FAA multi-engine airplane class-rating foundations common mistakes
FAA multi-engine airplane class-rating foundations · Understand the traps and how to avoid them.
Calling Vmc the speed that guarantees single-engine climb.
Directional control and available excess power are confused.
What to do instead
Check control limits and actual approved performance separately.
Calling every left engine critical without checking rotation.
A conventional-twin memory rule becomes universal.
What to do instead
Establish the actual configuration and stated viewing reference.
Treating blade angle and angle of attack as identical.
Their reference directions are different.
What to do instead
State the chord, rotation plane and relative airflow separately.
Calculating percentage slip using an unstated denominator.
A distance difference is converted into a different percentage measure.
What to do instead
Use the denominator specified by the exercise and retain consistent units.
Assuming pressure loss always sends blades to fine pitch.
One design's opposing forces are transferred to all propellers.
What to do instead
Identify oil direction, springs, counterweights and the actual installation.
Measuring feather angle from the shaft but quoting a rotation-plane value.
Two complementary references are confused.
What to do instead
Keep the stated reference plane and physical alignment explicit.
Equating equal RPM with correct phase and balance.
Different system checks are treated as one measurement.
What to do instead
Assess synchronization, phase, track and balance according to their separate functions.
Calling current draw proof that every blade heats correctly.
Circuit supply is confused with correct distribution and element condition.
What to do instead
Compare the expected sequence and actual component tests under approved data.
Assuming two engines mean half the original climb remains after failure.
Increased drag and the excess-power relationship are ignored.
What to do instead
Use the actual approved engine-out data and conditions.
Feathering based solely on a foot-pressure mnemonic.
A cue is treated as conclusive verification.
What to do instead
Follow the actual aircraft identification, cross-check and verification procedure.