CWT Scav
Earlier B747 series aircraft had the single AC powered scavenge pump feeding No.2 tank. This was a problem if pump failed or filters blocked with approx 1.5 ton of unuseable fuel remaining.
Later production aircraft were fitted with hydro mech jet pumps feeding both the No.2 and 3 tanks which also reduced the possiblity of fuel imbalance and any unuseable fuel remaining, compared to the single scav pump system.
TW
Last edited by Tinwacker; 25th Nov 2009 at 11:18.