Modified base
 

Heard the expression "Modified base" used recently on the radio. Can someone explain please?
DO

Anything that's not a "standard" base?

Depending on the airfield layout and surrounding terrain/noise sensive areas, some airfields may have modified circuit procedures to be used preferentially, with a "standard" circuit being flown only if circumstances require it.

Last weekend I was at EHMZ, an uncontrolled field with a camping directly under the approach 09. So you fly a final approach that's offset by 30 degrees until you're past the campsite. Your modified base may have been a similar thing.

If you tell us what frequency/airfield this was we might be able to tell you more.

Local procedures? I know of places in the USA that use a "modified base" (John Wayne Santa Ana for ex..) because they have parallel runways and don't want someone overshooting into the path of a 757 landing on the parallel. In this instance your base is at about 45 deg I think...

Thanks guys. It was in fact in the USA.
DO