Thursday, July 16, 2026

260716 The Mode Two Codes

The first event occurred way up north in the Gulf of Tonkin, early in the Vietnam war.

The second story happened on the USS Enterprise.

Early in the Vietnam war the navy was operating way up north while bombing north Vietnam.

The aircrew I was on was way up north providing radar coverage for the Seventh Fleet. I was working the radar scope. The Combat Information Officer was standing just behind me. He was nervous because we were close to Hainan Island. He was afraid the Chinese would launch fighter jets to either shoot us down or force us to land and become prisoners of the Chinese army.

I picked up a contact coming out of the Chinese mainland. It was not something we would normally see and not likely a threat. I asked the Officer if I should report the contact. He thought for a minute and then said to report the contact.

The control ship for the entire area was called Alpha Whiskey. Our plane was called Victor.
The report went like this: Alpha Whiskey, this is Victor, bogey, 040, 170 miles, course 220, speed 450. Alpha Whiskey went off line while they figured out what was going on.
Alpha Whiskey came back on line and replied; that bogey is Tiger Airlines flight 203 from Hong Kong.

Tiger Airlines was a CIA airline. I think I know, I’m pretty sure I know what the cargo was, sorry I can’t tell what the cargo was.



I don’t know when IFF (Identification, Friend or Foe) was developed, maybe in the fifties. Every US military plane had it installed. There were 3 modes of operation. When challenged, a plane had its IFF set for either 1 or 2 or 3 pulses sent back to the challenger (a ship or a shore station.)

At some point all navy planes had a newer IFF installed. Mode 1 and 3 were not changed, but mode 2 was modified. Mode 2 not only returned its challenge but there were several pulses that came back to the challenger, the pulses told what the incoming plane was. Each squadron had its own coded sequence. Now on to the story.

The codes were kept in a safe and they changed every day. One Officer from each squadron had to come to my electronics shop for what was (the mode 2 codes). I was running the shop and it was my duty to hand over the codes to the officer who came to get them. Before I could hand over the codes I had to check the officers Identification. The night in question, a navy lieutenant came to the shop, I asked for his ID, he showed me his ID; I looked on the list of which officers supplied by each squadron could get the day’s codes. The officer identified himself. I looked at my list and then said: “I’m sorry sir, but you are not on the list so I can’t give you the codes.” The officer turned red as a beet, furious as I put the codes back in the safe. He was going to have me keelhauled. I very nicely said “I couldn't give the codes to the Captian of the ship if he wasn’t on the list. The officer left in a huff. I began to wonder what punishment I might get for what I did? Soon my shop Chief called and spoke to me, my division officer got a call, likely the Executive Officer got a call from the squadron.

A half hour later an officer from that squadron came in for the codes. I checked his ID, it was on the list so I handed over the codes and that was it. The planes got into the air, they did their job, they came back and landed on the ship. Some North Vietnamese buildings and defense positions and soldiers manning them were killed and the same attacks happened the next morning and afternoon and night. That’s how wars went on back then.