HDG  Heading:.The.angular.relation.of.the.longitudinal. axis.of.the.aircraft.with.respect.to.a.reference.. Magnetic.heading.is.referenced.to.magnetic. north..True.heading.is.reference.to.true.north.
HDGSEL  Heading.Select
HDISK  Hard.Disk
HDL  Hybrid.Data.Link
HDLC  High-Level.Data.Link.Control
HDLC-B  High-Level.Data.Link.Control-Balanced
HDLMS  Hybrid.Data.Link.Management.System
HDOP  Horizontal.Dilution.of.Precision
HDOT  Inertial.Vertical.Speed
HDP  Hardware.Development.Plan
HE  Altitude.Error
Heading  The.direction.of.an.aircraft.path.with.respect.to.
magnetic.or.true.north.
HERF High Energy Radio Frequency Interference HF ( 1 ) High Frequency. The portion of the radio
spectrum.from.3.to.30.MHz..HF.communication.
systems.operate.in.the.2.to.30.MHz.portion.of.the.
spectrum...
(.2.).Human.Factors

HFDL  High-Frequency Data Link
HFDM  HF.Data.Modem
HFDR  High Frequency Data Radio
HFNPDU  High Frequency Network Protocol Data Unit
HFS  High Frequency System
HFSG  Human.Factor.Study.Group
HFSNL  HF.Sub.Network.Layer
HGA  High.Gain.Antenna
HGC  Head-Up.Guidance.Computer
HGS  (.1.).Head-Up.Guidance.System..
(.2.).HUD.Guidance.System

HHLD Heading.Hold HI High HIC (.1.).Head.Impact.Criteria.
(.2.).Head.Injury.Criteria
HIL  Horizontal.Integrity.Limit
HIRF  (.1.).High.Intensity.Radiated.Field.
( 2 ) High Intensity Radio Frequency
HLCS High.Lift.Control.System HLE Higher.Layer.Entity HLL High.Level.Language HM Health.Management HMF Health.Management.Function HMI Human.Machine.Interface HMOS High Density Metal Oxide Semiconductor HMU Height.Monitoring.Unit HO Handoff HOLD Holding.Pattern HOW Hand Over Word HP (.1.).High.Pressure..
(.2.).Holding.Pattern