Earlier quoted context omitted.
Why is this necessary. I take it 747s have been safe up til now?
The reason the FAA considered fuel tank inerting in the first place is because of a 1996 crash of a 747 that killed 230 people[1], and which is thought to have been avoided had the tanks been inert[2]. Other 747s were lost to the same issue, such as the ULF48 that crashed in 1976 killing all aboard[3]. To answer your question, no, the 747 is not "safe". No aircraft ever made is "safe". They will all crash and kill pe…
I'd argue that modern aircraft are safe especially after you factor in how many hours these things fly compared to the number of deaths. Of course, air travel has become significantly safer over time. Check out the early history of 727 hull losses. While the 747 had a number of poor designs (especially early on), the deadliest 747 wrecks were due to pilot error (e.g. Tenerife).