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Old 1st Apr 2017, 08:34
  #176 (permalink)  
Join Date: Jun 2011
Location: SW Scotland
Posts: 65
Originally Posted by justanotherflyer View Post

MSA often gets discussed in incidents such as this.... It is a height at or above which, if you are forced to descend to it by deteriorating cloud base or visibility, then you MUST divert or return to better conditions.
Which is, even by the standard of PPRuNe, potentially misleading.

The Minimum Sector Altitude (MSA) is the lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft) above all objects located in the area contained within a sector of a circle of 46 km (25 NM) radius centred on a radio aid to navigation.

As such, MSA is about as relevant to contact flying in remote mountain areas as the rest of the information on a Dutch instrument approach chart.

If confusing MSA with the "minimum safe altitude" as defined, for instance, by 14 CFR 19.119 or the British rules of the air, that's a statutory requirement to maintain 500 ft separation from any person, vessel, vehicle or structure in remote areas.
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