Watching this Video of a L-1011, I noticed an orange/brown object on the back of the jet-engine pylons I never saw before.
- What is it?
- What's the purpose of it?
Manu H is right. It is an IR jammer device. Saudi (corrected from the comment of David Richerby:)Royal Flight airliners tend to have them (root of the wing, next to the light)...
I think this is an infrared counter-measure device, i.e. a device intended to protect aircraft from "heat seeking" missiles. Saudi no doubt flies to some potentially dangerous spots in the Middle East. See this article.