Whenever Tan Kah Han, a lieutenant colonel in the Singapore Air Force, takes off to the north for training in his F-16C jet fighter, he faces an immediate problem: Climbing at 540 kilometers per hour, he has barely 45 seconds to avoid crossing the border with Malaysia, less than three kilometers away.
Taking off to the south from their base at Tengah is not much easier for Colonel Tan and other pilots of F-16s, Singapore's most advanced combat aircraft. In no more than two minutes, they must turn into a narrow corridor that takes them to one of only two relatively extensive training areas available to Southeast Asia's largest and most potent air force.
One, over the Indonesian island of Sumatra, is the result of an agreement with the Indonesian government; the other, over international airspace in the South China Sea, is jointly administered with Malaysia, which in 1998 — in one of a series of disputes between the two countries — alleged that low-flying Singapore military planes were spying and banned them from its airspace.
Officials say that as a small but prosperous island-state in the middle of an increasingly turbulent region, Singapore must maintain a strong defense force. But keeping it well-trained and combat-ready is a constant challenge.
"Our airspace is very small and congested with aircraft because we are a busy civilian aviation hub," said Colonel Tan. "So we have to be very disciplined in sticking to our airspace limits."
Singapore, with a total land area of just 660 square kilometers (264 square miles), has a correspondingly small section of airspace, making it impossible to give air force pilots any extensive training or flying experience within national boundaries. Such factors, combined with erratic tropical weather conditions, are severe constraints.
Largely as a result, at least a quarter of Singapore's force of about 150 planes and helicopters is stationed abroad at any one time, mainly in the United States, France and Australia. Short-term flight training for Singapore military pilots is done in Indonesia, South Africa, Bangladesh, Brunei, New Zealand and Canada.
Faced with competing demands for land for industry, business, housing and recreation in Singapore's thriving economy, the 50,000-strong army and 200,000 reservists also face a space crunch. They, too, have to train and exercise overseas regularly, mainly in Australia, Brunei, Taiwan, Thailand and New Zealand.
The Singapore defense minister, Tony Tan, said during a budget debate in March that the Singapore military "trains regularly in about a dozen countries all over the world."
Analysts say that the costs involved in transporting troops and equipment over long distances, and of paying for foreign training rights, are a significant part of Singapore's annual military spending of about 7.4 billion Singapore dollars ($4.1 billion), or about 5 percent of gross domestic product.
The need to move army and air force components regularly over long distances has been cited by officials as one of the main reasons for the recent acquisition of new military equipment. It includes four locally built, missile-armed naval transports, each displacing 6,000 tons and carrying two helicopters. It also includes delivery of two of four long-range KC-135R tanker and transport aircraft ordered from the United States. These tankers can refuel any of the Singapore Air Force's fighters while they are flying.
Tim Huxley, who directs the Center for South-East Asian Studies at the University of Hull in England, said that Singapore's range of international military links and activities was the most extensive of any Southeast Asian state.
"The Singapore armed forces have benefited not just through access to realistic overseas training, but also from widespread exposure to combat-experienced Western armed forces' operational doctrine," he said. "The extremely close collaboration between the Singapore Air Force and the U.S. armed forces is the most obvious example of this."
Twenty-four of Singapore's 30 F-16C and F16D fighters are on long-term detachment at two U.S. Air Force bases in the United States. Some of Singapore's CH-47 Chinook heavy-lift helicopters and KC-135 tankers are also based in the United States.
To take advantage of better weather and extensive flying space, Singapore several years ago shifted its entire basic jet training unit to the Australian Air Force base at Pearce, near Perth, in Western Australia. Around the same time, it reached a separate agreement with Australia to station 12 of Singapore's Super Puma helicopters for 15-years at the Australian Army's Oakey base, in the state of Queensland.
"Increasingly close defense relations with the United States, Australia, New Zealand, Britain and France have helped to anchor these friendly powers' regional security presence in Singapore, improving the city-state's security by complicating the calculations of likely aggressors," said Mr. Huxley, the author of a recent book on the Singapore military.
Eighteen of Singapore's 50 upgraded A4-SU Super Skyhawk fighter-bombers, along with about 200 Singapore Air Force personnel and 140 family members, are stationed at the Cazaux air base in southwest France. The planes and crew rotate every two years.
The deployment, first agreed to between the French and Singapore governments in 1998, was extended last year to 2018, from 2002. Singapore is the only nonmember of the North Atlantic Treaty Organization that is allowed to undertake long-term military training in France, officials said.
