Beech 1900
Air Traffic Control Fully Certified
Confusion; Situational Awareness
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
I was working the R-Side with 3 sectors combined; one of which was a fixed posting. Frequency congestion caused it to feel busier than it was with different aircraft stepping on each other. The Supervisor decided to split the sector. I gave a BE1900 a pilot's discretion descent from FL220 to 100 from the south landing PGA; which is canned clearance many controllers do. The flight path has the BE1900 flash through another sector and back into our airspace. Recently; the MIA changed from 100 to 106. I'm not sure why this is; but the adjacent MIA in our airspace remained the same; which is below 100. I forgot the MIA raised 600 FT in the airspace and while the sector was being split off; I saw the BE1900 flashing with the terrain. I told the BE1900 to amend altitude and maintain 106. He complied but descended as low as 099 before stopping his decent and climbing back up to 106. I'm not sure why the MIA changed. I was told that it wasn't graphed properly and that to more accurately display the correct MIA they would need to create more MIA's? I remember reading a memo about it but I'm so used to giving that clearance that I forgot the terrain changed in LA's airspace. It would be nice to have more accurate MIA's that reflected the terrain in that area since it has been lowered over the last years I've been working here.
Enroute Controller described a below MIA event failing to note a recent change had raised the MIA by 600 FT.