Okay to add fuel to the verbal fire...
Caravan's in this neck of the woods definitely have a problem with bursting tyres. One operator is convinced that Cessna were selling dud left-hand tyres because it was always that side - just before first left - that blew. Some people's normal SOPs are to approach at 600lbs torque, +100kts, fly to the ground for a positive landing, beta, brake and turn off the runway. It makes perfect sense that the left tyre would therefore be suspect - nothing to do with the excessive braking and loads on that side!
And going back to Mail-man.. I'm fascinated that airlines don't have to follow the requirement for alternate fuel. So what does the despatcher put in the alternate and 2nd alternate airports? "Not required"? I've been through the FAR/AIM and all I can find is the phrase (rehashed in various formats) that requires fuel to destination and either 45 minutes to alternate, or 10% of total time from destination to origination, and 30 minutes of holding fuel etc. I can see a sort of warped logic in European/US ops where if the destination is fogged over, you can probably hop next door to somewhere that isn't, but it obviously doesn't apply in the Third World where airports can be a wee while apart - such as Kili to JK.
Lastly, it seems unlikely that loads between Addis & Kili (a well-known busy route?) were at capacity, so with only a mere 725 nm between them, the fuel load can't have been that much in a 767 - with no fuel reserve?
Or was it an official plan to use Arusha as the alternate? Or not?