Incident Overview
On March 8, 1982, a Boeing 707-131 owned and operated by TWA was undergoing routine maintenance at Las Vegas, Nevada. During the check, the servicing valve on the forward water tank would not open. A TWA mechanic entered the forward electronics bay to inspect the valve control mechanism while the lead mechanic operated the valve from outside. The valve operated normally, and the lead mechanic yelled "It's OK." Shortly thereafter, another mechanic looked into the compartment, did not see anyone, and secured the hatch. The mechanic's absence was not noticed until the next day.
Discovery
On March 9, 1982, the aircraft flew to St. Louis, Missouri, where the mechanic's body was discovered after a search was initiated by the Las Vegas station manager.
Autopsy Findings
An autopsy revealed that the mechanic was electrocuted after coming into contact with several 115-volt relays in the electronics compartment. Injuries found during the autopsy indicated that the mechanic slipped and struck his head before falling onto the relays.