Unfortunately, knowing which parts of planes should not be touched, and what a ladder looks like is a skill set that still needs some fine tuning.
According to this ABC News report, an inspector at Chicago’s O’Hare Airport used sensitive instrument probes as handholds while climbing into nine American Eagle airplanes. These TAT probes, pictured, are important to the operation of flight computers. As a result, 40 commuter flights were delayed.
At the time, the TSA agent was attempting to determine if the aircraft could be broken into and an agency official is quoted as saying “Our inspector was following routine procedure for securing the aircraft that were on the tarmac.”
Next time, try using a ladder and a brick.