NCAA PPL Flight Performance & Planning flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Datum

A fixed reference plane or point from which all arms are measured for weight and balance. It is defined by the manufacturer and may lie forward of the nose.

Moment

The product of a weight and its arm from the datum, expressed in kilogram-metres or pound-inches. Summing moments and dividing by total weight gives the CG arm.

Maximum zero-fuel weight

The maximum weight of the aircraft with all payload and usable fuel excluded. It protects wing root bending and must not be exceeded even if total weight is below MTOW.

Forward CG effects

A forward centre of gravity increases the nose-down pitching moment, raising rotation forces, lengthening takeoff run and reducing cruise speed and range while improving stall recovery stability.

Aft CG effects

An aft centre of gravity reduces static stability and elevator effectiveness, can shorten takeoff run, increases cruise speed but risks deep stall and difficult recovery from spin.

Load shift formula

Distance a load must move equals (total weight × required CG shift) divided by the weight of the load being moved, keeping total weight constant.

Density altitude formula

Density altitude equals pressure altitude plus 120 times the difference between outside air temperature and ISA temperature at that pressure altitude, in degrees Celsius.

V1 decision speed

The speed at which a continued takeoff is assured after an engine failure. Below V1 the takeoff should be rejected; above V1 it must be continued.

V2 takeoff safety speed

The speed reached at 35 feet above the runway with one engine inoperative, providing the required climb gradient. It is the minimum speed for second-segment climb.

VREF landing speed

The landing reference speed, typically 1.3 times the stall speed in the landing configuration or the value stated in the aircraft flight manual.

Crosswind component

The component of wind perpendicular to the runway, calculated as wind speed multiplied by the sine of the angle between wind direction and runway heading.

Headwind component

The component of wind along the runway direction, calculated as wind speed multiplied by the cosine of the angle between wind direction and runway heading.

Stall speed and load factor

Stall speed increases with the square root of load factor. In a 60-degree bank level turn the load factor is 2, so stall speed rises by 41 percent.

Hydroplaning speed

The dynamic hydroplaning speed in knots is approximately nine times the square root of tyre pressure in psi. Above this speed on standing water, braking and steering degrade.

Runway slope effect

An upslope increases takeoff distance by roughly 5 to 10 percent per 1 percent of slope on light aircraft; a downslope shortens takeoff but lengthens landing distance.

Second segment climb

The climb segment from 35 feet to 400 feet with one engine inoperative. Transport twins require 2.4 percent gross gradient; net gradient is gross minus 0.8 percent.

Final reserve fuel

Fuel required to hold for 30 minutes at 1500 feet above the destination in a light aircraft, or as specified by the operator or authority, and never planned to be used.

Contingency fuel

Additional fuel, commonly 5 percent of trip fuel, carried to cover unforeseen deviations such as routing changes, weather avoidance or air traffic delays.

Wind correction angle

The angle between heading and track needed to counter drift, found from sine of the angle equal to wind speed divided by true airspeed times sine of the wind angle.

Groundspeed calculation

Groundspeed equals true airspeed multiplied by the cosine of the wind correction angle plus the along-track wind component. It determines time en route and fuel used.

True altitude correction

True altitude differs from indicated altitude by about 4 feet per 1000 feet per degree Celsius of ISA deviation, so cold air gives lower true altitude.

QNH versus QFE

QNH is the subscale setting giving altitude above mean sea level. QFE gives height above the aerodrome reference point and reads zero on the ground.

In-flight replanning

Recalculating estimated time of arrival and fuel remaining at each waypoint using actual groundspeed. If fuel falls below final reserve plus alternate, divert early.

Navigation log

A flight planning record listing waypoints, tracks, winds, headings, true airspeeds, groundspeeds, distances, estimated times of arrival and fuel remaining for each leg.

Certificate of airworthiness

The document confirming the aircraft meets its type design and is maintained in an airworthy condition. It must be on board and valid for the flight.

Certificate of registration

The document recording the state of registry, the owner and the aircraft nationality and registration marks. It must be carried on board.

Aircraft flight manual

The manufacturer's document containing limitations, operating procedures and performance data. It is the legal source for aircraft limitations and must be available.

Airworthiness directive

A mandatory instruction issued by the airworthiness authority to correct an unsafe condition. Compliance must be recorded, and an overdue directive grounds the aircraft.

Maintenance release

A certification that the aircraft has been inspected and is serviceable for the intended flight, issued by an appropriately licensed engineer or approved organisation.

Minimum fuel declaration

A statement to air traffic control that the aircraft is committed to landing with less than final reserve plus alternate fuel, and cannot accept significant further delay.

Emergency fuel declaration

A declaration made when fuel exhaustion is imminent and the aircraft requires priority handling. It is a distress condition and warrants a mayday call.

VFR cloud clearance

The minimum horizontal and vertical distance from cloud required for visual flight, which depends on airspace class and is specified in the national aeronautical information publication.

Sterile cockpit

A procedure restricting non-essential conversation and activity during critical phases such as taxi, takeoff, approach and landing, typically below 10,000 feet.