Aeroplane Systems and Performance
Core systems knowledge
A candidate for the IATRA must be fluent in the aeroplane's powerplant, fuel, electrical, hydraulic, flight-control, ice-protection, and pressurization systems at the level of what happens and why. Know the difference between a normally aspirated and a turbocharged engine, how a constant-speed propeller governor responds to an overspeed, and why a failed alternator may leave you with a battery-only electrical supply and a time limit. Understand that a vacuum-driven attitude indicator and a vacuum-driven heading indicator both fail when the vacuum pump fails, and that the turn coordinator is electrically driven on many light twins.
Performance fundamentals
Performance questions test whether you can apply the POH rather than memorize numbers. Distinguish pressure altitude from density altitude, and remember that density altitude is pressure altitude corrected for non-standard temperature. Takeoff and landing distances are tabulated for given weight, altitude, temperature, wind, and runway slope; each correction is applied in the sequence the POH specifies. Climb performance degrades with altitude, and single-engine climb performance in a light twin is often near zero at high density altitude - a favourite trap.
Traps
Watch for questions that give a headwind component on takeoff and a tailwind on landing, or that ask for ground roll versus total distance over a 50-foot obstacle. Weight-and-balance questions often hide a moment-arm unit conversion.
Rule of thumb
Density altitude rises roughly 120 feet for every 1°C above standard temperature at a given elevation. A 15°C day at 4,000 feet pressure altitude is about 1,800 feet of density altitude penalty relative to standard - enough to change your takeoff roll materially.