(b)
180 feet, plus the wingspan of the most demanding airplane, plus 20 feet per 1,000 feet of airport elevation.

(2) For runways serving only small airplanes:
(a) feet for precision instrument runways.

(b)
feet for other runways serving small airplanes with approach speeds of 50 knots, or more.

(c)
120 feet for other runways serving small airplanes with approach speeds of less than 50 knots.

b.
Inner-approach OFZ. The inner-approach OFZ is a defined volume of airspace centered on the approach area. The inner-approach OFZ applies only to runways with an approach lighting system. The inner-approach OFZ begins 200 feet from the runway threshold at the same elevation as the runway and extends 200 feet beyond the last light unit in the approach lighting system. The width of the inner-approach OFZ is the same as the runway

OFZ and rises at a slope 50 of (horizontal) to 1 (vertical) from beginning.
c. Inner-transitional OFZ. The inner transitional surface OFZ is defined volume of airspace along the sides of the runway and inner-approach OFZ and applies only to precision instrument runways. The inner-transitional surface OFZ slopes 3 (horizontal) to 1 (vertical) out from the edges of the runway OFZ and inner-approach OFZ to a height of 150 feet above the established airport elevation.
OBSTRUCTION (P/CG) - Any object/obstacle exceeding the obstruction standards specified by Federal Air Regulations Part 77, Subpart C.
OBSTRUCTION (NATO) - Any object that rises far enough above the surrounding surface or above a specified height to create a hazard to aircraft in flight.
OBSTRUCTION LIGHT - A light, or one of a group of lights, usually red or white, frequently mounted on a surface structure or natural terrain to warn pilots of the presence of an obstruction.
OCEANIC AIRSPACE (P/CG) - Airspace over the oceans of the world, considered international airspace, where oceanic separation and procedures per the International Civil Aviation Organization are applied. Responsibility for the provisions of air traffic control service in this airspace is delegated to various countries, based generally upon geographic proximity and the availability of the required resources.
OCEANIC DISPLAY AND PLANNING SYSTEM - (P-CG) - An automated digital system which provides flight data processing, conflict probe, and situation display for oceanic air traffic control.
OCEANIC NAVIGATIONAL ERROR REPORT - A report filed when an aircraft exiting oceanic airspace has been observed by radar to be off course. ONER reporting parameters and procedures are contained in FAA Order 7110.82 Monitoring of Navigational Performance In Oceanic Areas.
OCEANIC PUBLISHED ROUTE (P/CG) - A route established in international air-space and charted or described in flight information publications, such as Route Charts, DoD Enroute Charts, Chart Supplements, NOTAM's and Track Messages.