Type letter symbols:
engine that requires minor changes, the Air Force
uses the Navy-type designation and assigns its own
J . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbojet
model designation. It begins with the number 1
and progresses with consecutive odd numbers to
T
. . . . . . . . . . . . . . . . . . Turboshaft,
turboprop
the modified engine. This model number is
actually a modification number that tells which
F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbofan
service made the last production change in it for
a particular aircraft.
Each service consecutively assigns type
numbers with the type letter symbol. Beginning
For example, J79-GE-10 breaks down as
type numbers for the three armed services are:
follows:
100. . . . . . . . . . . . . . . . . . . . . . . . . Air Force
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbojet
J
400 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Navy
79 . . . . . . . . . . . . . . . . . . . Air Force developed
700 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Army
GE . . . . . . . Manufactured by General Electric
Company
10 . . . . . . . . . . . . . . . . . . . . . . . . . . Navy model
Manufacturer's Symbols
and
The second part of the designation consists of
a dash and a two-letter symbol showing the
T56-A-16
manufacturer, as follows:
T . . . . . . . . . Turbine (turboprop in this case)
AiResearch Division, Garrett Corp. . . . . . GA
56 . . . . . . . . . . . . . . . . . . . . . . . Navy sponsored
Allison Division,
General Motors Corp . . . . . . . . . . . . . . . . ..AD
A . . . . . . . . . . . . . . . . Manufacturer (Allison)
Continental Aviation
16 . . . . . . . . . . . . . . . . . . Eighth model (Navy)
and Engineering Corp . . . . . . . . . . . . . . . . ..CA
General Electric Company . . . . . . . . . . . . . GE
MIL-STD-879
Lycoming Division, Avco Corp. . . . . . . . . LD
The new system applies to all the armed
Pratt and Whitney Aircraft Division,
services--Army, Navy, and Air Force. It consists
United Aircraft Corp . . . . . . . . . . . . . . . . . .PW
of three parts; a type indicator, manufacturer's
symbol, and a model indicator. All newly
Rolls Royce, Ltd . . . . . . . . . . . . . . . . . . . . . .RR
developed gas turbine engines use this designation.
Existing engines change to a new three-digit model
United Aircraft of Canada, Ltd. . . . . . . . . CP
number with major changes in configuration or
design. However, the engine usually keeps the old
Curtiss-Wright Corp . . . . . . . . . . . . . . . . . . .WA
two-digit type indicator.
Special manufacturer symbols show when two
Special designations (X or Y) used in the new
manufacturers are jointly producing an engine.
system are the same as the old system.
In that case, the manufacturer symbol consists of
one letter from the symbol for each manufacturer.
Type Indicator
NOTE: Manufacturer letter symbols are
not the same as manufacturer code sym-
The type indicator, the first part of the
bols. The code symbols are with the
designation, consists of the appropriate type
Federal Supply Code for manufacturers.
letter symbol together with the type numeral.
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