Organisational Breakdown Structure A depiction of the project organisation, arranged so as to relate work packages to organisational units of Eurocontrol. Organises and defines the total scope of the project. Each descending level represents an increasingly detailed definition of a project component. Project components may be products or services. (Source : Project Management Institute PMI - PMBOK guide). Original Notice to Airmen NOTAM as received by the NOTAM Processing Unit. Other Training Device A training machine which presents the student with some operational functions on a non-realistic reproduction of the operational devices. It includes generic MMC. Out of Conformance A flight is out of conformance with its planned trajectory when its current position or altitude deviates in excess of a specified value in relation to the point at which it is expected to be. Outer Marker Marker beacon located 5-7 miles from the end of the runway. Outer Performance Boundary (Tunnel Concept) The OPB refers to certain bounds on the aircraft position (more specifically, the aircraft centre of mass). During the intended operation, the aircraft centre of mass must remain within the bounds containing the desired trajectory with probability 1 - 107. (Outer Tunnel is an alternate term for the OPB). Outlier A measurement (from a radar detection system) that has a (set of) state value(s) outside the three-times-standard-deviation interval around the mean value(s) or outside a user specified limit. Outlier Removed RMS Error Calculation of the RMS error omitting the Outliers. Output The output from a tracker. Output Transition Change in the tracker output (e.g. a Track Swop, or a Track Drop, or a Track Stop). Outputs A generic term meaning various products or services that occur as a result of inputs being applied to a process (or processes) undertaken by an organisation or an individual. Overall (ERSS) When used means that the measurement method shall be applied without geographical restrictions to the whole sample of the recorded data obtained from opportunity traffic. This sample shall be representative of the whole population of aircraft to which Air Traffic Services are provided irrespective of radar cross sections and clutter environments for PSR sensors, and irrespective of transponder deficiencies for SSR sensors. Over-Interrogation Interference in the operation of a secondary radar system due to the fact that the number of interrogations exceeds the capacity of the transponder (a preset value). The action of the transponder is an automatic reduction in transponder receiver sensitivity. Overtime The time during which a person works a job in addition to the regular (statutory) working hours.

 
Owner (of an element of the EMH)
Person who: a) Is able to make immediate changes to the EMH element; b) Has absolute control of the supporting documentation; c) Is accountable for its performance.
P
Pacific Region See ICAO Region.
Packet The basic unit of data transfer among communications devices within the network layer.