Visible crew/equipment: When Colonel Potter and Charles exit the mess tent carrying the trays, so they can serve breakfast in bed to the winners, they split up and as Charles walks to the Swamp saying, "What a shame to have wasted all these years as a doctor," we have a great view of the boom and boom mic at the left side of the screen as it moves backwards away from Charles, outside the Swamp.
Visible crew/equipment: After Margaret and BJ win the bridge game, just as Charles stands up we can see the top of the Officers Club set, and we see it again when Klinger tells Father Mulcahy, "Everyone bet on either Potter or Winchester."
Visible crew/equipment: After Hawkeye shows the photo of his father to the North Korean, when it cuts to the shot in the Officers Club just as Klinger says, "And these players you can't tell anything," the shadow of the boom mic can be seen moving at the top, right corner of the screen.
Visible crew/equipment: At the start, when BJ calls Hawkeye "twinkle toes" before Hawkeye leaves, the edge of the Swamp set can be seen at the top, left corner of the screen.
Visible crew/equipment: While Hoops Potter is going for the camp record in free throws, in overhead shots with everyone encircling the 'basketball court' - particularly right after free throw 28 and after Potter says that he feels like a sideshow freak, the boom can be seen moving around right beside the hoop's post at the top, left side of the screen.
Visible crew/equipment: While Hawkeye, BJ, and Charles are in the Swamp reading the letters, when BJ says, "Leave it to Charles to be the world's first poison pen-pal," the shadow of the boom mic can be seen moving around at the top right corner of the screen.
Visible crew/equipment: While BJ, Hawkeye, and Charles are in the Swamp, when BJ starts reading the letter from the child who thinks the army is like camping out Charles takes that letter away from BJ, and just as Charles is about to sit back down the edge of the Swamp set can be seen at the top right corner of the screen.
Visible crew/equipment: After Charles confronts Choi Sung Ho about the candy, Ho explains that he sold it on the black market to buy real food, and when Ho reenters the mess tent through the side door, we can see that outside there's a director's chair, which actors also use, with something printed on its back.
Visible crew/equipment: In the overhead exterior shot of the compound, when Colonel Potter calls everyone's attention to the situation regarding "crackerjack corpsman" Sergeant Hutchinson, as the shot pans out we can see the boom and the boom mic at the top left corner of the screen. Then when Margaret calls on Hutchinson to come forward, the boom mic is moving around at the top of the screen, and it's still there when Klinger rides out on Sophie.
Visible crew/equipment: While Hawkeye's helping Klinger with the love letter to Laverne, just as Klinger says, "After all, you're only human, I was thousands of miles..." the boom mic dips into view at the top of the screen.
Visible crew/equipment: After Colonel Potter tells everyone in his office that he's been asked to address them about the possibility of making the army their career, the Swamp trio laugh, and when it cuts to Margaret telling the "clowns" to keep quiet, the shadow of the boom mic bounces around at the top, right side of the screen.
Visible crew/equipment: In the last scenes of the episode, the overhead shots showing the parade where Klinger rides in on Sophie, dressed (undressed) as Lady Godiva, you can see the boom mic in view at the top of the screen.
Visible crew/equipment: When the guy from I Corps Supply lifts the flap at the back of the truck with all the boxes, just as Colonel Potter says, "Sergeant, how many of these parcels are checking into this post," the shadow of the boom mic can be seen at the top, right corner of the screen.
Visible crew/equipment: After Hawkeye shows up in Colonel Potter's office with severe allergy symptoms, BJ and Margaret walk out with him, and when Potter says, "Time we found out what's on his mind," the shadow of the boom mic moves across the door.
Visible crew/equipment: A crew member is visible in Margaret's tent when she confronts OR nurse Helen about her drinking, approximately halfway through the episode.
Answer: It is actually Cencompac for Central Command of the Pacific. It is like the headquarters for all military activity in the Pacific Region (Japan, Korea, Okinawa, etc. The newer version of that is United States Pacific Command (USPACOM).
EMTurbo
And the abbreviations were used mainly by the Navy. Especially CENCOMPAC.
Https://en.wikipedia.org/wiki/United_States_Indo-Pacific_Command.