Fumes in the cockpit
For an MD-83 flight crew, fumes in the cockpit led to the discovery of an unexpected source.
Level at 33,000 feet...a strong odor similar to paint thinner was detected by both pilots. Cockpit crew initiated a fume checklist. After securing mask and goggles, cockpit crew established communications with flight attendants. The number one flight attendant reported that he also smelled a strong odor and a flight attendant in the aft of the aircraft also reported an odor. Since we were not able to determine the source of the strong odor, and considering that all of the flight crew reported noticing the smell, the flight crew determined that an emergency should be declared, followed by a divert to ZZZ. After declaring the emergency, ATC cleared the flight to turn 180 degrees for vectors toward ZZZ. As the aircraft was in the turn, the number one flight attendant called the cockpit and informed the crew that the source of the fume-like odor was identified. Apparently, two children sitting in First Class had just begun to color with ink markers. The flight attendant reported, without a doubt, that the smell was coming from the ink being applied to the paper. This was verified by the other flight attendants working the flight, as well as by a pilot in uniform commuting to work. The number one flight attendant reported that the marker is printed with a warning to avoid use of the marker at high altitudes, or in confined spaces....
ATC was then informed that we discovered the source of the unusual odor, and that the situation was now safe and under control. We rescinded the emergency declaration and requested vectors to continue the flight on to our destination. We landed on time, without incident.
Source: Nasa Callback