MD-11
Maintenance Airframe; Maintenance Powerplant
Distraction; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Other / Unknown
Flight Crew Diverted; General Maintenance Action
Aircraft; Human Factors; Incorrect / Not Installed / Unavailable Part
Flight arrived at ZZZ. Performed exterior postflight inspection. Maintenance action was required for the lower beacon and VHF3; visually inspected both wing engines; visually checked oil quantity using the glass sight on the oil tank; noted oil quantity was within limits; no oil was added. Closed access doors and removed ladder. Flight diverted to ZZZ1 due to #1 Engine oil pressure low. Found #1 Engine oil cap off; not secure.
A Line Aircraft Maintenance Technician reported he performed a post flight exterior inspection of an MD-11 aircraft that included visually checking the engine oil quantities using the sight glass on the oil tanks. No oil was added. The flight later diverted due to low oil pressure on #1 engine. The oil tank cap was found off and not secured.