Re: Regional Pressures
There seems to be a lack of understanding as to why we use QFE and RPS in the UK. A couple of reasons for each immediately spring to my mind: safety and simplicity.
QFE: It is used only close to an airfield, not for en-route navigation. To do that would be dangerous. Using it enables me to remember the Decision Height for every single airfield in the country. It is always the same, no matter what the airfield's elevation is, impossible to confuse. Simple and safe. Heights and altitudes of obstructions are listed on airport plates. However, nothing compels you to use QFE. But to use QFE you need a low-lying area, like the UK. Trying to use it at places like Nairobi is a waste of time.
RPS: If you are flying across country, away from other airfields, remaining below the transition altitude, what other pressure are you going to use? The last airfield QNH? What if you fly into a depression, how do you know your safety altitude? If you set the RPS you can guarantee knowing it. Once set, it does not change until the next hour - safe and simple.