A Lull in fighting occurred from the 17th of March to the 30th of March. The Viet Minh further tightened the noose around the French central area (formed by the strong points "Huguette", "Dominique", "Claudine", and "Eliane"), effectively cutting off "Isabelle" and its 1,809 personnel to the south. During this lull, the French suffered from a serious crisis of command. "It had become painfully evident to the senior officers within the encircled garrison – and even to Cogny at Hanoi – that de Castries was incompetent to conduct the defense of Dien Bien Phu. Even more critical, after the fall of the northern outposts, he isolated himself in his bunker so that he had, in effect, relinquished his command authority". On 17 March, Cogny attempted to fly into Điện Biên Phủ to take command, but his plane was driven off by anti-aircraft fire. Cogny considered parachuting into the encircled garrison, but his staff talked him out of it.