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A350 29th June 2023 07:53
737 IRS alignment
 
Can anyone provide some information as to why we use the GPS L for initial alignment in the 737? Why not the GPS R?

A350

FlyingStone 29th June 2023 08:08
Boeing’s guidance is to use the most accurate source of position information for IRS alignment.

If your airline prefers GPS L, it is likely because MMR 1 is powered by the AC standby bus, and will likely get a valid GPS fix before MMR 2 (GPS R).

A350 29th June 2023 08:45
Unfortunately our manuals are very light on information on MMR, two lines just.

Thanks for the info.

A350

737pilotguy 30th June 2023 12:56
Originally Posted by FlyingStone (Post 11458779)
Boeing’s guidance is to use the most accurate source of position information for IRS alignment.

If your airline prefers GPS L, it is likely because MMR 1 is powered by the AC standby bus, and will likely get a valid GPS fix before MMR 2 (GPS R).
Correct 👍 No other reason, they're identical in every way except for their power source.


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