ENGINE INSTRUMENT SYSTEMS
ENGINE INSTRUMENT SYSTEMS
I. Introduction
A. Purpose – measure and indicate the operation of the engine
B. Measuring (or sensing) and Indicating
1. Measuring – sending unit or sensor detect temperature, pressure, speed, etc.
2. Indicating – indicating unit or gauge displays data for the operator to use
3. Examples – engine instrument systems include:
a. Tachometer – indication of engine crankshaft speed in Rpm
b. Manifold absolute pressure (MAP) – indication of pressure in the induction system (intake manifold or valve) in inches of mercury
c. Oil pressure – indication of oil pressure in main galley, after pump, in psi
d. Oil temperature – indication of oil temperature, after the oil cooler
e. Cylinder head temp (CHT) – indication of (hottest) cylinder temperature
f. Fuel pressure – indication of fuel pressure, typically in psi
g. Fuel flow – indication of rate of fuel flow/”burn” in gal or lbs. per hour
h. Exhaust gas temperature (EGT) – indication of (hottest) cylinder exhaust
i. Carburetor air temperature (CAT) – indication of temperature in carburetor
j. Turbine inlet, outlet, or interstage temps (TIT, TOT, ITT) – indicate turbine gas flow temperatures
II. Requirements (14 CFR 23)
A. Markings
1. Radial line – indicates minimum or maximum limits
2. Arc – indicates an allowable operational range
3. Typically directly on instrument face, but may be painted on the instrument glass
4. Index mark – white mark on glass, “slippage marks” (used where color markings are on the glass), extends from glass onto case
B. Colors
1. Green arc – safe, or normal range of operation
2. Blue line/arc – allowable value under special operating conditions
3. Yellow arc – caution range, typically -time or -condition limited operation
4. Red radial/line – unsafe, maximum or minimum safe operating limits
C. AMT Privileges – as related to instruments themselves – very limited
1. “steam Gauges/ Round Dial”
a. Can inspect for installation, condition, mounting, marking and operation of
I. Introduction
A. Purpose – measure and indicate the operation of the engine
B. Measuring (or sensing) and Indicating
1. Measuring – sending unit or sensor detect temperature, pressure, speed, etc.
2. Indicating – indicating unit or gauge displays data for the operator to use
3. Examples – engine instrument systems include:
a. Tachometer – indication of engine crankshaft speed in Rpm
b. Manifold absolute pressure (MAP) – indication of pressure in the induction system (intake manifold or valve) in inches of mercury
c. Oil pressure – indication of oil pressure in main galley, after pump, in psi
d. Oil temperature – indication of oil temperature, after the oil cooler
e. Cylinder head temp (CHT) – indication of (hottest) cylinder temperature
f. Fuel pressure – indication of fuel pressure, typically in psi
g. Fuel flow – indication of rate of fuel flow/”burn” in gal or lbs. per hour
h. Exhaust gas temperature (EGT) – indication of (hottest) cylinder exhaust
i. Carburetor air temperature (CAT) – indication of temperature in carburetor
j. Turbine inlet, outlet, or interstage temps (TIT, TOT, ITT) – indicate turbine gas flow temperatures
II. Requirements (14 CFR 23)
A. Markings
1. Radial line – indicates minimum or maximum limits
2. Arc – indicates an allowable operational range
3. Typically directly on instrument face, but may be painted on the instrument glass
4. Index mark – white mark on glass, “slippage marks” (used where color markings are on the glass), extends from glass onto case
B. Colors
1. Green arc – safe, or normal range of operation
2. Blue line/arc – allowable value under special operating conditions
3. Yellow arc – caution range, typically -time or -condition limited operation
4. Red radial/line – unsafe, maximum or minimum safe operating limits
C. AMT Privileges – as related to instruments themselves – very limited
1. “steam Gauges/ Round Dial”
a. Can inspect for installation, condition, mounting, marking and operation of