08/15/2011 at 11:00 AM EDT
's military obligations could take him to Afghanistan
for all of next summer, forcing him to miss two major international events taking place in London – the Queen's Diamond Jubilee and the 2012 Summer Olympics.
Harry, 26, who fought in Afghanistan
in late 2007 into early 2008, could return to the front line as soon as April after qualifying to fly Apache helicopters, according to reports in the British press.
"We need all the Apache helicopter pilots we have, and with our commitments in Libya as well as Afghanistan, none of their applications for leave are set in stone any more," a Ministry of Defense source tells the Mirror.
"The Queen's celebrations and the Olympics are obviously close to Prince Harry's heart, but he knows this is something of an occupational hazard."
Harry will spend some time in Arizona beginning in October for combat training. "This is the final part of the course. Part of the training there makes him combat ready," a source tells PEOPLE. "Then he will have pretty much completed his Apache training," and will be assigned to a squadron.
The question of where or if he is deployed is up to the Ministry of Defense chain of command as it would be for any soldier, the source adds.
And while he would be disappointed to miss the Diamond Jubilee – marking the 60th anniversary of Queen Elizabeth II's ascension to the British throne – he has said she would understand.
"They will be concerned, just as any other family [would be]," Harry said this month. "But my grandmother … she understands more than anybody else that I'm serving my country."
The official Jubilee Weekend is set for June 2-5, while the Olympics will take place July 27 through Aug. 12.