Originally Posted by
Juud
At the time there was talk here on PPRuNe about it just having come out of maintenance (somewhere in the FE?) and a drip shield not having been installed back where it should have been in the below decks area between doors 1L and 1R. And or it having been cracked.
Hence the drastic effects.
Any word on that in this final report?
There was also talk of 'lazy FAs' having caused a blockage of the galley drain by pouring coffee grounds down it.
Drain mast heater failure is a very different beast.
Just read through the report, and I would say "all of the above".
Drain mast heater failure leading to ice blocking at altitude.
Possibly assissted by ye olde coffee grounds which were indeed down the drain...
Liquid backs up to level of galley floor
Where it leaks out through damaged drains (some damaged by impact from the cart...)
It then leaks through inadequately sealed galley floor
Through bad joints and cracks around fasteners in the drip tray
And finally onto, and into, the unsealed GCUs which are redundant but all nicely located under the same drip...
Three GCUs had corrosion damage, and failed, but
all four had evidence of liquid ingress. I'm not sure on first reading why the three GCUs failed at the same time from what was a chronic liquid / corrosion problem - maybe one tripped and then the others failed trying to switch the additional load.
At the pointy end, neither the QRH or the cockpit displays gave the crew any indication of battery time remaining, and the fact that they werew on battery was only a low priority message anyway
The crew gave up going through the messages and checklists and elected to just continue with landing (ok, good idea with hindsight). They elected not to inform ATC...
On the ground, they taxied to stand as normal, ground power was connected to the failed electrics (is it just me, or ummm...?), and
then found they had no evac ability as pressurisation systems failed and cabin was overpressure.
The cracked drip tray turns out to be another aircraft - the drip trays were checked across the fleet:
The high proportion (52 out of 69) of damaged dripshields or gutters in the
operator‘s 747-400 fleet of aircraft indicates that the issue was widespread, even
though that particular problem could have been readily identified by a visual
inspection during regular maintenance activities
Ouch. Bit of a struggle to blame this one on RR
