I wonder at what point repairs would be satisfactory for engineers to declare it usable again. Would it need to go on an empty test flight exactly along its normal path to be declared “safe enough?” What’s the minimum incurred damage at which a plane would be considered totaled?
There are ways to non-destructively test for cracks and voids in various structural elements. Planes already go through very stringent inspection and maintenance cycles so various physical factors will already have a well-established baseline to compare to.
Some speculation; the damage may be far less than you’d think. Aircraft are (generally) designed to fail gracefully and the front landing gear is a mechanism that sees a lot of force during landing. I can’t tell if the assembly folds back into the landing gear bay or if it penetrates the fuselage without collapsing.
A whole sack of shit went wrong if the fuselage fell directly onto the gear assembly but if the landing gear “simply” folded back into the bay it could be a relatively easy repair. Airframe loading is extremely well-characterized and engineers are already running the numbers on what forces went where.
All that said; fuck McDonnell-Douglas. Boeing “acquired” them back in the 90s. Somehow the MDD board of directors (comprised of businessmen) took over leadership roles formerly held by people with engineering backgrounds. A lot of the failures and poor reputation Boeing has suffered in the past few decades are very likely related to that leadership change.
Judging from pictures it does appear to retract forward. Makes sense to me considering the forces the landing gear would experience. If the hydraulic deployment mechanism were to fail midair you can still manually deploy it from the cockpit and it will fall and lock into place.
Would it need to go on an empty test flight exactly along its normal path to be declared “safe enough?”
I’m no expert, but as I understand it a damaged plane has to undergo very extensive inspection and testing of anything that could potentially be damaged before flying again. A single test flight says very little about safety, other than that it happened to work once, and would not be anywhere close to sufficient by itself.
“totaled” has a technical definition: it’s assessed more expensive to repair than to replace. That will include the cost of all the testing.
I have no idea what this will have damaged. Aircraft can be put back into service after some pretty serious damage, but you make a good point that tests on the structure of an aircraft are done on a new one, so you can’t just do a single test and job done to get the same level of confidence that everything’s ok - if something were weakened, it wouldn’t be clear when it might fail.
I wonder at what point repairs would be satisfactory for engineers to declare it usable again. Would it need to go on an empty test flight exactly along its normal path to be declared “safe enough?” What’s the minimum incurred damage at which a plane would be considered totaled?
There are ways to non-destructively test for cracks and voids in various structural elements. Planes already go through very stringent inspection and maintenance cycles so various physical factors will already have a well-established baseline to compare to.
Some speculation; the damage may be far less than you’d think. Aircraft are (generally) designed to fail gracefully and the front landing gear is a mechanism that sees a lot of force during landing. I can’t tell if the assembly folds back into the landing gear bay or if it penetrates the fuselage without collapsing.
A whole sack of shit went wrong if the fuselage fell directly onto the gear assembly but if the landing gear “simply” folded back into the bay it could be a relatively easy repair. Airframe loading is extremely well-characterized and engineers are already running the numbers on what forces went where.
All that said; fuck McDonnell-Douglas. Boeing “acquired” them back in the 90s. Somehow the MDD board of directors (comprised of businessmen) took over leadership roles formerly held by people with engineering backgrounds. A lot of the failures and poor reputation Boeing has suffered in the past few decades are very likely related to that leadership change.
It sure looks like the nose gear rolled forward as the fuselage falls. Which direction does it fold up, wheels fore or aft?
Judging from pictures it does appear to retract forward. Makes sense to me considering the forces the landing gear would experience. If the hydraulic deployment mechanism were to fail midair you can still manually deploy it from the cockpit and it will fall and lock into place.
Hmm, yeah, that makes sense because if it folded backwards, well, if the plane were landing with more force than expected…!
I’m no expert, but as I understand it a damaged plane has to undergo very extensive inspection and testing of anything that could potentially be damaged before flying again. A single test flight says very little about safety, other than that it happened to work once, and would not be anywhere close to sufficient by itself.
“totaled” has a technical definition: it’s assessed more expensive to repair than to replace. That will include the cost of all the testing.
I have no idea what this will have damaged. Aircraft can be put back into service after some pretty serious damage, but you make a good point that tests on the structure of an aircraft are done on a new one, so you can’t just do a single test and job done to get the same level of confidence that everything’s ok - if something were weakened, it wouldn’t be clear when it might fail.