Alternate Landing Gear B-747-400
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Join Date: Apr 2003
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Alternate Landing Gear B-747-400
I have a question on the B747-400 aircraft. I was teaching pilots aircraft systems and had a concern on loss of hydraulic system 1 or 4. On the classic 747 with with only one system loss, when extending the gear alternately the book says to extend the affected gear first then extend the non effective gear normally. Some pilots on the 400 were taught that both gears need to be extended alternately even with only single system loss. Others say that only the affected should be manually extended first. The QRH is very vegue.
Looking at my QRH there’s one section for both systems 1 and 4 inop, one section for 2 and 3 inop, and one section for all other system failure conditions. Both the systems 1 and 4 inop and the all other failure conditions say use to both the ALTN NOSE/BODY and WING GEAR EXTEND switches. The only difference is if it’s both systems 1 and 4 inop it says the action is not reversible, if it’s just one of those systems it says the action is not reversible for the affected system.