The route was disrupted in late April 1941 due to an uprising in Iraq which meant that the stop at Lake Habbaniyah was not available and there were no flights between Cairo and Basra in early May. A non-stop shuttle service was then set up between Tiberias and Basra, but the mail capacity was greatly reduced as more fuel had to be carried. The frequency of the service between Basra and Singapore was also reduced to once per week. The associated campaign in Syria meant that it was late July 1941 before the route was functioning normally again.