The Deacon laying eggs?

fun, but unlikely!

Can't be because we clearly see the "ribs" of the pilot's chair close around the Engineer, so the Space Jockey HAS to have been in the seat on the original Derelict when he got bursted. I had a similar theory about the Company changing the designation of LV-223 to 426 so people would not know they had ever been there, but the one hole in it was the Engineer died in the lifeboat. It could still be because that chair obviously let the guy out so it still works..................

"...can only be flown by having an engineer in the pilot seat, ..: For such an advanced race,, the Engineers hAve not displayed any androids to assist in the flying of their ship... On most ships isn't there a back up plan/console to pilot a spaceship? I still don't understand how the SJ is the only Engineer displayed in 'Alien',,on such an important mission

... work of fiction by non-technical personnel, please step away from the technology.

Or me analyzing Scientific jargon when I can hardly turn on the computer!

It seems as though Ridley Scott is suggesting that the Juggernaught as a whole and the pilot Chair are in some ways bio-compatible and seem only to function in that manner. Much like in The Terminator series when Kyle Reece says to the criminal psycologist that the bio-displacement time field is only genertaed by a living organism, nothing dead will go. The same rule may apply to the Juggernaughts in-flight/start-up systems, you need a living, breathing 'host' in some ways if you really think about it. By definition, if you think in terms, the ship functions as much as an incubator for mutual advantage to work adequately enough as the one sitting in the pilots seat in many ways becomes a host to the ship itself. The two become one and are inextricably linked and that is bizzarly what the Space Jockey seems to resemble as much as the Engineer when he boards the pilot chair, they both seem 'fused' in to the seat itself.