OROCA

AcronymDefinition
OROCAOff Route Obstruction Clearance Altitude
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References in periodicals archive ?
Oroca recalls life inside his UNIFIL base and the day when villagers from around Qana came asking for protection.
Oroca, who was present at the attack, leaves the memorial, walking away from the speeches and official commemoration.
Per the Instrument Procedures Handbook, OROCAs do not provide acceptable altitudes for terrain and obstruction clearance for RNAV direct flights.
If you're not sure what type of terrain you're flying over, look at AIM Figure 5-6-3 (camouflaged in with the ADIZ boundaries), or you could subtract the Maximum Elevation Figure (MEF) on the sectional from the local Off-Route Obstruction Clearance Altitude (OROCA) and see if you get 2000 feet or 1000 feet.
Once you get to these limits, and you're not on a published route, good preflight research (OROCA anyone?) and excess climb rate are your best allies.
You can also descend to the MEA or OROCA as appropriate.
It's vital to make sure that you at least know the minimum off-route altitude (MORA, also called the Off Route Obstruction Clearance Altitude or OROCA in the U.S.), and how it relates to your performance envelope.
One would do better to follow the rules used in creation of off-route altitudes (OROCA or MORA): for terrain, round up to the next higher 100 feet, add 100 feet for source error, and add 200 feet for possible towers (towers under 200 feet are not required to be reported), then add the 1000 or 2000 feet IFR buffer.
Nor is the OROCA (off-route obstruction clearance altitude)--which you'd be using on a "direct" anywhere near 4000 feet.
The image in the magazine doesn't show all the MEAs and OROCAs (the area in question would be too dense with information at that scale).
Their MEAs are often lower than the sector Off-Route Obstruction Clearance Altitude (OROCA) too, so they can buy you a little more cushion between your wings and the freezing level certain times of the year.
Off-Route Obstruction Clearance Altitudes (OROCAs)--those big numbers in each quadrant of the en route chart--provide this level of obstacle clearance in reference to the highest obstacle in that geographic area plus four miles beyond.