ALTINOZU, Turkey — When helicopter pilot Ahmad Trad decided he wanted to defect from the Syrian air force earlier this year, he realized it wasn’t going to be easy. His Damascus air base was closely monitored, he was sure his phone was tapped and he suspected that one in every three of his colleagues was spying for the government.

He also confronted the dilemma that he and other defectors say is the biggest deterrent to those who would like to abandon the Syrian regime but have not yet dared: the safety of his family. Slipping away from his base was one thing, but it was just as important for Trad, 30, to make sure his relatives would not be targeted for revenge attacks once he was gone.

“I had to get everyone out,” he said as he sat surrounded by many of the 15 family members who fled with him last month to the picturesque town of Altinozu in southern Turkey, including his pregnant wife.

“If you want to defect, you have to plan it really well,” he said. “It is so difficult.”

The family’s escape culminated a five-month odyssey of intrigue, deception and ultimately courage that illuminates both the challenges that faced the tens of thousands of soldiers who have already defected from President Bashar al-Assad’s military — and perhaps some of the reasons why more have not done so.

None of the defections has yet been significant enough to shift the balance of power in Syria’s steadily escalating armed conflict. But they are accelerating, contributing to a gradual erosion of the security forces that could eventually undermine Assad’s hold on power.

They are also starting to touch on the heart of the establishment, with Syria’s ambassador to Iraq abandoning his post last week and a former member of Assad’s inner circle, Brig. Gen. Manaf Tlas, fleeing the week before — a public signal of disaffection within the ranks of the elite Sunnis who have thus far remained loyal to Assad’s minority Alawite regime.

As the regime increasingly relies on combat helicopters to assert control over territories lost to rebel forces, questions too are growing over the loyalty of the air force, whose pilots are mostly Sunni. Trad said he learned of the defections of eight other helicopter pilots from his base within a week of his own, which was followed by the highly publicized flight of a fighter pilot to Jordan in his Russian jet.

“There’s a huge number of pilots I know who want to defect,” said Trad, who is Sunni. “The air force in the beginning was sidelined, but after it started getting involved, a lot of people started thinking about defecting.”

Trad’s account cannot be independently verified because of reporting restrictions in Syria, but he showed cards identifying himself as a member of the military and made one of the videos used by the Free Syrian Army to announce defections on YouTube after he arrived in Turkey.

A deepening unease

He said he began his journey many months ago, with a deepening sense of unease about the harsh tactics being used by the government in its efforts to quell the revolt.