Complicated! You should be a bit more specific as to what you mean, because your question is way to broad. read more
You should be a bit more specific as to what you mean, because your question is way to broad. A Boeing 747 is a huge flying building, with not just propulsion and flight controls, but also many other things - all needs more or less maintenance. read more
787. For example, the 747‑8 and 747‑400 have the same type rating and ground‑ support equipment. Flight handling characteristics of the 747‑8 are also very similar to the 747‑400. Figure 1: 747 model comparison The primary external differences between the 747‑8 and the 747‑400 are in wingspan and fuselage length. read more
More than 50 percent of the 747 Classic fleet and 70 percent of the 747-400 fleet were involved in the three-year effort. The resulting 747 Classic and 747-400 Maintenance Review Board Reports (MRBR), which have been approved by the FAA, can help 747 operators significantly reduce maintenance costs. read more