The statistics based on what?
The thing about statistics is that they can be used to paint whatever picture one wants.
Number of fatal crashes per thousand hours flown? Per miles flown. Per ton of cargo moved? In what way is the safety record of the 747 quantified?
If 747's are moving more cargo than other types, might it stand to reason that from a statistical point of view, one might expect a higher number of 747 mishaps...even if the actual rate were the same as other aircraft?
Yes, you could find more, such as Tradewinds out of Bogota, etc. However, in many of those cases, the fact that the airplane was on a cargo mission wasn't particularly relevant. A pilot who rejects a takeoff and overruns, for example, could just as easily have done it in any aircraft...what's behind the flight deck isn't really germain to the statistics or the mishap itself. Likewise, the biggest single loss of life in an aircraft mishap, at Tenneriffe, involved two 747's. Could one say this represents an unsafe aircraft, or could it have happened to any type aircraft?
A cargo company operates only 747's...and experiences one, then another mishap. Does this mean the cargo company is operating a dangerous aircraft because the only type in the fleet that's experienced a mishap is the 747...or does it mean that any other type would be statistically unlikely or impossible, because at that company, it's the only kid on the block?
I don't know that viewing the various unrelated mishaps that have occured in cargo ops with the 747 really point in any meaningful way to an unsafe airplane, or an unsafe combination of airplane and mission. Such is the hazard of statistics.