Retired Navy Capt. Charlie Plumb learned the secret to communicating with other prisoners of war in Vietnam through a note written on a piece of toilet paper pushed through the wall.

The note was written with ink made with ashes and a quill made from bamboo, he recalled, and it taught him the code for tapping out letters on walls.

Communication was dangerous but critical during the six years that Plumb and retired Air Force Maj. Gen. Edward Mechenbier were held as prisoners of war after the two pilots were shot down over Vietnam in 1967.

“Communication and humor was sometimes that thread that kept us together and helped us survive,” said Air Force Academy graduate Mechenbier, during a panel at the academy recently. The two appeared during the annual National Character and Leadership Symposium.

Amid the torture and sickness in captivity, news from the tap code, carried hope, they said. In one case, prisoners passed along word of a solid bowel movement, the first years, from building to building through a prison camp called The Zoo, Mechenbier said.

 It was big news in an environment where word of a prisoner “fathering” a parasite in his waste was far more common.

The tap code also let leadership give orders, such as not to bow to prison guards, Plumb said.

“It scared them to death to think we had that kind of communication,” he said. It also gave the prisoners some confidence.  

At one point, the fighter pilots started flipping each other off when they saw each other, which made the guards think that’s how Americans greeted each other. When the guards adopted the gesture with Americans, it allowed the pilots to respond in kind, Mechenbier recalled.

In the first few months of imprisonment, Plumb recalled he was angry, but as he talked with now-retired Rear Adm. Bob Shumaker, advised that it wasn’t productive.  

Plumb recalled learning from that conversation via tap code that “Acid does more harm in the vessel it’s stored in than on the subject it’s poured.” He has since forgiven his captors.

The end of the war and freedom for the POWs, came with a sense of euphoria for some, Mechenbier said.

“A lot of us felt awful damn lucky that we came home,” he said. He was among 66 pilots who received orders to go to Vietnam while they were stationed in England. Thirty-three were shot down and Mechenbier was one of four who survived.

The heroes welcome the POWs received at the end of the war, with ticker tape parades and media engagements, helped with the transition back home, Plumb said.

Among all the POWs who survived, 95%, stayed in the military and continued to lead at high levels, Plumb said.

“We didn’t feel like heroes, but we felt like the nation needed heroes,” he said.