Several years ago, Carl Hancock, pilot and host of the YouTube series Fly with the Guys, shared with us the story of a sobering encounter with carbon monoxide (CO). Carl contacted us again recently to tell of another experience with CO. But this is a very different story, because Carl was wearing his Lightspeed Delta Zulu headset, so he was fully aware of the risks and in control of himself and the situation from start to finish.
The first time he was exposed to a dangerous CO level, Carl said he was lucky to have been in a plane using mogas (automotive gas), so he could smell the exhaust. When he then developed a headache, he recognized the onset of CO poisoning and was able to land safely, before becoming too impaired to function safely. A later inspection of the plane revealed that a loose flange on the exhaust manifold had allowed exhaust into the cockpit.
Carl’s more recent encounter with CO occurred earlier this year in a 1965 Cessna 172 recently purchased by his flying club. Carl says he always inspects a new-to-him plane as if it had been in a prior crash, so he had thoroughly inspected this one. Everything looked good, so he took off on a nice, relatively warm January day in Arizona for a shakedown flight.
He took off and began his initial flight pattern without incident, familiarizing himself with the plane and its avionics. Just as he got clearance from ATC to land, his Lightspeed Delta Zulu headset sounded an alarm: CO was at an unsafe level. He’d been flying for about 10 minutes without problems, but clearly something was going on now, so he opened a window. Next, he reached for his headset controller, pushed the button, and the headset reported that the CO level was around 60 parts per million (ppm), well over the dangerous 50 ppm critical threshold.
As he made his approach to land, Carl hit the button again, and the Lightspeed Delta Zulu reported that CO levels were now at 0 ppm. The open window was working, so instead of landing, he decided to do a touch-and-go so he could continue monitoring and gather more information on the CO issue. As he gained altitude again, he closed the window to check how quickly CO was building, using his headset to check the CO level every few seconds. By the fourth or fifth check, the CO level had already increased to 40 ppm, much faster than he had expected, so he reopened the window and decided to terminate the flight.
Unlike Carl’s first experience with CO, this plane was running avgas, so there was no exhaust smell. He had noticed a smell “like running a heater after not using it for some time,” and in hindsight he thinks that must have been from exhaust entering the cabin. But he says, “I can safely say that the only reason I even knew about the carbon monoxide was due to the [Lightspeed] Delta Zulu.” Upon landing, Carl informed the owner about the CO issue.
For Carl, his Lightspeed Delta Zulu headset is his primary source of CO monitoring, especially in club planes, because he never knows how they’ll be equipped with CO monitors: with digital detectors, chemical detector cards, or none at all. He always expects some level of CO on the ground, and he’s used the headset before to check CO levels, but he’d never had an alarm go off before. He didn’t notice if this plane had a CO detector, but he knows that the issue has since been fixed and other club members have flown it without issues. Looking back on the incident, Carl said “Thankfully, I was the one who was in the airplane, with the proper tools to detect the problem before someone else got hurt.”
When asked for his takeaway from this second “close encounter”, Carl told us, “The moral to this story is that CO is no joke, especially when we’re flying airplanes from the ‘60s and ‘70s, but even with new airplanes. So, if you don’t have a way to detect CO, you need to get one. And, honestly, if you’re flying different airplanes in a club or flight school situation, the [Lightspeed] Delta Zulu is probably the best piece of equipment you can have with you.” He adds, “I truly believe in the [Lightspeed] Delta Zulu. It’s saved me at this point, so why would I fly with anything else?”
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