Friends were on the earlier flight and were offered upgraded seats on that flight if they changed... they wanted to get home so didn't accept. Very sad for the loss of life... but fantastic demonstration of the strength of that airframe.
Maybe so, but I've always felt that the cargo-compartment doors should be plug-type doors like the ones in the passenger cabin. That would also have prevented the THY DC-10 disaster in France. The amount of additional space needed for plug-type doors is, IMO, insignificant.
Didn't they change almost all cargo doors to plug-ins after those? Didn't the retrofit a lot of them? Stupid, accident waiting to happen, design. The DC-10 had more problems than the cargo doors.
No, they did not and will not change to plug type doors. Any redesigns that may have occurred were to improve the existing stop-pin/cam lock designs. Besides, IIRC, it was human error or lack of maintenance that caused that door to fail. I don't think you will find another 747 that has had this issue due to design flaw.
The passenger doors in the 777 are not plug-type doors in the true sense. They are drop-down stop-pin design. To open they lift and swing outwards The cargo doors on the 777 have huge rotating cam-locks and pull-in latches. The doors on the 767 are plug-type. They retract into the ceiling of the airplane. (L1011 had this too?)
I know 2 people at United maintenance during that time. There was an in house issue tied to the failure.
uh no. They are true plug type doors. 'plug' has nothing to do with the mechanism or how the door is opened, only with how the door reacts loads (internal pressurization).
Jim, most of us refer to doors that are larger than the opening by virtue of angled framing that prevents the door from opening in the outward direction . AND, under pressurization, is forced into and plugs the opening. On the Boeing airplanes the cams and pins do the same, pulling the door into the opening, sealing it, and locking it. My impression.
USN recovered the 2 halves of the cargo door; it split almost exactly in half lengthwise. One pax (without seat) went into #3. Other 8 (with seats) hit wing and/or tail. The final finding was that the door probably unlatched itself (while showing 'locked' in the cockpit) due to a frayed wiring issue. From wiki: "...The NTSB issued a recommendation for all 747-100's in service at the time to replace their cargo door latching mechanisms with new, redesigned locks. A sub-recommendation suggested replacing all outward-opening doors with inward-opening doors, which cannot open in flight due to the pressure differential. No similar fatality-causing accidents have officially occurred on this aircraft type...." So it was recommended that they replace all doors with inward openers... Do not know if that was ever done. The plane was repaired by Boeing's incredible crew and re-numbered; flew for United for many more years, then to another airline for more.
I understand your definition and how it is used but regard it as a matter semantics. It does not meet the original intent and definition of what a plug-type door was meant to be. The original definition of a true plug-type door, on ANYTHING, is that the door cannot fit through the opening from the inside, period. Without the stop pins on a 777 door it would blow out out through the opening under pressure, therefore demonstrating that it doesn't "plug" anything. .
From what I remember, the cause of the failure was damage to the latch control mechanism by ground crew who attempted to force the latch to lock before it was all the way in place. The control mechanism was sprung into place and secured but the latch or latches didn't lock. I have never heard the frayed wire thing. To me, the door being split in half from upper to lower ends would indicate that some latches did hold and others weren't locked. The DC-10 cargo door failures were design flaws.
Bob, sorry, I meant to say that the door split in half from front to back, not upper to lower. There's a pic on wiki... the split is very close to a straight line. They thought that there might have been a wiring issue as they found an issue on another 747-100 at a later date. (Some think that the DC-10 itself was a design flaw. Rushed into production.)
I guess the rationale for outward opening doors is they can load a container at the door opening, where with a plug door they have to leave empty space for the door to open inward. All about the money.
Correct. An inward opening cargo door would waste a huge space in which cargo could be loaded. I worked on a lot of cargo loading studies and the only inward opening door was in the rear bulk cargo area but all the main cargo doors were opened outward by a powered hinge at the upper end of the door. The DC-10 was intensely studied in our group and it was fraught with design flaws in the opinion of those who studied it. It was designed by out-sourced contracted outfits that did it on the cheap.
NTSB report concluded faulty electrical switch or wiring combined with deficiency in latch design: https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR9202.pdf
I guess Boeing doesn't know what the definition is either, since 35+ yrs ago they were issued a patent relating to an 'outward opening plug door'.
The regulatory requirements changed substantially after this accident, and resulted in re-designs of the Boeing latching and locking system.
Recently I gave a talk at Boeing and I opened with the definition of an engineer as someone who solves a problem that you didn't know you had and then explains it to you in a language that nobody can understand. It got laughs from the engineering audience. I am forever disturbed by the misuse of some words in this business and the first that comes to mind is calling the engine STRUTS "pylons". By function and definition , they are STRUTS, but many engineering people insist on calling them pylons.They are not. Now we have a door that opens away from the opening and it is called a plug door. How can that be? The only correlation that comes to mind is a bottle stopper cork that plugs the opening in the bottle by being forced into place. Is the door in question indeed doing that? We plain folk are not privy to the more sophisticated physics terminology and think in basic terms so perhaps this defines a disparity that can cause a bit of confusion at times.
This incident looks almost 'minor' compared to the Aloha Airlines 243 about a year earlier. Everything above the floor for about 20 feet in 1st class was gone. Open to the sky. Amazing that the plane didn't just fold in half. Only one fatality (stewardess - unbuckled)... she was ejected. We had a friend that was an Aloha Stew, had been on that flight many times. Later one pax said he'd noticed when she was boarding that the skin was cracked around the entry door. Didn't say anything. 737 is a tough plane. This plane was NOT repaired, though.
If I remember correctly, that airplane had recently had the lower skins replaced in the forward fuselage and that was credited with saving it.
We see that all the time. Terms are chosen by editors, not engineers and in patents can be chosen by lawyers. From experience I can tell you they both really like their words, not yours. I recently had one change "electrohydraulic" to "electropnuematic" because it sounded better and I missed it on a proofread. A little knowledge isn't a good thing.
