PPRuNe Forums - View Single Post - High Latitude IRS Alignment

25th June 2003 | 08:30

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QAVION

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High Latitude IRS Alignment

I've read that on your typical Boeing 767/747-400/etc, it's recommended that you leave your IRU's in ALIGN for as long as possible before selecting NAV when departing from an airport in high latitudes. A minimum of 18 minutes is quoted.

Would selecting NAV and not entering PPOS for a similar period of time achieve the same goal, or is PPOS required as soon as possible to achieve the "fine tuning" required for high latitude navigation.

Thanks.
Regards.
Q.