Question for you, Mr. Chuks. Or anyone with Africa experience. Being out of coms (HF and VHF) for such a long portion of your flight, and had your filed flight plan included a climb to FL 370 at some waypoint in a FIR, would you have done so without atc clearance, and if so would it have been at that waypoint? Or remained at last assigned altitude, and perhaps requested the altitude change some time later when coms established? Just trying to understand icao procedures, if anyone at PPRUNE has some thoughts.