I flew the Friendship for 10 years. It was great, solid and faithful.
The tropical kit is an additional heat exchanger for the aircon system.

Cavortingcheetah - The Tropical kit sounds more like a torture kit - if your the Captain expect daily dosses of heat exhaustion and dehydration or if your still awaiting your chance to shine, constant flu and eventual pneumonia. I expect this instrument of medievil creation was limited to passenger versions only and like most freighters have since been removed along with any other weighty pilot comforter such as A/C and Heating when they ceased to function some time back when Reagan was still President...:eek:

If the red peril in the picture has a cargo door on the port forward fuselage then the presumption is that it's a 600? That is a tropical kit scoop on the rear starboard fuselage. The effect was to pump additional cold air into the cockpit through the nozzle behind and to the right of the FO's seat. The cooling air flow was pretty much restricted to the first officer.
Incidentally, if that cargo door is ever improperly latched in the up position with the cross pole provided and decides to close, you will not jump out of the way in time and you will probably be cut in half.

The aircraft you are talking about is a F27 MK500 converted to cargo with the large cargo door and tropical kit removed because there is no need for pilot comfort!!!

F-27
 

I wonder if the ex Tchadian 600 is the same one that sat on the infield of Ndjamena for about seven years missing an engine before being resurrected by a couple of South African guys and flown out in about 2006/7, saw the same pilot in Ndj shortly after flying a G1, said the ferry of the F27 was a truly frightening experience.

Yesir this is the same F27-600 serial number 10430 Ex Air Tchad which sat in the sun from Dec 97 until Aug 02 in Ddjamena before it was ferried to Rand airport and overhauled by Fields Airmotive before heading north again to DRC where it was operated by Malu Aviation for Transair Cargo flying passengers until being bought by Air Kasai and then eventually to another in Lubumbashi where it met it ultimate demise....I believe the captain in still there flying a G1 amongst other things...:mad: