The Ballonets are there to prevent overpressurisation of the gas bag. As the craft rises and air pressure decreases. you have to dump air FROM the ballonet to stop the main gas bag overinflating. If you pumped more air IN, then you run the risk of the whole thing going "pop" as it rose
Wrong - The ballonets are used to (1) compensate for helium expansion/contraction and thus maintain hull pressure, (which is surprisingly low), (2) trim the airship in flight (3) ballast the airship along with the water and lead shot ballast.
You never run the risk of the whole thing going "pop" because the pilot can balance the helium and air pressures using the valves in the hull skin. Should he try really really hard to "pop" the "gasbag" the valves operate in automatic mode. The same goes for the ballonet fans, the pilot is not allowed to let the hull pressure drop too radically. If the hull pressure drops, the ballonet fans kick in automatically raising the pressure in the ballonets and as a side affect increase the weight which brings the airship and crap pilot slowly back to earth.
The peace process didn't finish NISP - it was a technical fail as it used way more fuel than planned...
Wrong again - The high fuel consumption was known about very early in the project - years before it was deployed operationally. This was a result of all the military modifications that were carried out to an off-the-shelf passenger airship. The armour plating alone ruled out an effective endurance. If it were known that it would ultimately be armour plated, a much bigger "gasbag" would have been used at the build. The Ballykelly "fumes" incident arose from a tasty job generated by the mission equipment.