TB 55-9150-200-24
(2) TCP transforms lead deposits to phosphorus compounds, thus altering the electrical and temperature
characteristics of the deposits which reduce spark plug fouling and preignition. TCP only helps relieve spark plug lead
fouling in reciprocating engines using highly leaded fuels, especially in those engines operating on a lean mixture. It
does not help when an engine is operating under rich fuel mixture conditions. TCP will not help in the resolution of
problems involving engine power loss, excessive oil pumping, carburetor icing, valve-sticking, or the elimination of
deposits. TCP is not a cure-all.
(3) The following procedures will be used to blend TCP with AVGAS. To treat a full 55 gallon drum of
AVGAS, pour the entire contents of one 200 ml can of MIL-T-9188 type III TCP into the drum. The drum then will be
rolled a minimum of 100 feet or agitated long enough to insure thorough mixing. Under no circumstances will TCP be
introduced directly into aircraft fuel tanks because of the impossibility of proper blending.
WARNING
The majority of problems resulting from the use of TCP can be traced to incomplete mixing
with fuel. Complete blending is necessary.
(4) The use of fine wire platinum spark plugs and TCP is helpful in lessening the problems caused by the use
of leaded AVGAS.
WARNING
TCP is a toxic chemical. If TCP comes in contact with the skin, affected areas should be
washed immediately with soap and water. Precautions should be observed to prevent
inhalation of TCP vapors.
Section III. TABLES, FUELS AND FUEL SPECIFICATIONS
Table 2-1. Mixing Ratios
Static Fuel System Tests
Liquid Dye
NSN
Unit of Issue
MIL-SPEC
Mixing Ratio
Red
2 ounces
Add 2 ounces
Red
1 gallon
to each 100
Yellow
1 gallon
gallons of fuel.
Run-Up and Inflight Fuel System Tests
Liquid Dye
NSN
Unit of Issue
MIL-SPEC
Mixing Ratio
Yellow
1 gallon
Add 1.6 ounces
to each 100
gallons of fuel.
2-6
