His decision was made on the basis of a liberal interpretation of the authority of CG 1st MAW to take action “in emergencies.” In practice, the arrangement worked out smoothly during this preliminary period, and on 12 November CG Fifth Air Force confirmed his oral agreement with a written directive. Direction of air operations in support of X Corps was exercised by MAG-12 for the 1st MAW from 15 October to 9 November. Night operations did not begin until late in October for lack of runway lights at Wonsan, so that VMF(N)-513 flew daytime missions along with VMF-312. The two carrier-based squadrons conducted flights in a similar manner. Aircraft reported at designated times to specified Tactical Air Control Parties (TACPs) for operations directed by a daily Fifth AF order, some of them in response to previously submitted requests of ground units for air support. Major Vincent J. Gottschalk’s Marine Observation Squadron (VMO)-6 was under the operational control of the 1st Marine Division, though it was under the administrative direction of MAG-12. Two helicopter pilots, Captain Wallace D. Blatt and First Lieutenant Chester C. Ward, flew from Kimpo to Wonsan on 23 October. The rest of the squadron had proceeded by LST. A flight echelon of helicopters, commanded by Captain Victor A. Armstrong, VMO-6 executive officer, remained temporarily at Kimpo at the request of the Fifth Air Force to evacuate casualties of the 187th Airborne RCT in the Sukchon area.[89] [89] 1stMarDiv _SAR_, annex WW (hereafter VMO-6 _SAR_), 2. _MacArthur Orders Advance to Border_ From all that has gone before, it might be expected that UN strategy and tactics, after frequent modification, had finally been decided upon by mid-October 1950. This was not the case, and a brief recapitulation of events in western and central Korea is now necessary in order to set the scene for the sweeping changes that followed. General Walker’s Eighth Army, as mentioned earlier, had deployed along the 38th Parallel after relieving X Corps above Seoul on 7 October. Two days later, armored elements of the 1st Cavalry Division crossed the boundary to spearhead the U. S. I Corps drive on Sariwon and Pyongyang. The former city was secured on 17 October with the help of the 27th Commonwealth Brigade, while the 24th Infantry Division moved up the west coast on the left of the Kaesong-Sariwon-Pyongyang axis.[90] The 1st Cavalry Division continued the attack toward Pyongyang on the 18th, entering the Red capital with the 1st ROK Division the next day. Pyongyang was secured on 21 October, and elements of the 1st Cavalry Division also occupied the undefended port city of Chinnampo, 35 miles to the southwest.[91] [90] EUSAK _WD Sum, Oct 50_, 13–23. [91] _Ibid._, 25–30.