The government of China in May 1966, formally protested an incursion by a Republic F-105 Thunderchief pursuing a North Vietnamese MiG it subsequently shot down 25 miles inside Chinese territory. A US board of inquiry recommended that College Eye also had to monitor the "no-fly zone" inside the North Vietnamese border with China, to provide alerts to US aircraft nearing the buffer zone and to report border crossing violations by US aircraft. This could not be done from the Gulf so a third orbit, "Ethan Charlie", was created in Laos. After tests in June and August, regular missions began 24 August. There were not enough EC-121s or crews to support 3 orbits twice daily, so the Laotian orbit was only flown every third day, with Ethan Bravo missions canceled on those days. After 13 October 1966, the Charlie orbit was flown every day and the Bravo orbit suspended altogether. In April 1967, 4 more EC-121s were deployed, 2 to Thailand on 29 May, making for a total strength of 3 College Eyes in Taiwan and 6 in Thailand.