OXY Points

[Warmtoast]

A friend of mine, much into MS Flight Simulator has some BA charts and asked my advice.

The Central Asia Flight Progress Chart has listed on it two "OXY Points (Oxygen Points)", Oxy1 and Oxy2 as shown below. What do these mean?

Second query, which is mine, is what is the significance of the large numerals shown on the chart - 25.3, 23.3, 21.0, 19.8 etc?

TIA

http://i145.photobucket.com/albums/r231/thawes/Image1-6.jpg

[wiggy]

The chart covers a standard route that goes over extensive high ground ( Western China, North of Tibet). The numerals are an indicator of the Minimum Altitude it is safe to fly at due to the terrain, e.g. 268 means 26800 feet..which, BTW, should give you 2000' clearance from the Cumulogranitus :eek::eek:

If you have a Cabin depressurisation over such terrain you are not going to be able to rush down to thicker air, you are commited to flying for a while at highish altitudes with the passengers breathing the bottled Oxygen from the aircraft tanks. That supply is very, very finite so you need to know wether you have to turn back toward the lower ground and then land at somewhere like Urumqi or continue onwards towards the lower ground and then divert to Beijing or go onto Hong Kong.....the Oxy points define those "decision points". The older charts used to have a full explanation on the back but it looks like your mate has got one of the new charts and the Oxy point procedures are now contained in one of the aircraft manuals.

[Warmtoast]

Thanks Wiggy.
All is now clear and I'll let my FS friend know (and I've learnt something new too).