was split into two sections by the horizontal stabilizers; the upper portion was fabric-covered while the lower half was metal-skinned. The pilot was protected by a bulletproof windscreen, a forward armor plate and an armored seat back. In addition, he was provided with an ejection seat. The Yak-19 was equipped with four fuel tanks in the fuselage that had a total capacity of of fuel. It was armed with two Nudelman-Suranov NS-23 autocannon, each with 70 rounds. Testing The day after the first prototype was completed, it was trucked to Khodynka Field to begin taxiing trials. On 12 December it caught fire when a defective fuel gasket blew out; the repairs took a fortnight. Immediately before its maiden flight, a pair of experimental 23 mm Shpitalny Sh-3 autocannon replaced the NS-23s. It first flew on 8 January 1947 with Lieutenant Colonel Mikhail Ivanov, at the controls, although he was not the primary test pilot. The Yak-19 was grounded from 2 March to 18 May as it awaited a new engine. On 21 May, the afterburner was tested in flight for the first time. While the fighter was the first Soviet aircraft to be equipped with an afterburner, it was not the first one to use one in flight as the Aircraft 156 had done so over a month earlier. The second prototype first flew on 6 June and was almost identical with the first prototype. Changes included five degrees of dihedral to the horizontal stabilizer, a slightly revised vertical stabilizer and plumbing for a pair of drop tanks underneath the wingtips. This increased the fighter's total fuel load to . During the manufacturer's flight tests, the Yak-19 became the first Soviet aircraft to exceed 900 km/h. Major Sergei Anokhin was the primary test pilot and reported that the aircraft had pleasant and predictable flying characteristics and presented no difficulties for the average pilot. Before the testing was completed, Anokhin led the jets participating in the flypast at Tushino Airfield on 3 August. State acceptance tests began on 17 October, using the second prototype, and finished on 30 January 1948. The group of military test pilots concluded that the afterburner was unreliable and the aircraft was difficult to control in roll. Other complaints were focused on the cockpit; it was deemed was too small and lacked sufficient armor and heating or ventilation. They decided that the Yak-19 could not be recommended