Ross if you put a perm construction in it is counted as a mod and that costs tens of thousands.
There is a story about a FO creating a ramp which the Captain thought was very good apart from the fact it wasn't secured in place. The FO over night took a drill and drilled through the spar and put a threaded rod through and tied the whole lot together very nicely.
Next day showed the Captain who went a bit pale. The airframe was a write off BAe said they had to replace the spar.
And there are 4 general flavours of civilian jetstream 3100 series aircraft apart from cabin fit. remember it was intailly designed to be a military aircraft.
There is the intial run jetstream 31's with a single over wing exit and 920 shp engines
There then is a testing period for the J32 where they try out a few things but apart from being wierd they are in essance a J31. Such as auto relight and Negative torque system. There a bit of PIA to be honest the switches/CB's for quite a few systems are in funny places.
Then you get your Jetstream 32's with 2 over wing exits and 1020 SHP engines and a few other difference which only the cockpit will know about.
And you have the J32 EDAM which is a preformance related thing they stick extra vortex generators on the wing and two big wedges next to the engine as fairings. It allows us to do flap 0 departures and other benefits if its hot.
Now they are quite a fun pilots aircraft apart from landing the sods. Its quite morall destroying when you first start flying them. You think you have cracked it then bang you get dumped onto mother earth with a clatter and grunts from everyone onboard. Even after flying them for years you can't be 100% certain what the landing is going to be like, some that you think are going to be carrier jobs turn out smooth and others that you think are going to be peachy you have to do the walk of shame and apologise to the pax.
But when it comes down to it, its a cracking aircraft in bad conditions. The engines have a good responce to the power lever changes, its quite a responsive aircraft on the controls, and its built like a brick poo house. After landing one in challanging conditions I have to stop myself smiling while letting the punters off. Its not that I think its funny scaring the punters its just that I really enjoy flying them.