must have removed the experimental engine for whatever reason). They attempted the take-off but had to abort. It was quite a sight anyways. They went back to the hangar and we saw it fly away with four engines a few days later.<p>GE now has a second 747 to play with.[3]<p>[1] <a href="http:&#x2F;&#x2F;www.jetphotos.net&#x2F;photo&#x2F;45634" rel="nofollow">http:&#x2F;&#x2F;www.jetphotos.net&#x2F;photo&#x2F;45634</a><p>[2] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;File:Ge-747-N747GE-020404-01.jpg" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;File:Ge-747-N747GE-020404-01.j...</a><p>[3] <a href="http:&#x2F;&#x2F;www.sieinc.com&#x2F;into-thin-air-the-lofty-side-of-jet-engine-testing&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.sieinc.com&#x2F;into-thin-air-the-lofty-side-of-jet-en...</a>