but perhaps most importantly - starting up the airfield generators.
Good 'ole CAP 168 requires a 1-second changeover but there's another way, which we employ at LGW.
We've created a ring main around the aerodrome that feeds the various sub-stations. We also have 2 x 33kvA inlets from different parts of the National Grid, feeding the ring. This is considered sufficiently robust by the CAA that we don't need to fire up the gennies when we start LVPs, providing it's all in place. If there's a break in the ring, then we have to be prepared to start the generators if we want to go into LVPs.
Here's another puzzle for you. When we're Northern Runway, we're purely visual approach off a SRA, terminating at 2 miles. So why do we have LVPs for Northern Runway ops? There's no ILS to protect and only minimal lighting, side lights only on the runway. It's because some companies can depart in 200m IRVR. We can still derive IRVR using a mixture of the transmissometers and Northern Runway side lighting intensity. We provide safeguarding to ensure no physical intrusion is made into the Northern Runway Cleared & Graded Area under such conditions.
Complicated, isn't it?
Cheers,
The Odd One