>You haven't made comment on Mechanical Man's post on the pressure relief door mechanism? He is absolutely correct you know and if you have a look at your website Figure 4- Boeing lower lobe forwrd cargo door schematic, you will see the mechanical linkage of the pressure relief door torque tube which rotates around the midspan latch torque tube.
JBS>The point about the pressure relief doors is that they don’t blow out when overpressure occurs. They are not designed to blow out for safety in flight or other reasons. They are there to relieve inside pressure when opening the door on the ground so that it does not pop suddenly and injure the ground crew.
And yet the pressure relief doors jam open, are missing, and shattered for five cargo doors on Boeing 747s. That’s ten pressure relief doors in five cargo doors that are found in the wreckage. One would think those small doors would remain in place in some of the large cargo doors.
The pressure relief doors are supposed to open with mechanical linkage when the door is attempting to open. That is supposed to be on the ground but if in the air, one can see that big door fracturing at the midspan latches and the little doors in the door blowing out, jamming, or remain missing, as the evidence shows, as the torque tubes turn. As the midspan latches are the first to rupture open and those latch torque tubes are connected to the pressure relief door torque tubes, there is a non coincidental connection there.
To say the ground handling bus can not supply power to the cargo door is to say when normal things happen we land safely. NTSB refused to blame electrical for United Airlines Flight 811 but instead accused an incompetent ground crew for improperly latching the door.
But, after non expert civilian’s family victims got the Navy and NTSB to retrieve the door pieces over a year later, it was properly latched and the electrical explanation came into play after frayed wires were found. NTSB now accuses switch S2 and/or faulty wiring for getting power to that cargo door to cause it to inadvertently open in flight.
Note that so far, I have not read that the doubler failed, just cracks emanating from it. Would not that stainless steel doubler be shattered and broken if it had failed? Isn't stainless steel stronger than aluminum? If cracks around the doubler failed then the failure was in fuselage with the doubler possibly aiding in that failure.
The cargo door is shattered and broken and has cracks from it also, as ASC states, and yet? Little suspicion. One newspaper article and two aviation magazines and all three point to the ‘poor’ repair by China Airlines on a plane of theirs. Boeing is exonerated, it’s not their fault, sighs of relief all around....except for those who see the match of the actual broken metal that matches other broken metal in planes that had no repair doublers.
Where is Firehorse to give descriptions of wreckage? Where is the press asking for clarification for the conflicting stories about the parts of the aft cargo door that are or were not found or were locked or not locked?
It makes more sense to me that the aft cargo door failed for the same reason it failed for United Airlines Flight 811 since they are identical in function, and then the fuselage cracked around a repair doubler...and less sense for cracks around a repair doubler to fail the integrity of the hull leading to an aft cargo door shattering which matches other cargo door shattering with no repair doublers present.
Need more evidence, as usual.
Barry