NCAA PPL Flight Performance & Planning cheat sheet

Weight and balance uses the datum as a fixed reference plane; arms are horizontal distances from the datum, and the sign convention (arm forward of datum negative, aft positive) must be applied consistently.

Moment = weight × arm. Total moment divided by total weight gives the centre of gravity arm; the result must fall inside the forward and aft CG limits for the actual takeoff weight.

Empty weight and empty-weight CG come from the aircraft weighing report and include unusable fuel and full oil; operating items (crew, baggage, usable fuel, payload) are added separately as variable load.

Maximum takeoff weight, maximum landing weight, maximum zero-fuel weight and maximum ramp weight are separate limits; a flight can be legal at takeoff yet illegal at landing if fuel burn is insufficient.

Zero-fuel weight = takeoff weight minus usable fuel; it protects the wing root bending case, so exceeding MZFW is prohibited even when total weight is below MTOW.

Forward CG increases nose-down pitch authority demand, lengthens takeoff run and reduces cruise speed and range; aft CG shortens static stability and can reduce stall recovery margin.

Moving a load: shift distance = (total weight × CG shift) ÷ load weight. Adding or removing a load changes both total weight and total moment, so recompute rather than extrapolate.

Load sheet cross-check: total moment ÷ 100 (or ÷ 1000) gives the index units used on the trim sheet; verify the index-to-CG conversion table applies to the specific aircraft variant.

Density altitude = pressure altitude + 120 × (OAT − ISA temperature at that level); ISA temperature = 15 °C − 2 °C per 1000 ft. Use it for takeoff, climb and landing tables.

Takeoff and landing distances from the AFM are factored: dry runway dispatch uses 1.0, wet uses 1.15 on the landing distance, and contaminated runways require the manufacturer's contaminated data.

V speeds: V1 is the decision speed at which a continued takeoff is assured; VR is rotation; V2 is takeoff safety speed reached at 35 ft; VREF is the 1.3 × VS0 (or AFM) landing reference speed.

Climb gradients: a twin-engine transport must show 2.4 % second-segment gross gradient (1.5 % net) with one engine inoperative; PPL light twins are limited by the AFM single-engine service ceiling.

Crosswind and tailwind components: crosswind = wind speed × sin(angle), headwind = wind speed × cos(angle). Most light aircraft have a demonstrated crosswind of 15–17 kt, which is a limitation only if the AFM states so.

Runway slope affects acceleration: uphill slope reduces acceleration and adds roughly 5–10 % to takeoff distance per 1 % upslope on light aircraft; downslope shortens takeoff but lengthens landing.

Stall speed varies with the square root of load factor: VS at load factor n = VS1g × √n. A 60° bank in level flight gives n = 2 and a 41 % higher stall speed.

Hydroplaning (aquaplaning) dynamic speed in knots ≈ 9 × √(tyre pressure in psi); above that speed on standing water, braking and nosewheel steering degrade sharply.

Fuel plan: trip fuel + contingency (typically 5 % of trip fuel) + alternate fuel + final reserve (30 min holding at 1500 ft above destination for light aircraft) + taxi fuel = minimum required fuel.

True airspeed from indicated: TAS ≈ IAS × (1 + 0.02 × altitude in thousands of feet) as a rough rule; use the navigation computer for the examination answer.

Wind triangle: heading = track ± wind correction angle; groundspeed = TAS × cos(WCA) + wind component along track. Compute WCA from sin(WCA) = (wind speed ÷ TAS) × sin(wind angle).

Time en route = distance ÷ groundspeed. Fuel used = time × hourly fuel flow; recalculate at each waypoint using actual groundspeed and remaining fuel.

PPL navigation log entries: waypoint, track, wind, heading, TAS, groundspeed, distance, ETA, fuel remaining. Every leg must show a positive fuel remaining at the destination alternate.

Pressure altitude and true altitude: true altitude = indicated altitude + 4 ft per 1000 ft per °C of ISA deviation (approximately), so cold air gives lower true altitude than indicated.

QNH and QFE: QNH gives altitude above mean sea level; QFE gives height above the aerodrome reference point. Setting the wrong subscale is a classic altimetry error; always cross-check the aerodrome elevation.

In-flight replanning: if actual groundspeed drops, recompute ETA and fuel at destination; if remaining fuel falls below final reserve plus alternate fuel, divert while a safe option exists.

Certificate of airworthiness, certificate of registration, and the aircraft radio station licence must be on board; the pilot licence and medical certificate must be carried or available as required by the state of registry.

The aircraft flight manual (AFM) and weight and balance schedule are the legal source for limitations; placards in the cockpit summarise the most critical limits.

Pre-flight documents include the flight plan or flight notification, weather briefing, NOTAMs, and the maintenance release confirming the aircraft is serviceable for the intended flight.

Aircraft maintenance: annual inspection, 100-hour inspection for commercial operations, and airworthiness directive compliance must be recorded before flight; an overdue AD grounds the aircraft.

Minimum fuel and emergency fuel declarations are distinct from a mayday; declare minimum fuel when committed to land with less than final reserve plus alternate, and emergency fuel when fuel exhaustion is imminent.

Weather minima for VFR: visibility and cloud clearance depend on airspace class; in Class G below 10,000 ft typical minima are 1 statute mile visibility and clear of cloud, but the national AIP prevails.

Runway incursion avoidance: read back all hold-short instructions, confirm the runway designator before entering, and use sterile cockpit procedures below 10,000 ft during critical phases.

Flight time and duty limits: logbook entries record flight time from engine start (or as defined by the authority) to engine shutdown; rest and duty limits are set by the operator or national regulation.