Powerplants and Flight Instruments
Engines and the instrument panel
This domain links powerplant knowledge to the instruments that monitor it: tachometer, manifold pressure gauge, exhaust gas temperature, cylinder head temperature, fuel flow, and oil pressure and temperature. Candidates must understand how manifold pressure and RPM relate to power output, the purpose of the mixture control, and the indications of detonation and pre-ignition. Know the normal operating ranges and what an abnormal indication implies.
Traps
Questions often test the relationship between manifold pressure and throttle position at altitude, or the meaning of a rising cylinder head temperature in a climb. Another trap is confusing detonation (uncontrolled combustion after ignition) with pre-ignition (ignition before the spark). Watch for questions on the turbocharger and wastegate, and on the correct leaning procedure at altitude.
Worked example
In a climb at full throttle, manifold pressure decreases as altitude increases because ambient pressure falls. If CHT rises toward the limit, enrich the mixture and reduce the climb rate to improve cooling.
Rule of thumb
Power is a function of manifold pressure and RPM; mixture affects temperature and fuel flow. Lean for altitude, enrich for cooling and power.
Communications, Surveillance and Operational Procedures
Talking and being seen
Candidates must understand standard radiotelephony phraseology, readback requirements, and the meaning of clearances that contain route, altitude, and frequency changes. Know the surveillance systems: secondary surveillance radar with Mode A, C, and S, and ADS-B with its extended squitter. Understand transponder codes, the meaning of code 7500, 7600, and 7700, and when to use them. Know the requirements for radio failure procedures in IMC and the meaning of "lost comm" routing.
Traps
Questions often test whether a readback is required for every clearance (it is for altitude and route clearances) and what to do when a transponder fails in controlled airspace. Another trap is confusing the emergency codes or assuming ADS-B replaces the transponder. Watch for questions on the phraseology for position reports and on the correct response to a radio failure.
Worked example
If you lose radio communication in IMC, follow the published lost-communication procedure: continue on the last assigned route and altitude, then follow the expected further clearance or the filed route, and land at the destination or alternate as applicable.
Rule of thumb
7500 (hijack), 7600 (radio failure), 7700 (emergency). Read back altitude and route clearances; when in doubt, ask.