Beginning in August 1915, the 1st Aero Squadron spent four months at Fort Sill, Oklahoma, training at the Field Artillery School with eight newly delivered Curtiss JN-2s. After a fatal crash on 12 August, the pilots of the squadron met with squadron commander Foulois and declared the JN-2 unsafe because of low power, shoddy construction, lack of stability, and overly sensitive rudders. Foulois and Milling, now also a captain, disagreed and the JN-2 remained operational until a second crashed on 5 September. The aircraft were grounded until 14 October, when conversions of the JN-2s to the newer JN-3 began, two copies of which the squadron received in early September.