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alkali metal
alkali metal Group of metals in First Group of Periodic
Table characterised by single electron in outermost shell
which they readily lose to form stable cation (thus,
strongly reactive). Lithium, sodium, potassium and
caesium (cesium) are important in electrical storage
batteries and as working fluids in closed-circuit space
power generation.
alkylation Addition of alkyl group (generally, radical
derived from the aliphatic hydrocarbons); important in
manufacture of gasolines (petrols) having high anti-knock
(octane) rating.
ALL Airborne laser laboratory.
ALLA, Alla Allied Long Lines Agency (NATO).
all-black Made entirely of [not necessarily black ]
composite material
all-burnt Rocket propulsion system which has
consumed all propellant (where there are two, which has
consumed all of either); specif., time and flight parameters
when this occurs.
all-call Transponder Mode-S broadcast interrogation,
thus * address, * reply.
ALLD Airborne laser locator designator.
alleviation Reduction of structural loads (eg wing
bending moment) in vertical gusts by active controls.
alleviation factor Numerical multiplier of calculated
vertical acceleration or structural load on encountering
gust, taking into account fact gust is not sharp-edged and
aircraft is already rising before peak intensity is reached.
Later refined by making it a function of the ratio of mean
chord to gradient distance, aspect ratio and mass parameter.
alleviation lag Time difference between actual and ideal
response of a GAC active control system.
alleviation technique Method of reducing heat flux on
atmospheric re-entry by controlling plasma sheath
surrounding vehicle.
all-flying tail Term formerly used to describe variableincidence
tailplane used as primary control surface in
pitch, separate elevators serving merely as additional part
of surface or as a means of increasing camber.
Al-Li Aluminium-lithium alloys.
Alliance ground surveillance Programme for reconnaissance
aircraft (NATO 1980, approved 1993, operational
possibly 2010).
allithium Generic name for aluminium-lithium alloys;
also (capital A) trade name.
ALLM Aft lower-lobe module (AEW radar).
all-moving tail All-flying tail.
‘all out’ Signal signifying glider or other towrope taut,
towed vehicle ready for takeoff.
allowable deficiency Missing, damaged, inoperative or
imperfectly functioning item which does not invalidate C
of A and does not delay scheduled departure (eg, rudder
bias system, fuel flowmeter and almost any item not part
of structure or aircraft system). In US called despatch
deviation or MEI (1).
allowance 1 Intentional difference between dimensions
(with tolerances permitted on each) of mechanically
mating parts, to give desired fit.
2 Calculated quantity of fuel beyond minimum needed
for flight carried to comply with established doctrine for
diversion, holding and other delays or departures from
ideal flight plan.
along and across
3 In sheet-metal construction, extra material needed to
form bend of given inside radius and angle.
alloy Mixture of two or more metals, or metal-like
elements, often as solid solution but generally with
complex structure. Small traces of one element can exert
large good or bad influence. Most aircraft made principally
of alloys of aluminium (about 95%, rest being
copper, magnesium, manganese, tin and other metals) or
titanium (commercially pure or alloyed with aluminium,
vanadium, tin or other elements), with steels (alloys of
iron) at concentrated loads.
all-shot Aerial target hit by every round from one
gunnery pass.
all-speed aileron Lateral-control surface operable
throughout flight envelope, as distinct from second
aileron group on same aircraft operable at low speeds
only.
‘all systems go’ Colloq., absence of mechanical malfunction;
not authorised R/T procedure.
ALLTV All light-levels TV.
all-up round Munition, especially guided missile,
complete and ready to fire.
all-up weight See AUW.
all-ways fuze Fuze triggered by acceleration in any
direction exceeding specified level.
all-weather Former category of interceptor which could
not, in fact, fly in **. Strictly true only for aircraft with
triplex or quad AFCS and blind landing system plus
ground guidance.
all-wing aircraft Aerodyne consisting of nothing but
wing. Some aeroplanes of 1944–49 were devoid of
fuselage, tail or other appendages, and approached this
closely.
ALM 1 Air loadmaster.
2 Air-launched munition[s]; IPT adds integrated
project team.
3 Aircraft line maintenance.
4 Air and littoral manoeuvre (DSTZ).
ALMD Airborne laser mine-detection; S adds system.
ALMS 1 Aircraft landing measurement system, typically
using IR beams and geophones to produce
hard-copy print-out of final approach and touch-down.
2 Air lift management system (software).
ALMV Air-launched miniature vehicle [A-sat].
Alnico Permanent-magnet materials (iron alloyed with
Al, Ni, Co – hence name – and often Cu) showing good
properties and esp. high coercive force.
Alnot Alert notice.
ALNZ The Air League of New Zealand Inc. [office,
Wellington].
ALO Air Liaison Officer.
ALOC Air line of communication, airlift for spare parts
(USA).
Alochrome Surface treatment for light-alloy structure to
ensure good key for paint: chemical cleaning, light etching
and final passivating.
Alodine Proprietary treatment similar to Alochrome.
Aloft Airborne light-optical-fibre technology.
Alofts Active low-frequency towed sonar [H adds helo].
AlON, ALON Aluminium oxynitride.
along and across Configuration of track position display
unit in which separate windows show continuous reading
of distance to go (along) and distance off track (across),
usually driven by Doppler.
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