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H
H 1 Henry.
2 Total pressure.
3 Enthalpy.
4 High (synoptic chart).
5 High-altitude-class Vortac/Tacan or Route Chart.
6 NDB 50-1,999 W.
7 Angular momentum.
8 Helicopter mission category, USAF since 1948,
USN since 1962, or helicopter qualification [PPL].
9 US military aircraft modified mission prefix,
search/rescue and aerial recovery (DoD).
10 Magnetizing force; horizontal component of Earth’s
field, See H V below.
11 Stored in silo but raised to surface for launch (DoD,
ICBM).
12 Hard temper (light-alloy suffix).
13 G/S home from CP.
14 Airway or map prefix, helicopter route.
15 Ambulance [hospital] category (USN 1929-31, 1942-
44).
16 Transfer function.
17 Health (facility or RAF).
18 Piston engine with two crankshafts and parallel
opposed cylinders.
19 Hard surface [airfield].
20 Haze.
21 Homing [beacon].
22 Hold, followed by direction.
23 Heavy.
24 Hazard.
25 Heliport.
26 Geometric altitude, or height of aircraft c.g. when on
ground.
27 Hydrogen [see H 2 ].
28 Maximum section height (tyre).
29 Propeller pitch [P more common].
30 Aircraft category. VTOL aircraft [but see category
M] (FAI).
31 Hankel function.
32 High-intensity [airfield lighting].
h 1 Hour[s].
2 Prefix hecto = 10 2 .
3 Hexode, heptode (ambiguous).
4 Hangarage available.
5 High (synoptic chart).
6 Heater (electronics).
7 Height above MSL, or height difference in flight
trajectory.
8 Specific enthalpy.
9 Planck constant, = 6.62559 10 –34 Js.
10 Height of blade CP above flapping axis.
11 Operator, 120° (electrical).
12 CC blowing jet slit height (also hj).
13 Distance measured across chord from leading edge
divided by MAC.
14 Subscript, hover.
H+, H-
H-hour.
H V Magnetic field, Am -1 .
Hours plus or minus minutes, eg related to
h 1 , ḣ Vertical velocity. Suffixes for glide-slope (GS), flare
trajectory (FL) and reference trajectory (REF).
H 2 Gaseous hydrogen.
H24, H 24 Continuous-service airfield or facility.
H 2 S Original PPI mapping radar (UK, WW2).
H 2 X Development of H s S at shorter wavelength in US
(see mickey, BTO).
H-83282 Highly stable non-inflammable synthetic
hydraulic fluid (USN).
H-bomb Hydrogen bomb.
H-display B-display with elevation angle indicated;
target appears as bright line with slope proportional to sin
elevation.
h-dot See h 1 , h .
H-engine Piston engine with left and right rows of
vertical opposed cylinders, two crankshafts geared to
central output.
H-force Helicopter main-rotor drag.
H-hour Start of war, esp. time first landing aircraft
reaches LZ, or similar clearly defined action.
H-film Kapton hi-temperature polyimide.
H-plane Plane of antenna’s magnetic field, normal to E-
plane.
H-Pres Pressure altitude.
H-tail One having twin fins on tips of tailplane.
HA 1 Height of apogee.
2 Hour angle.
3 High altitude.
4 Housing allowance.
ha Hectare[s], = 10 4 m 2 .
HAA 1 Helicopter Association of America [office
Washington DC].
2 Height above airport.
3 Historic Aircraft Association [1978–; office
Leamington CV32 6NQ] (UK).
4 Heavy anti-aircraft [gun, or fire].
5 High-altitude airship.
6 Helicopter Association of Australia.
HAAP Helicopter approach aiming point.
haar Wet sea fog (UK, North Sea).
HAARP Hf active auroral research program (ONR).
HAARS High-altitude airdrop resupply system.
HAATR Highly accurate autonomous target recognition
[C adds capability].
HAB Heliport acquisition beacon.
HABM Hypervelocity air-breathing missile.
haboob Line squall causing severe dust storm.
HABV Hypersonic air-breathing vehicle.
HAC 1 House Appropriations Committee (US
Congress).
2 Hover/approach coupler.
3 High-acceleration cockpit.
4 Hélicoptère anti-char (F).
5 Helicopter aircraft controller.
6 Helicopter active control.
7 Heading alignment cone.
8 Helicopter Association of Canada.
Hacienda Office of Aerospace Research (USAF,
colloq.).
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