discrimination /d.skr.m.
ne..(.)n/ noun the ability to know or see the difference between two similar things . Targets on the same bearing which are separated radially by less than half a pulse length distance will appear at the receiver as one echo, so good target discrimination requires short pulses.
discuss /d.sks/ verb to write about or talk about a subject . This chapter will discuss HF and VHF voice commu-nications.
disembark /d.s.mbɑk/ verb to
leave the aircraft after landing . The passengers finally disembarked at
20.00 hours.

disembarkation /d.s.mbɑ
ke..(.)n/ noun the act of leaving the aircraft after landing . The exits are used as conventional doors for disem-barkation.
disengage /d.s.ne.d/ verb to
switch off a system or device . Switches on the control columns instantly disen-gage the autopilot when depressed.
dish /d../ noun a shallow container for food
dish antenna /d.. nten./ noun a
circular antenna with a shape like a shallow bowl
disintegration /d.s.nt.re..(.)n/
noun the falling apart or destruction of something . Electromagnetic radia-tions resulting from the disintegration of radioactive materials are known as gamma rays.
dismantle /d.smnt(.)l/ verb to take apart into single components . One type of inspection is able to reveal fatigue cracks, corrosion, internal dam-age, the presence of loose articles and mercury spillage without the need to dismantle the aircraft. Opposite
assemble (NOTE: The verb ‘mantle’ is not used.) disorientation /d.s.ri.nte..(.)n/
noun a state of confusion in which there is loss of understanding of where one is or which direction one is facing, etc. .
When the cabin is rapidly and com-pletely filled by smoke and fumes pas-sengers will suffer from disorientation.
dispensation /d.spense..(.)n/
noun permission not to have to do something . At very high altitudes the flying pilot must be on oxygen at all times, unless an aircraft dispensation has been obtained.
dispense /d.spens/, dispense with
verb not to include or not to use some-thing . In some cases the rivets are dis-

dispersal 74
pensed with and the skin is fixed to the internal members by the redux process.
dispersal /d.sps(.)l/ noun 1. the act of leaving an area and going in dif-ferent directions . the dispersal of a crowd the disappearance of a crowd 2. the clearing away of something such as mist, e.g. by the wind . the dispersal of hill fog . Dispersal of cloud takes place when surface heating lifts the cloud base or drier air is advected.
disperse /d.sps/ verb 1. to leave an area going in different directions . the crowd dispersed the people in the crowd left the area, going in different directions, so that eventually the crowd disappeared 2. to clear away . The fluo-rescent green dye will disperse slowly in a calm sea but quickly in a moderate to rough sea.