What the hell was that?

THERE IS AND WAS no memory OF ANYTHING, THERE JUST SIMPLY WAS NO HULL BREACH AT THAT ALTITUDE, HOW DID IT BREACH TOUCHI8NG NOTHING? IT WAS PURE AND SIMPLY A XENOMORPH AND YOU COULD TELL CLEAR AS FRIKKING DAY ANYONE WYO SAYS THEY DID NOT THINK AS MUCH AS THE SHIP MADE IT'S WAY DOWN TO THE PLANET THE FIRST TIME THEY SAW THIS FILM IN THE THEATER IS LYING !!! IT IS AMAZING WHAT PEOPLE DO HERE I WILL TELL YOU, DISTORTING THE FACTS TO SUIT AN ARGUMENT WHEN THERE IS NONE !

Uh, no. It's just stress on the ship. Why have an alien outside that has no relevance to the rest of the film?

THERE ALSO WAS NO PRESSURE ISSUES WITHIN THE SHIP AT ALL DURING IT'S DECENT TO LV-426 AND NONE REPORTED OF EVER OTHER THAN ANY CAUSED BY THE LANDING ITSELF! YA KNOW, YOU'VE HEARD THE SAME BIT FOR 33 + YEARS, YOU CANNOT JUST DECIDE OUT OF THE FRIKKING BLUE...THAT THE SOUND A XENOMORPH MAKES WJHEN IT IS THREATENED IS NOT ALL OF THE SUDDEN THE SOUND A XENOMORPH MAKES WHEN IT IS THREATENED. SERIOUSLY !!!

its called Foreshadowing, fart or not it laid its foundation of suspense...

C' mon guys...It's just mechanical. A very clever observation though! Adds to the entire bio-mechanical mood of the film. Machines making noises lke living creatures. The whole feeling during landing and first contact with LV-426 is certainly eerie. A clever noise to add some adrenaline to the spectaror....was it something alien? what was it what was it? and so on. Certainly no creature voice would be audible whithin this huge spaceship , especially during landing which is supposed to be something extremely stressfull and noisy for the ship, as it has to balance its weight floating against gravity....and Nostromo , travelling half the universe, only to land exactly on the sjs ship or a happy sj (or xeno) running around to see who is landing...but it was a clever addition anyway and a nice observation from Mafetu:)

I tend to go with the one that discovered the fart in Alien. You have to agree he watched it toroughly. And it explains we never got to see whatever bended the SpaceJockey ribcage :s.

Its the landing gear.

Hull Breach.