The Amazing Story Of United 811

[joeyb747]

I was looking around YouTube and came across this. It's a five-part series that tells the amazing story of United 811,  Boeing 747-122 (c/n 19875/89, reg N4713U), that lost it's forward cargo door and a large area of forward fuselage while climbing out of Honolulu (PHNL), Hawaii, bound for Auckland (NZAA), New Zealand on 02/24/89. Several rows of occupied seats were sucked out of the aircraft, killing nine passengers. The aircraft lost #3 and #4 engines due to FOD ingestion, and made it back to PHNL on the remaining #1 and #2 engines only with limited flap availability.  

Part 1:


Part 2:
http://www.youtube.com/watch?annotation_id=annotation_190652&v=6pzd9iqZGq8&feature=iv

Part 3:
http://www.youtube.com/watch?annotation_id=annotation_977751&v=CaC6cEBZG1k&feature=iv

Part 4:
http://www.youtube.com/watch?annotation_id=annotation_288780&v=S-jItjR1S2U&feature=iv

Part 5:
http://www.youtube.com/watch?annotation_id=annotation_616358&v=v-N7PW-WjK0&feature=iv

NTSB Probable Cause Report:

http://www.ntsb.gov/ntsb/GenPDF.asp?id=DCA89MA027&rpt=fi

[alltheway]

I have seen this on Discoverychannel before, I really wondered how a crew can determine in flight what it possibly could have been.. They thought of an explosion, but then... not knowing for sure they must have had different scenario's in their minds...  And as it has never occurred again the door locks (due to AC voltage) are better protected now....

Leaves me with another question, are the 747 fuel pumps AC powered? If so when switching them on and off in flight they may rotate the opposite way suddenly... Would be helpfull with fuel imbalance, but only works with a DC powered motor (pump)....

[joeyb747]

The fuel pumps are AC powered.

Two fuel boost pumps are located in each tank. One pump is located forward, and the other is located aft to provide positive fuel pressure at all times. Separate 115V AC buses power pumps in the same tank, failure of any one bus affects only one pump in any given tank.

The APU, however, has a DC fuel pump so it can be started off the aircrafts batteries. This DC pump is located in the #2 main tank. After the battery start is complete, and the APU is running, fuel is supplied by the #2 main tank aft AC pump. The DC pump shuts off after the AC pump takes over. Fuel to the APU can be supplied from any tank except reserves, if needed, through the #2 crossfeed valve.