Base 46 was supposed to fall in a matter of days but rebels have failed to take it after a two-week siege of the Syrian army barracks which is a strategic prize in the battle for Aleppo.
The clashes have dragged on along with the prolonged fighting in the streets of Syria's second city between loyalists of President Bashar al-Assad and rebels.
Causes of the failure to capture the base range from shortage of ammunition among rebels to differences between commanders of various rebel battalions, say sources in the rebel groups.
The rebels had said they mobilised at least 1,500 fighters from across the northern commercial capital and the province of Idlib under the command of General Ahmad al-Fajj to seize the base.
But over the past two weeks, the army has held on to the vast barracks on high ground in Al-Atarib, at a junction of highways connecting Turkey from the west and Idlib from the south.
The troops are firmly entrenched in the building of a former agricultural school in the village of Kafr Ama adjacent to the base, with snipers keeping any advance at bay.
From the base itself the army has regularly fired heavy artillery shells on the surrounding villages of Al-Sahara, Ibizmu and Urma al-Kubra, the last of which rebels say used to be filled with "shabiha" pro-government militias.
Rebels captured Urma al-Kubra on September 22.
MiG fighter bombers, a tiny black dot almost invisible but whose roar reverberates in the sky, have dropped bombs on rebel positions around the base.
Signup to our newsletter and follow us on Facebook and Twitter!
A no man's land of nearly two kilometres (more than a mile) lies near the base where slender buildings are shredded by shrapnel.
"Not a bomb for nearly a week," said a 50-year-old family man sitting on the steps of his house in Al-Atarib, five kilometres west of Base 46. "They fly MiGs from time to time ... They bomb rebels who are close to the base."
The capture of Base 46 would mark a major victory for the rebels, who say they have already "liberated" extensive swathes of territory in northwest Syria stretching from the Turkish border to the gates of Aleppo.
The rebel's takeover of the nearby village of Urma al-Kubra on the highway leading to Aleppo has helped cut the main supply route for the army coming from Idlib.
"The base gets its supplies by helicopters that drop their cargo from very high," said Abu Ali, a bearded rebel fighter with a shaven head. "It often falls to us," he added, laughing. "They are dying of hunger."
The threat of MiGs is seen as the main reason for the army holding on to the base. "And the lack of ammunition among our men," explained a rebel commander, speaking on condition of anonymity.
There are also disagreements between rebel katibas (battalions), say some sources, with some commanders challenging the authority of Fajj, a former officer in Assad's army.
Fajj has banned Islamists, who keep a low profile in Aleppo, from taking part in the siege of the base.
According to the rebel commander, 20 soldiers from the base defected last Friday and gave accounts of low morale and hunger among the 300 to 350 men defending Base 46.
"According to their testimony ... many want to surrender but Alawite officers have threatened to kill them if they make any such move," he said, referring to the minority Shiite sect of which Assad is a member in Sunni-majority Syria.