I'm slightly surprised to see that this definition is considered obscure. Perhaps I've been disproportionately exposed to it through my slight obsession with mo

I'm slightly surprised to see that this definition is considered obscure. Perhaps I've been disproportionately exposed to it through my slight obsession with motor-racing :-) Having said that, Boeing's situation is closer to the first definition of 'debt' than you might imagine, if you consider the idea of 'technical debt', a concept that (at least in a software context) most of the HN crowd will be familiar with. The 737 is in a recognisable state of technical debt - if it were a software product, its innards would be written in FORTRAN.